diff --git a/src/libImaging/Arrow.c b/src/libImaging/Arrow.c
index d2ed10f0a..d00db3cc6 100644
--- a/src/libImaging/Arrow.c
+++ b/src/libImaging/Arrow.c
@@ -73,10 +73,10 @@ image_band_json(Imaging im) {
         json,
         len,
         format,
-        im->band_names[0],
-        im->band_names[1],
-        im->band_names[2],
-        im->band_names[3]
+        im->modedata->band_names[0],
+        im->modedata->band_names[1],
+        im->modedata->band_names[2],
+        im->modedata->band_names[3]
     );
     if (err < 0) {
         return NULL;
@@ -98,7 +98,7 @@ single_band_json(Imaging im) {
         return NULL;
     }
 
-    err = PyOS_snprintf(json, len, format, im->band_names[0]);
+    err = PyOS_snprintf(json, len, format, im->modedata->band_names[0]);
     if (err < 0) {
         return NULL;
     }
@@ -189,7 +189,7 @@ export_imaging_schema(Imaging im, struct ArrowSchema *schema) {
     int retval = 0;
     char *band_json;
 
-    if (strcmp(im->arrow_band_format, "") == 0) {
+    if (strcmp(im->modedata->arrow_band_format, "") == 0) {
         return IMAGING_ARