diff --git a/.ci/requirements-cibw.txt b/.ci/requirements-cibw.txt
index a1424ecc0..c4511439c 100644
--- a/.ci/requirements-cibw.txt
+++ b/.ci/requirements-cibw.txt
@@ -1 +1 @@
-cibuildwheel==2.21.2
+cibuildwheel==2.21.3
diff --git a/.github/workflows/wheels.yml b/.github/workflows/wheels.yml
index 2a4c86cd7..837e5ea91 100644
--- a/.github/workflows/wheels.yml
+++ b/.github/workflows/wheels.yml
@@ -41,7 +41,7 @@ env:
 
 jobs:
   build-1-QEMU-emulated-wheels:
-    if: github.event_name != 'schedule' && github.event_name != 'workflow_dispatch'
+    if: github.event_name != 'schedule'
     name: aarch64 ${{ matrix.python-version }} ${{ matrix.spec }}
     runs-on: ubuntu-latest
     strategy:
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 14d75c689..bdc335f32 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.6.3
+    rev: v0.6.9
     hooks:
       - id: ruff
         args: [--exit-non-zero-on-fix]
@@ -11,7 +11,7 @@ repos:
       - id: black
 
   - repo: https://github.com/PyCQA/bandit
-    rev: 1.7.9
+    rev: 1.7.10
     hooks:
     - id: bandit
       args: [--severity-level=high]
@@ -24,7 +24,7 @@ repos:
         exclude: (Makefile$|\.bat$|\.cmake$|\.eps$|\.fits$|\.gd$|\.opt$)
 
   - repo: https://github.com/pre-commit/mirrors-clang-format
-    rev: v18.1.8
+    rev: v19.1.1
     hooks:
       - id: clang-format
         types: [c]
@@ -36,7 +36,7 @@ repos:
       - id: rst-backticks
 
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v4.6.0
+    rev: v5.0.0
     hooks:
       - id: check-executables-have-shebangs
       - id: check-shebang-scripts-are-executable
@@ -50,29 +50,29 @@ repos:
         exclude: ^.github/.*TEMPLATE|^Tests/(fonts|images)/
 
   - repo: https://github.com/python-jsonschema/check-jsonschema
-    rev: 0.29.2
+    rev: 0.29.3
     hooks:
       - id: check-github-workflows
       - id: check-readthedocs
       - id: check-renovate
 
   - repo: https://github.com/sphinx-contrib/sphinx-lint
-    rev: v0.9.1
+    rev: v1.0.0
     hooks:
       - id: sphinx-lint
 
   - repo: https://github.com/tox-dev/pyproject-fmt
-    rev: 2.2.1
+    rev: 2.2.4
     hooks:
       - id: pyproject-fmt
 
   - repo: https://github.com/abravalheri/validate-pyproject
-    rev: v0.19
+    rev: v0.20.2
     hooks:
       - id: validate-pyproject
 
   - repo: https://github.com/tox-dev/tox-ini-fmt
-    rev: 1.3.1
+    rev: 1.4.1
     hooks:
       - id: tox-ini-fmt
 
diff --git a/CHANGES.rst b/CHANGES.rst
index cc891ed1d..c965d60a6 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -5,6 +5,15 @@ Changelog (Pillow)
 11.0.0 (unreleased)
 -------------------
 
+- Do not close provided file handles with libtiff when saving #8458
+  [radarhere]
+
+- Support ImageFilter.BuiltinFilter for I;16* images #8438
+  [radarhere]
+
+- Use ImagingCore.ptr instead of ImagingCore.id #8341
+  [homm, radarhere, hugovk]
+
 - Updated EPS mode when opening images without transparency #8281
   [Yay295, radarhere]
 
diff --git a/Makefile b/Makefile
index ec4159627..53164b08a 100644
--- a/Makefile
+++ b/Makefile
@@ -17,12 +17,10 @@ coverage:
 .PHONY: doc
 .PHONY: html
 doc html:
-	python3 -c "import PIL" > /dev/null 2>&1 || python3 -m pip install .
 	$(MAKE) -C docs html
 
 .PHONY: htmlview
 htmlview:
-	python3 -c "import PIL" > /dev/null 2>&1 || python3 -m pip install .
 	$(MAKE) -C docs htmlview
 
 .PHONY: doccheck
diff --git a/Tests/test_features.py b/Tests/test_features.py
index 807782847..ed7929973 100644
--- a/Tests/test_features.py
+++ b/Tests/test_features.py
@@ -56,17 +56,17 @@ def test_version() -> None:
 
 def test_webp_transparency() -> None:
     with pytest.warns(DeprecationWarning):
-        assert features.check("transp_webp") == features.check_module("webp")
+        assert (features.check("transp_webp") or False) == features.check_module("webp")
 
 
 def test_webp_mux() -> None:
     with pytest.warns(DeprecationWarning):
-        assert features.check("webp_mux") == features.check_module("webp")
+        assert (features.check("webp_mux") or False) == features.check_module("webp")
 
 
 def test_webp_anim() -> None:
     with pytest.warns(DeprecationWarning):
-        assert features.check("webp_anim") == features.check_module("webp")
+        assert (features.check("webp_anim") or False) == features.check_module("webp")
 
 
 @skip_unless_feature("libjpeg_turbo")
diff --git a/Tests/test_file_tiff.py b/Tests/test_file_tiff.py
index 47632b8fa..509e48879 100644
--- a/Tests/test_file_tiff.py
+++ b/Tests/test_file_tiff.py
@@ -116,10 +116,6 @@ class TestFileTiff:
         with Image.open("Tests/images/hopper_bigtiff.tif") as im:
             assert isinstance(im, TiffImagePlugin.TiffImageFile)
 
-            # The data type of this file's StripOffsets tag is LONG8,
-            # which is not yet supported for offset data when saving multiple frames.
-            del im.tag_v2[273]
-
             outfile = str(tmp_path / "temp.tif")
             im.save(outfile, save_all=True, append_images=[im], tiffinfo=im.tag_v2)
 
@@ -767,6 +763,20 @@ class TestFileTiff:
             assert isinstance(reread, TiffImagePlugin.TiffImageFile)
             assert reread.n_frames == 3
 
+    def test_fixoffsets(self) -> None:
+        b = BytesIO(b"II\x2a\x00\x00\x00\x00\x00")
+        with TiffImagePlugin.AppendingTiffWriter(b) as a:
+            b.seek(0)
+            a.fixOffsets(1, isShort=True)
+
+            b.seek(0)
+            a.fixOffsets(1, isLong=True)
+
+            # Neither short nor long
+            b.seek(0)
+            with pytest.raises(RuntimeError):
+                a.fixOffsets(1)
+
     def test_saving_icc_profile(self, tmp_path: Path) -> None:
         # Tests saving TIFF with icc_profile set.
         # At the time of writing this will only work for non-compressed tiffs
diff --git a/Tests/test_image_filter.py b/Tests/test_image_filter.py
index 412ab44c3..e566cd055 100644
--- a/Tests/test_image_filter.py
+++ b/Tests/test_image_filter.py
@@ -35,16 +35,25 @@ from .helper import assert_image_equal, hopper
         ImageFilter.UnsharpMask(10),
     ),
 )
-@pytest.mark.parametrize("mode", ("L", "I", "RGB", "CMYK"))
-def test_sanity(filter_to_apply: ImageFilter.Filter, mode: str) -> None:
+@pytest.mark.parametrize(
+    "mode", ("L", "I", "I;16", "I;16L", "I;16B", "I;16N", "RGB", "CMYK")
+)
+def test_sanity(
+    filter_to_apply: ImageFilter.Filter | type[ImageFilter.Filter], mode: str
+) -> None:
     im = hopper(mode)
-    if mode != "I" or isinstance(filter_to_apply, ImageFilter.BuiltinFilter):
+    if mode[0] != "I" or (
+        callable(filter_to_apply)
+        and issubclass(filter_to_apply, ImageFilter.BuiltinFilter)
+    ):
         out = im.filter(filter_to_apply)
         assert out.mode == im.mode
         assert out.size == im.size
 
 
-@pytest.mark.parametrize("mode", ("L", "I", "RGB", "CMYK"))
+@pytest.mark.parametrize(
+    "mode", ("L", "I", "I;16", "I;16L", "I;16B", "I;16N", "RGB", "CMYK")
+)
 def test_sanity_error(mode: str) -> None:
     im = hopper(mode)
     with pytest.raises(TypeError):
@@ -145,7 +154,9 @@ def test_kernel_not_enough_coefficients() -> None:
         ImageFilter.Kernel((3, 3), (0, 0))
 
 
-@pytest.mark.parametrize("mode", ("L", "LA", "I", "RGB", "CMYK"))
+@pytest.mark.parametrize(
+    "mode", ("L", "LA", "I", "I;16", "I;16L", "I;16B", "I;16N", "RGB", "CMYK")
+)
 def test_consistency_3x3(mode: str) -> None:
     with Image.open("Tests/images/hopper.bmp") as source:
         with Image.open("Tests/images/hopper_emboss.bmp") as reference:
@@ -161,7 +172,9 @@ def test_consistency_3x3(mode: str) -> None:
             assert_image_equal(source.filter(kernel), reference)
 
 
-@pytest.mark.parametrize("mode", ("L", "LA", "I", "RGB", "CMYK"))
+@pytest.mark.parametrize(
+    "mode", ("L", "LA", "I", "I;16", "I;16L", "I;16B", "I;16N", "RGB", "CMYK")
+)
 def test_consistency_5x5(mode: str) -> None:
     with Image.open("Tests/images/hopper.bmp") as source:
         with Image.open("Tests/images/hopper_emboss_more.bmp") as reference:
diff --git a/Tests/test_image_getim.py b/Tests/test_image_getim.py
index 9afa02b0a..fa58492fc 100644
--- a/Tests/test_image_getim.py
+++ b/Tests/test_image_getim.py
@@ -1,11 +1,19 @@
 from __future__ import annotations
 
+import pytest
+
 from .helper import hopper
 
 
 def test_sanity() -> None:
     im = hopper()
-    type_repr = repr(type(im.getim()))
 
+    type_repr = repr(type(im.getim()))
     assert "PyCapsule" in type_repr
-    assert isinstance(im.im.id, int)
+
+    with pytest.warns(DeprecationWarning):
+        assert isinstance(im.im.id, int)
+
+    with pytest.warns(DeprecationWarning):
+        ptrs = dict(im.im.unsafe_ptrs)
+    assert ptrs.keys() == {"image8", "image32", "image"}
diff --git a/Tests/test_imagemorph.py b/Tests/test_imagemorph.py
index 80d8c3815..6180a7b5d 100644
--- a/Tests/test_imagemorph.py
+++ b/Tests/test_imagemorph.py
@@ -324,17 +324,17 @@ def test_set_lut() -> None:
 
 def test_wrong_mode() -> None:
     lut = ImageMorph.LutBuilder(op_name="corner").build_lut()
-    imrgb = Image.new("RGB", (10, 10))
-    iml = Image.new("L", (10, 10))
+    imrgb_ptr = Image.new("RGB", (10, 10)).getim()
+    iml_ptr = Image.new("L", (10, 10)).getim()
 
     with pytest.raises(RuntimeError):
-        _imagingmorph.apply(bytes(lut), imrgb.im.id, iml.im.id)
+        _imagingmorph.apply(bytes(lut), imrgb_ptr, iml_ptr)
 
     with pytest.raises(RuntimeError):
-        _imagingmorph.apply(bytes(lut), iml.im.id, imrgb.im.id)
+        _imagingmorph.apply(bytes(lut), iml_ptr, imrgb_ptr)
 
     with pytest.raises(RuntimeError):
-        _imagingmorph.match(bytes(lut), imrgb.im.id)
+        _imagingmorph.match(bytes(lut), imrgb_ptr)
 
     # Should not raise
-    _imagingmorph.match(bytes(lut), iml.im.id)
+    _imagingmorph.match(bytes(lut), iml_ptr)
diff --git a/Tests/test_imageshow.py b/Tests/test_imageshow.py
index 67c32783f..7a2f58767 100644
--- a/Tests/test_imageshow.py
+++ b/Tests/test_imageshow.py
@@ -117,5 +117,5 @@ def test_ipythonviewer() -> None:
     else:
         pytest.fail("IPythonViewer not found")
 
-    im = hopper()
-    assert test_viewer.show(im) == 1
+    with hopper() as im:
+        assert test_viewer.show(im) == 1
diff --git a/docs/Makefile b/docs/Makefile
index 8f13f1aea..e90af0519 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -46,7 +46,7 @@ clean:
 	-rm -rf $(BUILDDIR)/*
 
 install-sphinx:
-	$(PYTHON) -m pip install --quiet furo olefile sphinx sphinx-copybutton sphinx-inline-tabs sphinxext-opengraph
+	$(PYTHON) -m pip install -e ..[docs]
 
 .PHONY: html
 html:
diff --git a/docs/conf.py b/docs/conf.py
index a0f5867d7..b81d86c6c 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -22,7 +22,7 @@ import PIL
 # -- General configuration ------------------------------------------------
 
 # If your documentation needs a minimal Sphinx version, state it here.
-needs_sphinx = "7.3"
+needs_sphinx = "8.1"
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
@@ -121,7 +121,7 @@ nitpicky = True
 # generating warnings in “nitpicky mode”. Note that type should include the domain name
 # if present. Example entries would be ('py:func', 'int') or
 # ('envvar', 'LD_LIBRARY_PATH').
-nitpick_ignore = [("py:class", "_io.BytesIO")]
+nitpick_ignore = [("py:class", "_io.BytesIO"), ("py:class", "_CmsProfileCompatible")]
 
 
 # -- Options for HTML output ----------------------------------------------
@@ -338,8 +338,6 @@ linkcheck_allowed_redirects = {
 # https://www.sphinx-doc.org/en/master/usage/extensions/extlinks.html
 _repo = "https://github.com/python-pillow/Pillow/"
 extlinks = {
-    "cve": ("https://www.cve.org/CVERecord?id=CVE-%s", "CVE-%s"),
-    "cwe": ("https://cwe.mitre.org/data/definitions/%s.html", "CWE-%s"),
     "issue": (_repo + "issues/%s", "#%s"),
     "pr": (_repo + "pull/%s", "#%s"),
     "pypi": ("https://pypi.org/project/%s/", "%s"),
diff --git a/docs/deprecations.rst b/docs/deprecations.rst
index 366360dbe..25607e27c 100644
--- a/docs/deprecations.rst
+++ b/docs/deprecations.rst
@@ -165,6 +165,16 @@ Specific WebP Feature Checks
 ``True`` if the WebP module is installed, until they are removed in Pillow
 12.0.0 (2025-10-15).
 
+Get internal pointers to objects
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. deprecated:: 11.0.0
+
+``Image.core.ImagingCore.id`` and ``Image.core.ImagingCore.unsafe_ptrs`` have been
+deprecated and will be removed in Pillow 12 (2025-10-15). They were used for obtaining
+raw pointers to ``ImagingCore`` internals. To interact with C code, you can use
+``Image.Image.getim()``, which returns a ``Capsule`` object.
+
 Removed features
 ----------------
 
diff --git a/docs/releasenotes/11.0.0.rst b/docs/releasenotes/11.0.0.rst
index 1218c5014..d5f5934f4 100644
--- a/docs/releasenotes/11.0.0.rst
+++ b/docs/releasenotes/11.0.0.rst
@@ -73,6 +73,16 @@ vulnerability introduced in FreeType 2.6 (:cve:`2020-15999`).
 
 .. _2.10.4: https://sourceforge.net/projects/freetype/files/freetype2/2.10.4/
 
+Get internal pointers to objects
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. deprecated:: 11.0.0
+
+``Image.core.ImagingCore.id`` and ``Image.core.ImagingCore.unsafe_ptrs`` have been
+deprecated and will be removed in Pillow 12 (2025-10-15). They were used for obtaining
+raw pointers to ``ImagingCore`` internals. To interact with C code, you can use
+``Image.Image.getim()``, which returns a ``Capsule`` object.
+
 ICNS (width, height, scale) sizes
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
diff --git a/pyproject.toml b/pyproject.toml
index 0d0a6f170..132030c99 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -43,7 +43,7 @@ dynamic = [
 optional-dependencies.docs = [
   "furo",
   "olefile",
-  "sphinx>=7.3",
+  "sphinx>=8.1",
   "sphinx-copybutton",
   "sphinx-inline-tabs",
   "sphinxext-opengraph",
diff --git a/src/PIL/Image.py b/src/PIL/Image.py
index d056a5052..73b84b344 100644
--- a/src/PIL/Image.py
+++ b/src/PIL/Image.py
@@ -225,12 +225,7 @@ if TYPE_CHECKING:
     from IPython.lib.pretty import PrettyPrinter
 
     from . import ImageFile, ImageFilter, ImagePalette, ImageQt, TiffImagePlugin
-    from ._typing import NumpyArray, StrOrBytesPath, TypeGuard
-
-    if sys.version_info >= (3, 13):
-        from types import CapsuleType
-    else:
-        CapsuleType = object
+    from ._typing import CapsuleType, NumpyArray, StrOrBytesPath, TypeGuard
 ID: list[str] = []
 OPEN: dict[
     str,
diff --git a/src/PIL/ImageCms.py b/src/PIL/ImageCms.py
index ec10230f1..fdfbee789 100644
--- a/src/PIL/ImageCms.py
+++ b/src/PIL/ImageCms.py
@@ -31,6 +31,10 @@ from ._typing import SupportsRead
 
 try:
     from . import _imagingcms as core
+
+    _CmsProfileCompatible = Union[
+        str, SupportsRead[bytes], core.CmsProfile, "ImageCmsProfile"
+    ]
 except ImportError as ex:
     # Allow error import for doc purposes, but error out when accessing
     # anything in core.
@@ -349,19 +353,17 @@ class ImageCmsTransform(Image.ImagePointHandler):
         return self.apply(im)
 
     def apply(self, im: Image.Image, imOut: Image.Image | None = None) -> Image.Image:
-        im.load()
         if imOut is None:
             imOut = Image.new(self.output_mode, im.size, None)
-        self.transform.apply(im.im.id, imOut.im.id)
+        self.transform.apply(im.getim(), imOut.getim())
         imOut.info["icc_profile"] = self.output_profile.tobytes()
         return imOut
 
     def apply_in_place(self, im: Image.Image) -> Image.Image:
-        im.load()
         if im.mode != self.output_mode:
             msg = "mode mismatch"
             raise ValueError(msg)  # wrong output mode
-        self.transform.apply(im.im.id, im.im.id)
+        self.transform.apply(im.getim(), im.getim())
         im.info["icc_profile"] = self.output_profile.tobytes()
         return im
 
@@ -391,10 +393,6 @@ def get_display_profile(handle: SupportsInt | None = None) -> ImageCmsProfile |
 # pyCMS compatible layer
 # --------------------------------------------------------------------.
 
-_CmsProfileCompatible = Union[
-    str, SupportsRead[bytes], core.CmsProfile, ImageCmsProfile
-]
-
 
 class PyCMSError(Exception):
     """(pyCMS) Exception class.
diff --git a/src/PIL/ImageMath.py b/src/PIL/ImageMath.py
index 191ca8524..15464947d 100644
--- a/src/PIL/ImageMath.py
+++ b/src/PIL/ImageMath.py
@@ -59,13 +59,12 @@ class _Operand:
         if im2 is None:
             # unary operation
             out = Image.new(mode or im_1.mode, im_1.size, None)
-            im_1.load()
             try:
                 op = getattr(_imagingmath, f"{op}_{im_1.mode}")
             except AttributeError as e:
                 msg = f"bad operand type for '{op}'"
                 raise TypeError(msg) from e
-            _imagingmath.unop(op, out.im.id, im_1.im.id)
+            _imagingmath.unop(op, out.getim(), im_1.getim())
         else:
             # binary operation
             im_2 = self.__fixup(im2)
@@ -86,14 +85,12 @@ class _Operand:
                 if im_2.size != size:
                     im_2 = im_2.crop((0, 0) + size)
             out = Image.new(mode or im_1.mode, im_1.size, None)
-            im_1.load()
-            im_2.load()
             try:
                 op = getattr(_imagingmath, f"{op}_{im_1.mode}")
             except AttributeError as e:
                 msg = f"bad operand type for '{op}'"
                 raise TypeError(msg) from e
-            _imagingmath.binop(op, out.im.id, im_1.im.id, im_2.im.id)
+            _imagingmath.binop(op, out.getim(), im_1.getim(), im_2.getim())
         return _Operand(out)
 
     # unary operators
diff --git a/src/PIL/ImageMorph.py b/src/PIL/ImageMorph.py
index 6a43983d3..f0a066b5b 100644
--- a/src/PIL/ImageMorph.py
+++ b/src/PIL/ImageMorph.py
@@ -213,7 +213,7 @@ class MorphOp:
             msg = "Image mode must be L"
             raise ValueError(msg)
         outimage = Image.new(image.mode, image.size, None)
-        count = _imagingmorph.apply(bytes(self.lut), image.im.id, outimage.im.id)
+        count = _imagingmorph.apply(bytes(self.lut), image.getim(), outimage.getim())
         return count, outimage
 
     def match(self, image: Image.Image) -> list[tuple[int, int]]:
@@ -229,7 +229,7 @@ class MorphOp:
         if image.mode != "L":
             msg = "Image mode must be L"
             raise ValueError(msg)
-        return _imagingmorph.match(bytes(self.lut), image.im.id)
+        return _imagingmorph.match(bytes(self.lut), image.getim())
 
     def get_on_pixels(self, image: Image.Image) -> list[tuple[int, int]]:
         """Get a list of all turned on pixels in a binary image
@@ -240,7 +240,7 @@ class MorphOp:
         if image.mode != "L":
             msg = "Image mode must be L"
             raise ValueError(msg)
-        return _imagingmorph.get_on_pixels(image.im.id)
+        return _imagingmorph.get_on_pixels(image.getim())
 
     def load_lut(self, filename: str) -> None:
         """Load an operator from an mrl file"""
diff --git a/src/PIL/ImageTk.py b/src/PIL/ImageTk.py
index a788c9d1f..bf29fdba5 100644
--- a/src/PIL/ImageTk.py
+++ b/src/PIL/ImageTk.py
@@ -32,23 +32,12 @@ from typing import TYPE_CHECKING, Any, cast
 
 from . import Image, ImageFile
 
+if TYPE_CHECKING:
+    from ._typing import CapsuleType
+
 # --------------------------------------------------------------------
 # Check for Tkinter interface hooks
 
-_pilbitmap_ok = None
-
-
-def _pilbitmap_check() -> int:
-    global _pilbitmap_ok
-    if _pilbitmap_ok is None:
-        try:
-            im = Image.new("1", (1, 1))
-            tkinter.BitmapImage(data=f"PIL:{im.im.id}")
-            _pilbitmap_ok = 1
-        except tkinter.TclError:
-            _pilbitmap_ok = 0
-    return _pilbitmap_ok
-
 
 def _get_image_from_kw(kw: dict[str, Any]) -> ImageFile.ImageFile | None:
     source = None
@@ -62,18 +51,18 @@ def _get_image_from_kw(kw: dict[str, Any]) -> ImageFile.ImageFile | None:
 
 
 def _pyimagingtkcall(
-    command: str, photo: PhotoImage | tkinter.PhotoImage, id: int
+    command: str, photo: PhotoImage | tkinter.PhotoImage, ptr: CapsuleType
 ) -> None:
     tk = photo.tk
     try:
-        tk.call(command, photo, id)
+        tk.call(command, photo, repr(ptr))
     except tkinter.TclError:
         # activate Tkinter hook
         # may raise an error if it cannot attach to Tkinter
         from . import _imagingtk
 
         _imagingtk.tkinit(tk.interpaddr())
-        tk.call(command, photo, id)
+        tk.call(command, photo, repr(ptr))
 
 
 # --------------------------------------------------------------------
@@ -142,7 +131,10 @@ class PhotoImage:
             self.paste(image)
 
     def __del__(self) -> None:
-        name = self.__photo.name
+        try:
+            name = self.__photo.name
+        except AttributeError:
+            return
         self.__photo.name = None
         try:
             self.__photo.tk.call("image", "delete", name)
@@ -185,15 +177,14 @@ class PhotoImage:
                    the bitmap image.
         """
         # convert to blittable
-        im.load()
+        ptr = im.getim()
         image = im.im
-        if image.isblock() and im.mode == self.__mode:
-            block = image
-        else:
-            block = image.new_block(self.__mode, im.size)
+        if not image.isblock() or im.mode != self.__mode:
+            block = Image.core.new_block(self.__mode, im.size)
             image.convert2(block, image)  # convert directly between buffers
+            ptr = block.ptr
 
-        _pyimagingtkcall("PyImagingPhoto", self.__photo, block.id)
+        _pyimagingtkcall("PyImagingPhoto", self.__photo, ptr)
 
 
 # --------------------------------------------------------------------
@@ -225,18 +216,13 @@ class BitmapImage:
         self.__mode = image.mode
         self.__size = image.size
 
-        if _pilbitmap_check():
-            # fast way (requires the pilbitmap booster patch)
-            image.load()
-            kw["data"] = f"PIL:{image.im.id}"
-            self.__im = image  # must keep a reference
-        else:
-            # slow but safe way
-            kw["data"] = image.tobitmap()
-        self.__photo = tkinter.BitmapImage(**kw)
+        self.__photo = tkinter.BitmapImage(data=image.tobitmap(), **kw)
 
     def __del__(self) -> None:
-        name = self.__photo.name
+        try:
+            name = self.__photo.name
+        except AttributeError:
+            return
         self.__photo.name = None
         try:
             self.__photo.tk.call("image", "delete", name)
@@ -273,9 +259,8 @@ class BitmapImage:
 def getimage(photo: PhotoImage) -> Image.Image:
     """Copies the contents of a PhotoImage to a PIL image memory."""
     im = Image.new("RGBA", (photo.width(), photo.height()))
-    block = im.im
 
-    _pyimagingtkcall("PyImagingPhotoGet", photo, block.id)
+    _pyimagingtkcall("PyImagingPhotoGet", photo, im.getim())
 
     return im
 
diff --git a/src/PIL/TiffImagePlugin.py b/src/PIL/TiffImagePlugin.py
index 0b7dc68eb..5c50e2efd 100644
--- a/src/PIL/TiffImagePlugin.py
+++ b/src/PIL/TiffImagePlugin.py
@@ -1869,7 +1869,7 @@ def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
         if hasattr(fp, "fileno"):
             try:
                 fp.seek(0)
-                _fp = os.dup(fp.fileno())
+                _fp = fp.fileno()
             except io.UnsupportedOperation:
                 pass
 
@@ -1942,17 +1942,11 @@ def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
         encoder = Image._getencoder(im.mode, "libtiff", a, encoderconfig)
         encoder.setimage(im.im, (0, 0) + im.size)
         while True:
-            # undone, change to self.decodermaxblock:
-            errcode, data = encoder.encode(16 * 1024)[1:]
+            errcode, data = encoder.encode(ImageFile.MAXBLOCK)[1:]
             if not _fp:
                 fp.write(data)
             if errcode:
                 break
-        if _fp:
-            try:
-                os.close(_fp)
-            except OSError:
-                pass
         if errcode < 0:
             msg = f"encoder error {errcode} when writing image file"
             raise OSError(msg)
@@ -2126,13 +2120,24 @@ class AppendingTiffWriter(io.BytesIO):
     def write(self, data: Buffer, /) -> int:
         return self.f.write(data)
 
-    def readShort(self) -> int:
-        (value,) = struct.unpack(self.shortFmt, self.f.read(2))
+    def _fmt(self, field_size: int) -> str:
+        try:
+            return {2: "H", 4: "L", 8: "Q"}[field_size]
+        except KeyError:
+            msg = "offset is not supported"
+            raise RuntimeError(msg)
+
+    def _read(self, field_size: int) -> int:
+        (value,) = struct.unpack(
+            self.endian + self._fmt(field_size), self.f.read(field_size)
+        )
         return value
 
+    def readShort(self) -> int:
+        return self._read(2)
+
     def readLong(self) -> int:
-        (value,) = struct.unpack(self.longFmt, self.f.read(4))
-        return value
+        return self._read(4)
 
     @staticmethod
     def _verify_bytes_written(bytes_written: int | None, expected: int) -> None:
@@ -2145,15 +2150,18 @@ class AppendingTiffWriter(io.BytesIO):
         bytes_written = self.f.write(struct.pack(self.longFmt, value))
         self._verify_bytes_written(bytes_written, 4)
 
+    def _rewriteLast(self, value: int, field_size: int) -> None:
+        self.f.seek(-field_size, os.SEEK_CUR)
+        bytes_written = self.f.write(
+            struct.pack(self.endian + self._fmt(field_size), value)
+        )
+        self._verify_bytes_written(bytes_written, field_size)
+
     def rewriteLastShort(self, value: int) -> None:
-        self.f.seek(-2, os.SEEK_CUR)
-        bytes_written = self.f.write(struct.pack(self.shortFmt, value))
-        self._verify_bytes_written(bytes_written, 2)
+        return self._rewriteLast(value, 2)
 
     def rewriteLastLong(self, value: int) -> None:
-        self.f.seek(-4, os.SEEK_CUR)
-        bytes_written = self.f.write(struct.pack(self.longFmt, value))
-        self._verify_bytes_written(bytes_written, 4)
+        return self._rewriteLast(value, 4)
 
     def writeShort(self, value: int) -> None:
         bytes_written = self.f.write(struct.pack(self.shortFmt, value))
@@ -2185,32 +2193,22 @@ class AppendingTiffWriter(io.BytesIO):
                 cur_pos = self.f.tell()
 
                 if is_local:
-                    self.fixOffsets(
-                        count, isShort=(field_size == 2), isLong=(field_size == 4)
-                    )
+                    self._fixOffsets(count, field_size)
                     self.f.seek(cur_pos + 4)
                 else:
                     self.f.seek(offset)
-                    self.fixOffsets(
-                        count, isShort=(field_size == 2), isLong=(field_size == 4)
-                    )
+                    self._fixOffsets(count, field_size)
                     self.f.seek(cur_pos)
 
             elif is_local:
                 # skip the locally stored value that is not an offset
                 self.f.seek(4, os.SEEK_CUR)
 
-    def fixOffsets(
-        self, count: int, isShort: bool = False, isLong: bool = False
-    ) -> None:
-        if not isShort and not isLong:
-            msg = "offset is neither short nor long"
-            raise RuntimeError(msg)
-
+    def _fixOffsets(self, count: int, field_size: int) -> None:
         for i in range(count):
-            offset = self.readShort() if isShort else self.readLong()
+            offset = self._read(field_size)
             offset += self.offsetOfNewPage
-            if isShort and offset >= 65536:
+            if field_size == 2 and offset >= 65536:
                 # offset is now too large - we must convert shorts to longs
                 if count != 1:
                     msg = "not implemented"
@@ -2222,10 +2220,19 @@ class AppendingTiffWriter(io.BytesIO):
                 self.f.seek(-10, os.SEEK_CUR)
                 self.writeShort(TiffTags.LONG)  # rewrite the type to LONG
                 self.f.seek(8, os.SEEK_CUR)
-            elif isShort:
-                self.rewriteLastShort(offset)
             else:
-                self.rewriteLastLong(offset)
+                self._rewriteLast(offset, field_size)
+
+    def fixOffsets(
+        self, count: int, isShort: bool = False, isLong: bool = False
+    ) -> None:
+        if isShort:
+            field_size = 2
+        elif isLong:
+            field_size = 4
+        else:
+            field_size = 0
+        return self._fixOffsets(count, field_size)
 
 
 def _save_all(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
diff --git a/src/PIL/_imagingcms.pyi b/src/PIL/_imagingcms.pyi
index 2abd6d0f7..ddcf93ab1 100644
--- a/src/PIL/_imagingcms.pyi
+++ b/src/PIL/_imagingcms.pyi
@@ -2,6 +2,8 @@ import datetime
 import sys
 from typing import Literal, SupportsFloat, TypedDict
 
+from ._typing import CapsuleType
+
 littlecms_version: str | None
 
 _Tuple3f = tuple[float, float, float]
@@ -108,7 +110,7 @@ class CmsProfile:
     def is_intent_supported(self, intent: int, direction: int, /) -> int: ...
 
 class CmsTransform:
-    def apply(self, id_in: int, id_out: int) -> int: ...
+    def apply(self, id_in: CapsuleType, id_out: CapsuleType) -> int: ...
 
 def profile_open(profile: str, /) -> CmsProfile: ...
 def profile_frombytes(profile: bytes, /) -> CmsProfile: ...
diff --git a/src/PIL/_typing.py b/src/PIL/_typing.py
index da49f7c5d..0a7d87cc2 100644
--- a/src/PIL/_typing.py
+++ b/src/PIL/_typing.py
@@ -15,6 +15,11 @@ if TYPE_CHECKING:
     except (ImportError, AttributeError):
         pass
 
+if sys.version_info >= (3, 13):
+    from types import CapsuleType
+else:
+    CapsuleType = object
+
 if sys.version_info >= (3, 12):
     from collections.abc import Buffer
 else:
diff --git a/src/PIL/features.py b/src/PIL/features.py
index 24c5ee978..75d59e01c 100644
--- a/src/PIL/features.py
+++ b/src/PIL/features.py
@@ -146,10 +146,11 @@ def check_feature(feature: str) -> bool | None:
 
     module, flag, ver = features[feature]
 
+    if isinstance(flag, bool):
+        deprecate(f'check_feature("{feature}")', 12)
     try:
         imported_module = __import__(module, fromlist=["PIL"])
         if isinstance(flag, bool):
-            deprecate(f'check_feature("{feature}")', 12)
             return flag
         return getattr(imported_module, flag)
     except ModuleNotFoundError:
diff --git a/src/Tk/tkImaging.c b/src/Tk/tkImaging.c
index 727ee6bed..a36c3e0bd 100644
--- a/src/Tk/tkImaging.c
+++ b/src/Tk/tkImaging.c
@@ -56,19 +56,34 @@ static Tk_PhotoPutBlock_t TK_PHOTO_PUT_BLOCK;
 
 static Imaging
 ImagingFind(const char *name) {
-    Py_ssize_t id;
+    PyObject *capsule;
+    int direct_pointer = 0;
+    const char *expected = "capsule object \"" IMAGING_MAGIC "\" at 0x";
 
-    /* FIXME: use CObject instead? */
-#if defined(_WIN64)
-    id = _atoi64(name);
-#else
-    id = atol(name);
-#endif
-    if (!id) {
+    if (name[0] == '<') {
+        name++;
+    } else {
+        // Special case for PyPy, where the string representation of a Capsule
+        // refers directly to the pointer itself, not to the PyCapsule object.
+        direct_pointer = 1;
+    }
+
+    if (strncmp(name, expected, strlen(expected))) {
         return NULL;
     }
 
-    return (Imaging)id;
+    capsule = (PyObject *)strtoull(name + strlen(expected), NULL, 16);
+
+    if (direct_pointer) {
+        return (Imaging)capsule;
+    }
+
+    if (!PyCapsule_IsValid(capsule, IMAGING_MAGIC)) {
+        PyErr_Format(PyExc_TypeError, "Expected '%s' Capsule", IMAGING_MAGIC);
+        return NULL;
+    }
+
+    return (Imaging)PyCapsule_GetPointer(capsule, IMAGING_MAGIC);
 }
 
 static int
diff --git a/src/_imaging.c b/src/_imaging.c
index 426036335..2db4486b2 100644
--- a/src/_imaging.c
+++ b/src/_imaging.c
@@ -3670,15 +3670,12 @@ static struct PyMethodDef methods[] = {
     /* Unsharpmask extension */
     {"gaussian_blur", (PyCFunction)_gaussian_blur, METH_VARARGS},
     {"unsharp_mask", (PyCFunction)_unsharp_mask, METH_VARARGS},
-
     {"box_blur", (PyCFunction)_box_blur, METH_VARARGS},
 
     /* Special effects */
     {"effect_spread", (PyCFunction)_effect_spread, METH_VARARGS},
 
     /* Misc. */
-    {"new_block", (PyCFunction)_new_block, METH_VARARGS},
-
     {"save_ppm", (PyCFunction)_save_ppm, METH_VARARGS},
 
     {NULL, NULL} /* sentinel */
@@ -3703,16 +3700,40 @@ _getattr_bands(ImagingObject *self, void *closure) {
 
 static PyObject *
 _getattr_id(ImagingObject *self, void *closure) {
+    if (PyErr_WarnEx(
+            PyExc_DeprecationWarning,
+            "id property is deprecated and will be removed in Pillow 12 (2025-10-15)",
+            1
+        ) < 0) {
+        return NULL;
+    }
     return PyLong_FromSsize_t((Py_ssize_t)self->image);
 }
 
+static void
+_ptr_destructor(PyObject *capsule) {
+    PyObject *self = (PyObject *)PyCapsule_GetContext(capsule);
+    Py_DECREF(self);
+}
+
 static PyObject *
 _getattr_ptr(ImagingObject *self, void *closure) {
-    return PyCapsule_New(self->image, IMAGING_MAGIC, NULL);
+    PyObject *capsule = PyCapsule_New(self->image, IMAGING_MAGIC, _ptr_destructor);
+    Py_INCREF(self);
+    PyCapsule_SetContext(capsule, self);
+    return capsule;
 }
 
 static PyObject *
 _getattr_unsafe_ptrs(ImagingObject *self, void *closure) {
+    if (PyErr_WarnEx(
+            PyExc_DeprecationWarning,
+            "unsafe_ptrs property is deprecated and will be removed in Pillow 12 "
+            "(2025-10-15)",
+            1
+        ) < 0) {
+        return NULL;
+    }
     return Py_BuildValue(
         "(sn)(sn)(sn)",
         "image8",
@@ -4194,6 +4215,7 @@ static PyMethodDef functions[] = {
     {"blend", (PyCFunction)_blend, METH_VARARGS},
     {"fill", (PyCFunction)_fill, METH_VARARGS},
     {"new", (PyCFunction)_new, METH_VARARGS},
+    {"new_block", (PyCFunction)_new_block, METH_VARARGS},
     {"merge", (PyCFunction)_merge, METH_VARARGS},
 
     /* Functions */
diff --git a/src/_imagingcms.c b/src/_imagingcms.c
index bafe787a7..1823bcf03 100644
--- a/src/_imagingcms.c
+++ b/src/_imagingcms.c
@@ -531,23 +531,24 @@ buildProofTransform(PyObject *self, PyObject *args) {
 
 static PyObject *
 cms_transform_apply(CmsTransformObject *self, PyObject *args) {
-    Py_ssize_t idIn;
-    Py_ssize_t idOut;
+    PyObject *i0, *i1;
     Imaging im;
     Imaging imOut;
 
-    int result;
-
-    if (!PyArg_ParseTuple(args, "nn:apply", &idIn, &idOut)) {
+    if (!PyArg_ParseTuple(args, "OO:apply", &i0, &i1)) {
         return NULL;
     }
 
-    im = (Imaging)idIn;
-    imOut = (Imaging)idOut;
+    if (!PyCapsule_IsValid(i0, IMAGING_MAGIC) ||
+        !PyCapsule_IsValid(i1, IMAGING_MAGIC)) {
+        PyErr_Format(PyExc_TypeError, "Expected '%s' Capsule", IMAGING_MAGIC);
+        return NULL;
+    }
 
-    result = pyCMSdoTransform(im, imOut, self->transform);
+    im = (Imaging)PyCapsule_GetPointer(i0, IMAGING_MAGIC);
+    imOut = (Imaging)PyCapsule_GetPointer(i1, IMAGING_MAGIC);
 
-    return Py_BuildValue("i", result);
+    return Py_BuildValue("i", pyCMSdoTransform(im, imOut, self->transform));
 }
 
 /* -------------------------------------------------------------------- */
diff --git a/src/_imagingft.c b/src/_imagingft.c
index 8bef45baf..7f2464124 100644
--- a/src/_imagingft.c
+++ b/src/_imagingft.c
@@ -830,7 +830,6 @@ font_render(FontObject *self, PyObject *args) {
     unsigned char convert_scale;    /* scale factor for non-8bpp bitmaps */
     PyObject *image;
     Imaging im;
-    Py_ssize_t id;
     int mask = 0;  /* is FT_LOAD_TARGET_MONO enabled? */
     int color = 0; /* is FT_LOAD_COLOR enabled? */
     float stroke_width = 0;
@@ -922,17 +921,13 @@ font_render(FontObject *self, PyObject *args) {
     width += ceil(stroke_width * 2 + x_start);
     height += ceil(stroke_width * 2 + y_start);
     image = PyObject_CallFunction(fill, "ii", width, height);
-    if (image == Py_None) {
-        PyMem_Del(glyph_info);
-        return Py_BuildValue("N(ii)", image, 0, 0);
-    } else if (image == NULL) {
+    if (image == NULL) {
         PyMem_Del(glyph_info);
         return NULL;
     }
-    PyObject *imageId = PyObject_GetAttrString(image, "id");
-    id = PyLong_AsSsize_t(imageId);
-    Py_XDECREF(imageId);
-    im = (Imaging)id;
+    PyObject *imagePtr = PyObject_GetAttrString(image, "ptr");
+    im = (Imaging)PyCapsule_GetPointer(imagePtr, IMAGING_MAGIC);
+    Py_XDECREF(imagePtr);
 
     x_offset = round(x_offset - stroke_width);
     y_offset = round(y_offset - stroke_width);
diff --git a/src/_imagingmath.c b/src/_imagingmath.c
index 550a10903..dbe636707 100644
--- a/src/_imagingmath.c
+++ b/src/_imagingmath.c
@@ -23,6 +23,9 @@
 #define MAX_INT32 2147483647.0
 #define MIN_INT32 -2147483648.0
 
+#define MATH_FUNC_UNOP_MAGIC "Pillow Math unary func"
+#define MATH_FUNC_BINOP_MAGIC "Pillow Math binary func"
+
 #define UNOP(name, op, type)                   \
     void name(Imaging out, Imaging im1) {      \
         int x, y;                              \
@@ -168,15 +171,24 @@ _unop(PyObject *self, PyObject *args) {
     Imaging im1;
     void (*unop)(Imaging, Imaging);
 
-    Py_ssize_t op, i0, i1;
-    if (!PyArg_ParseTuple(args, "nnn", &op, &i0, &i1)) {
+    PyObject *op, *i0, *i1;
+    if (!PyArg_ParseTuple(args, "OOO", &op, &i0, &i1)) {
         return NULL;
     }
 
-    out = (Imaging)i0;
-    im1 = (Imaging)i1;
+    if (!PyCapsule_IsValid(op, MATH_FUNC_UNOP_MAGIC)) {
+        PyErr_Format(PyExc_TypeError, "Expected '%s' Capsule", MATH_FUNC_UNOP_MAGIC);
+        return NULL;
+    }
+    if (!PyCapsule_IsValid(i0, IMAGING_MAGIC) ||
+        !PyCapsule_IsValid(i1, IMAGING_MAGIC)) {
+        PyErr_Format(PyExc_TypeError, "Expected '%s' Capsule", IMAGING_MAGIC);
+        return NULL;
+    }
 
-    unop = (void *)op;
+    unop = (void *)PyCapsule_GetPointer(op, MATH_FUNC_UNOP_MAGIC);
+    out = (Imaging)PyCapsule_GetPointer(i0, IMAGING_MAGIC);
+    im1 = (Imaging)PyCapsule_GetPointer(i1, IMAGING_MAGIC);
 
     unop(out, im1);
 
@@ -191,16 +203,26 @@ _binop(PyObject *self, PyObject *args) {
     Imaging im2;
     void (*binop)(Imaging, Imaging, Imaging);
 
-    Py_ssize_t op, i0, i1, i2;
-    if (!PyArg_ParseTuple(args, "nnnn", &op, &i0, &i1, &i2)) {
+    PyObject *op, *i0, *i1, *i2;
+    if (!PyArg_ParseTuple(args, "OOOO", &op, &i0, &i1, &i2)) {
         return NULL;
     }
 
-    out = (Imaging)i0;
-    im1 = (Imaging)i1;
-    im2 = (Imaging)i2;
+    if (!PyCapsule_IsValid(op, MATH_FUNC_BINOP_MAGIC)) {
+        PyErr_Format(PyExc_TypeError, "Expected '%s' Capsule", MATH_FUNC_BINOP_MAGIC);
+        return NULL;
+    }
+    if (!PyCapsule_IsValid(i0, IMAGING_MAGIC) ||
+        !PyCapsule_IsValid(i1, IMAGING_MAGIC) ||
+        !PyCapsule_IsValid(i2, IMAGING_MAGIC)) {
+        PyErr_Format(PyExc_TypeError, "Expected '%s' Capsule", IMAGING_MAGIC);
+        return NULL;
+    }
 
-    binop = (void *)op;
+    binop = (void *)PyCapsule_GetPointer(op, MATH_FUNC_BINOP_MAGIC);
+    out = (Imaging)PyCapsule_GetPointer(i0, IMAGING_MAGIC);
+    im1 = (Imaging)PyCapsule_GetPointer(i1, IMAGING_MAGIC);
+    im2 = (Imaging)PyCapsule_GetPointer(i2, IMAGING_MAGIC);
 
     binop(out, im1, im2);
 
@@ -213,8 +235,17 @@ static PyMethodDef _functions[] = {
 };
 
 static void
-install(PyObject *d, char *name, void *value) {
-    PyObject *v = PyLong_FromSsize_t((Py_ssize_t)value);
+install_unary(PyObject *d, char *name, void *func) {
+    PyObject *v = PyCapsule_New(func, MATH_FUNC_UNOP_MAGIC, NULL);
+    if (!v || PyDict_SetItemString(d, name, v)) {
+        PyErr_Clear();
+    }
+    Py_XDECREF(v);
+}
+
+static void
+install_binary(PyObject *d, char *name, void *func) {
+    PyObject *v = PyCapsule_New(func, MATH_FUNC_BINOP_MAGIC, NULL);
     if (!v || PyDict_SetItemString(d, name, v)) {
         PyErr_Clear();
     }
@@ -225,50 +256,50 @@ static int
 setup_module(PyObject *m) {
     PyObject *d = PyModule_GetDict(m);
 
-    install(d, "abs_I", abs_I);
-    install(d, "neg_I", neg_I);
-    install(d, "add_I", add_I);
-    install(d, "sub_I", sub_I);
-    install(d, "diff_I", diff_I);
-    install(d, "mul_I", mul_I);
-    install(d, "div_I", div_I);
-    install(d, "mod_I", mod_I);
-    install(d, "min_I", min_I);
-    install(d, "max_I", max_I);
-    install(d, "pow_I", pow_I);
+    install_unary(d, "abs_I", abs_I);
+    install_unary(d, "neg_I", neg_I);
+    install_binary(d, "add_I", add_I);
+    install_binary(d, "sub_I", sub_I);
+    install_binary(d, "diff_I", diff_I);
+    install_binary(d, "mul_I", mul_I);
+    install_binary(d, "div_I", div_I);
+    install_binary(d, "mod_I", mod_I);
+    install_binary(d, "min_I", min_I);
+    install_binary(d, "max_I", max_I);
+    install_binary(d, "pow_I", pow_I);
 
-    install(d, "invert_I", invert_I);
-    install(d, "and_I", and_I);
-    install(d, "or_I", or_I);
-    install(d, "xor_I", xor_I);
-    install(d, "lshift_I", lshift_I);
-    install(d, "rshift_I", rshift_I);
+    install_unary(d, "invert_I", invert_I);
+    install_binary(d, "and_I", and_I);
+    install_binary(d, "or_I", or_I);
+    install_binary(d, "xor_I", xor_I);
+    install_binary(d, "lshift_I", lshift_I);
+    install_binary(d, "rshift_I", rshift_I);
 
-    install(d, "eq_I", eq_I);
-    install(d, "ne_I", ne_I);
-    install(d, "lt_I", lt_I);
-    install(d, "le_I", le_I);
-    install(d, "gt_I", gt_I);
-    install(d, "ge_I", ge_I);
+    install_binary(d, "eq_I", eq_I);
+    install_binary(d, "ne_I", ne_I);
+    install_binary(d, "lt_I", lt_I);
+    install_binary(d, "le_I", le_I);
+    install_binary(d, "gt_I", gt_I);
+    install_binary(d, "ge_I", ge_I);
 
-    install(d, "abs_F", abs_F);
-    install(d, "neg_F", neg_F);
-    install(d, "add_F", add_F);
-    install(d, "sub_F", sub_F);
-    install(d, "diff_F", diff_F);
-    install(d, "mul_F", mul_F);
-    install(d, "div_F", div_F);
-    install(d, "mod_F", mod_F);
-    install(d, "min_F", min_F);
-    install(d, "max_F", max_F);
-    install(d, "pow_F", pow_F);
+    install_unary(d, "abs_F", abs_F);
+    install_unary(d, "neg_F", neg_F);
+    install_binary(d, "add_F", add_F);
+    install_binary(d, "sub_F", sub_F);
+    install_binary(d, "diff_F", diff_F);
+    install_binary(d, "mul_F", mul_F);
+    install_binary(d, "div_F", div_F);
+    install_binary(d, "mod_F", mod_F);
+    install_binary(d, "min_F", min_F);
+    install_binary(d, "max_F", max_F);
+    install_binary(d, "pow_F", pow_F);
 
-    install(d, "eq_F", eq_F);
-    install(d, "ne_F", ne_F);
-    install(d, "lt_F", lt_F);
-    install(d, "le_F", le_F);
-    install(d, "gt_F", gt_F);
-    install(d, "ge_F", ge_F);
+    install_binary(d, "eq_F", eq_F);
+    install_binary(d, "ne_F", ne_F);
+    install_binary(d, "lt_F", lt_F);
+    install_binary(d, "le_F", le_F);
+    install_binary(d, "gt_F", gt_F);
+    install_binary(d, "ge_F", ge_F);
 
     return 0;
 }
diff --git a/src/_imagingmorph.c b/src/_imagingmorph.c
index 614dfbe7f..b763e3a6f 100644
--- a/src/_imagingmorph.c
+++ b/src/_imagingmorph.c
@@ -11,7 +11,6 @@
  * See the README file for information on usage and redistribution.
  */
 
-#include "Python.h"
 #include "libImaging/Imaging.h"
 
 #define LUT_SIZE (1 << 9)
@@ -30,43 +29,36 @@
 static PyObject *
 apply(PyObject *self, PyObject *args) {
     const char *lut;
-    PyObject *py_lut;
-    Py_ssize_t lut_len, i0, i1;
+    Py_ssize_t lut_len;
+    PyObject *i0, *i1;
     Imaging imgin, imgout;
     int width, height;
     int row_idx, col_idx;
     UINT8 **inrows, **outrows;
     int num_changed_pixels = 0;
 
-    if (!PyArg_ParseTuple(args, "Onn", &py_lut, &i0, &i1)) {
-        PyErr_SetString(PyExc_RuntimeError, "Argument parsing problem");
+    if (!PyArg_ParseTuple(args, "s#OO", &lut, &lut_len, &i0, &i1)) {
         return NULL;
     }
 
-    if (!PyBytes_Check(py_lut)) {
-        PyErr_SetString(PyExc_RuntimeError, "The morphology LUT is not a bytes object");
-        return NULL;
-    }
-
-    lut_len = PyBytes_Size(py_lut);
-
     if (lut_len < LUT_SIZE) {
         PyErr_SetString(PyExc_RuntimeError, "The morphology LUT has the wrong size");
         return NULL;
     }
 
-    lut = PyBytes_AsString(py_lut);
+    if (!PyCapsule_IsValid(i0, IMAGING_MAGIC) ||
+        !PyCapsule_IsValid(i1, IMAGING_MAGIC)) {
+        PyErr_Format(PyExc_TypeError, "Expected '%s' Capsule", IMAGING_MAGIC);
+        return NULL;
+    }
 
-    imgin = (Imaging)i0;
-    imgout = (Imaging)i1;
+    imgin = (Imaging)PyCapsule_GetPointer(i0, IMAGING_MAGIC);
+    imgout = (Imaging)PyCapsule_GetPointer(i1, IMAGING_MAGIC);
     width = imgin->xsize;
     height = imgin->ysize;
 
-    if (imgin->type != IMAGING_TYPE_UINT8 || imgin->bands != 1) {
-        PyErr_SetString(PyExc_RuntimeError, "Unsupported image type");
-        return NULL;
-    }
-    if (imgout->type != IMAGING_TYPE_UINT8 || imgout->bands != 1) {
+    if (imgin->type != IMAGING_TYPE_UINT8 || imgin->bands != 1 ||
+        imgout->type != IMAGING_TYPE_UINT8 || imgout->bands != 1) {
         PyErr_SetString(PyExc_RuntimeError, "Unsupported image type");
         return NULL;
     }
@@ -129,46 +121,39 @@ apply(PyObject *self, PyObject *args) {
 static PyObject *
 match(PyObject *self, PyObject *args) {
     const char *lut;
-    PyObject *py_lut;
-    Py_ssize_t lut_len, i0;
+    Py_ssize_t lut_len;
+    PyObject *i0;
     Imaging imgin;
     int width, height;
     int row_idx, col_idx;
     UINT8 **inrows;
-    PyObject *ret = PyList_New(0);
-    if (ret == NULL) {
+
+    if (!PyArg_ParseTuple(args, "s#O", &lut, &lut_len, &i0)) {
         return NULL;
     }
 
-    if (!PyArg_ParseTuple(args, "On", &py_lut, &i0)) {
-        Py_DECREF(ret);
-        PyErr_SetString(PyExc_RuntimeError, "Argument parsing problem");
-        return NULL;
-    }
-
-    if (!PyBytes_Check(py_lut)) {
-        Py_DECREF(ret);
-        PyErr_SetString(PyExc_RuntimeError, "The morphology LUT is not a bytes object");
-        return NULL;
-    }
-
-    lut_len = PyBytes_Size(py_lut);
-
     if (lut_len < LUT_SIZE) {
-        Py_DECREF(ret);
         PyErr_SetString(PyExc_RuntimeError, "The morphology LUT has the wrong size");
         return NULL;
     }
 
-    lut = PyBytes_AsString(py_lut);
-    imgin = (Imaging)i0;
+    if (!PyCapsule_IsValid(i0, IMAGING_MAGIC)) {
+        PyErr_Format(PyExc_TypeError, "Expected '%s' Capsule", IMAGING_MAGIC);
+        return NULL;
+    }
+
+    imgin = (Imaging)PyCapsule_GetPointer(i0, IMAGING_MAGIC);
 
     if (imgin->type != IMAGING_TYPE_UINT8 || imgin->bands != 1) {
-        Py_DECREF(ret);
         PyErr_SetString(PyExc_RuntimeError, "Unsupported image type");
         return NULL;
     }
 
+    PyObject *ret = PyList_New(0);
+    if (ret == NULL) {
+        return NULL;
+    }
+
     inrows = imgin->image8;
     width = imgin->xsize;
     height = imgin->ysize;
@@ -215,26 +200,31 @@ match(PyObject *self, PyObject *args) {
 */
 static PyObject *
 get_on_pixels(PyObject *self, PyObject *args) {
-    Py_ssize_t i0;
+    PyObject *i0;
     Imaging img;
     UINT8 **rows;
     int row_idx, col_idx;
     int width, height;
+
+    if (!PyArg_ParseTuple(args, "O", &i0)) {
+        return NULL;
+    }
+
+    if (!PyCapsule_IsValid(i0, IMAGING_MAGIC)) {
+        PyErr_Format(PyExc_TypeError, "Expected '%s' Capsule", IMAGING_MAGIC);
+        return NULL;
+    }
+
+    img = (Imaging)PyCapsule_GetPointer(i0, IMAGING_MAGIC);
+    rows = img->image8;
+    width = img->xsize;
+    height = img->ysize;
+
     PyObject *ret = PyList_New(0);
     if (ret == NULL) {
         return NULL;
     }
 
-    if (!PyArg_ParseTuple(args, "n", &i0)) {
-        Py_DECREF(ret);
-        PyErr_SetString(PyExc_RuntimeError, "Argument parsing problem");
-        return NULL;
-    }
-    img = (Imaging)i0;
-    rows = img->image8;
-    width = img->xsize;
-    height = img->ysize;
-
     for (row_idx = 0; row_idx < height; row_idx++) {
         UINT8 *row = rows[row_idx];
         for (col_idx = 0; col_idx < width; col_idx++) {
diff --git a/src/libImaging/Filter.c b/src/libImaging/Filter.c
index fbd6b425f..7b7b2e429 100644
--- a/src/libImaging/Filter.c
+++ b/src/libImaging/Filter.c
@@ -26,6 +26,8 @@
 
 #include "Imaging.h"
 
+#define ROUND_UP(f) ((int)((f) >= 0.0 ? (f) + 0.5F : (f) - 0.5F))
+
 static inline UINT8
 clip8(float in) {
     if (in <= 0.0) {
@@ -105,6 +107,22 @@ ImagingExpand(Imaging imIn, int xmargin, int ymargin) {
     return imOut;
 }
 
+float
+kernel_i16(int size, UINT8 *in0, int x, const float *kernel, int bigendian) {
+    int i;
+    float result = 0;
+    int half_size = (size - 1) / 2;
+    for (i = 0; i < size; i++) {
+        int x1 = x + i - half_size;
+        result += _i2f(
+                      in0[x1 * 2 + (bigendian ? 1 : 0)] +
+                      (in0[x1 * 2 + (bigendian ? 0 : 1)] >> 8)
+                  ) *
+                  kernel[i];
+    }
+    return result;
+}
+
 void
 ImagingFilter3x3(Imaging imOut, Imaging im, const float *kernel, float offset) {
 #define KERNEL1x3(in0, x, kernel, d)                               \
@@ -135,6 +153,16 @@ ImagingFilter3x3(Imaging imOut, Imaging im, const float *kernel, float offset) {
                 out[x] = in0[x];
             }
         } else {
+            int bigendian = 0;
+            if (im->type == IMAGING_TYPE_SPECIAL) {
+                if (strcmp(im->mode, "I;16B") == 0
+#ifdef WORDS_BIGENDIAN
+                    || strcmp(im->mode, "I;16N") == 0
+#endif
+                ) {
+                    bigendian = 1;
+                }
+            }
             for (y = 1; y < im->ysize - 1; y++) {
                 UINT8 *in_1 = (UINT8 *)im->image[y - 1];
                 UINT8 *in0 = (UINT8 *)im->image[y];
@@ -142,14 +170,31 @@ ImagingFilter3x3(Imaging imOut, Imaging im, const float *kernel, float offset) {
                 UINT8 *out = (UINT8 *)imOut->image[y];
 
                 out[0] = in0[0];
+                if (im->type == IMAGING_TYPE_SPECIAL) {
+                    out[1] = in0[1];
+                }
                 for (x = 1; x < im->xsize - 1; x++) {
                     float ss = offset;
-                    ss += KERNEL1x3(in1, x, &kernel[0], 1);
-                    ss += KERNEL1x3(in0, x, &kernel[3], 1);
-                    ss += KERNEL1x3(in_1, x, &kernel[6], 1);
-                    out[x] = clip8(ss);
+                    if (im->type == IMAGING_TYPE_SPECIAL) {
+                        ss += kernel_i16(3, in1, x, &kernel[0], bigendian);
+                        ss += kernel_i16(3, in0, x, &kernel[3], bigendian);
+                        ss += kernel_i16(3, in_1, x, &kernel[6], bigendian);
+                        int ss_int = ROUND_UP(ss);
+                        out[x * 2 + (bigendian ? 1 : 0)] = clip8(ss_int % 256);
+                        out[x * 2 + (bigendian ? 0 : 1)] = clip8(ss_int >> 8);
+                    } else {
+                        ss += KERNEL1x3(in1, x, &kernel[0], 1);
+                        ss += KERNEL1x3(in0, x, &kernel[3], 1);
+                        ss += KERNEL1x3(in_1, x, &kernel[6], 1);
+                        out[x] = clip8(ss);
+                    }
+                }
+                if (im->type == IMAGING_TYPE_SPECIAL) {
+                    out[x * 2] = in0[x * 2];
+                    out[x * 2 + 1] = in0[x * 2 + 1];
+                } else {
+                    out[x] = in0[x];
                 }
-                out[x] = in0[x];
             }
         }
     } else {
@@ -261,6 +306,16 @@ ImagingFilter5x5(Imaging imOut, Imaging im, const float *kernel, float offset) {
                 out[x + 1] = in0[x + 1];
             }
         } else {
+            int bigendian = 0;
+            if (im->type == IMAGING_TYPE_SPECIAL) {
+                if (strcmp(im->mode, "I;16B") == 0
+#ifdef WORDS_BIGENDIAN
+                    || strcmp(im->mode, "I;16N") == 0
+#endif
+                ) {
+                    bigendian = 1;
+                }
+            }
             for (y = 2; y < im->ysize - 2; y++) {
                 UINT8 *in_2 = (UINT8 *)im->image[y - 2];
                 UINT8 *in_1 = (UINT8 *)im->image[y - 1];
@@ -271,17 +326,39 @@ ImagingFilter5x5(Imaging imOut, Imaging im, const float *kernel, float offset) {
 
                 out[0] = in0[0];
                 out[1] = in0[1];
+                if (im->type == IMAGING_TYPE_SPECIAL) {
+                    out[2] = in0[2];
+                    out[3] = in0[3];
+                }
                 for (x = 2; x < im->xsize - 2; x++) {
                     float ss = offset;
-                    ss += KERNEL1x5(in2, x, &kernel[0], 1);
-                    ss += KERNEL1x5(in1, x, &kernel[5], 1);
-                    ss += KERNEL1x5(in0, x, &kernel[10], 1);
-                    ss += KERNEL1x5(in_1, x, &kernel[15], 1);
-                    ss += KERNEL1x5(in_2, x, &kernel[20], 1);
-                    out[x] = clip8(ss);
+                    if (im->type == IMAGING_TYPE_SPECIAL) {
+                        ss += kernel_i16(5, in2, x, &kernel[0], bigendian);
+                        ss += kernel_i16(5, in1, x, &kernel[5], bigendian);
+                        ss += kernel_i16(5, in0, x, &kernel[10], bigendian);
+                        ss += kernel_i16(5, in_1, x, &kernel[15], bigendian);
+                        ss += kernel_i16(5, in_2, x, &kernel[20], bigendian);
+                        int ss_int = ROUND_UP(ss);
+                        out[x * 2 + (bigendian ? 1 : 0)] = clip8(ss_int % 256);
+                        out[x * 2 + (bigendian ? 0 : 1)] = clip8(ss_int >> 8);
+                    } else {
+                        ss += KERNEL1x5(in2, x, &kernel[0], 1);
+                        ss += KERNEL1x5(in1, x, &kernel[5], 1);
+                        ss += KERNEL1x5(in0, x, &kernel[10], 1);
+                        ss += KERNEL1x5(in_1, x, &kernel[15], 1);
+                        ss += KERNEL1x5(in_2, x, &kernel[20], 1);
+                        out[x] = clip8(ss);
+                    }
+                }
+                if (im->type == IMAGING_TYPE_SPECIAL) {
+                    out[x * 2 + 0] = in0[x * 2 + 0];
+                    out[x * 2 + 1] = in0[x * 2 + 1];
+                    out[x * 2 + 2] = in0[x * 2 + 2];
+                    out[x * 2 + 3] = in0[x * 2 + 3];
+                } else {
+                    out[x + 0] = in0[x + 0];
+                    out[x + 1] = in0[x + 1];
                 }
-                out[x + 0] = in0[x + 0];
-                out[x + 1] = in0[x + 1];
             }
         }
     } else {
@@ -383,7 +460,8 @@ ImagingFilter(Imaging im, int xsize, int ysize, const FLOAT32 *kernel, FLOAT32 o
     Imaging imOut;
     ImagingSectionCookie cookie;
 
-    if (im->type != IMAGING_TYPE_UINT8 && im->type != IMAGING_TYPE_INT32) {
+    if (im->type == IMAGING_TYPE_FLOAT32 ||
+        (im->type == IMAGING_TYPE_SPECIAL && im->bands != 1)) {
         return (Imaging)ImagingError_ModeError();
     }
 
diff --git a/src/libImaging/ImPlatform.h b/src/libImaging/ImPlatform.h
index f6e7fb6b9..c9b7e43b4 100644
--- a/src/libImaging/ImPlatform.h
+++ b/src/libImaging/ImPlatform.h
@@ -7,6 +7,7 @@
  * Copyright (c) Fredrik Lundh 1995-2003.
  */
 
+#define PY_SSIZE_T_CLEAN
 #include "Python.h"
 
 /* Check that we have an ANSI compliant compiler */
diff --git a/src/libImaging/Imaging.h b/src/libImaging/Imaging.h
index 321dce988..31052c68a 100644
--- a/src/libImaging/Imaging.h
+++ b/src/libImaging/Imaging.h
@@ -60,8 +60,8 @@ typedef struct ImagingHistogramInstance *ImagingHistogram;
 typedef struct ImagingOutlineInstance *ImagingOutline;
 typedef struct ImagingPaletteInstance *ImagingPalette;
 
-/* handle magics (used with PyCObject). */
-#define IMAGING_MAGIC "PIL Imaging"
+/* handle magics (used with PyCapsule). */
+#define IMAGING_MAGIC "Pillow Imaging"
 
 /* pixel types */
 #define IMAGING_TYPE_UINT8 0
diff --git a/src/libImaging/QuantOctree.c b/src/libImaging/QuantOctree.c
index 7e02ebf65..ec60b214e 100644
--- a/src/libImaging/QuantOctree.c
+++ b/src/libImaging/QuantOctree.c
@@ -188,7 +188,7 @@ create_sorted_color_palette(const ColorCube cube) {
         buckets,
         cube->size,
         sizeof(struct _ColorBucket),
-        (int (*)(void const *, void const *)) & compare_bucket_count
+        (int (*)(void const *, void const *))&compare_bucket_count
     );
 
     return buckets;
diff --git a/src/libImaging/TiffDecode.c b/src/libImaging/TiffDecode.c
index 18a54f633..e4da9162d 100644
--- a/src/libImaging/TiffDecode.c
+++ b/src/libImaging/TiffDecode.c
@@ -780,7 +780,7 @@ ImagingLibTiffDecode(
 decode_err:
     // TIFFClose in libtiff calls tif_closeproc and TIFFCleanup
     if (clientstate->fp) {
-        // Pillow will manage the closing of the file rather than libtiff
+        // Python will manage the closing of the file rather than libtiff
         // So only call TIFFCleanup
         TIFFCleanup(tiff);
     } else {
@@ -1008,7 +1008,17 @@ ImagingLibTiffEncode(Imaging im, ImagingCodecState state, UINT8 *buffer, int byt
                 ) == -1) {
                 TRACE(("Encode Error, row %d\n", state->y));
                 state->errcode = IMAGING_CODEC_BROKEN;
-                TIFFClose(tiff);
+
+                // TIFFClose in libtiff calls tif_closeproc and TIFFCleanup
+                if (clientstate->fp) {
+                    // Python will manage the closing of the file rather than libtiff
+                    // So only call TIFFCleanup
+                    TIFFCleanup(tiff);
+                } else {
+                    // When tif_closeproc refers to our custom _tiffCloseProc though,
+                    // that is fine, as it does not close the file
+                    TIFFClose(tiff);
+                }
                 if (!clientstate->fp) {
                     free(clientstate->data);
                 }
@@ -1025,14 +1035,22 @@ ImagingLibTiffEncode(Imaging im, ImagingCodecState state, UINT8 *buffer, int byt
                 TRACE(("Error flushing the tiff"));
                 // likely reason is memory.
                 state->errcode = IMAGING_CODEC_MEMORY;
-                TIFFClose(tiff);
+                if (clientstate->fp) {
+                    TIFFCleanup(tiff);
+                } else {
+                    TIFFClose(tiff);
+                }
                 if (!clientstate->fp) {
                     free(clientstate->data);
                 }
                 return -1;
             }
             TRACE(("Closing \n"));
-            TIFFClose(tiff);
+            if (clientstate->fp) {
+                TIFFCleanup(tiff);
+            } else {
+                TIFFClose(tiff);
+            }
             // reset the clientstate metadata to use it to read out the buffer.
             clientstate->loc = 0;
             clientstate->size = clientstate->eof;  // redundant?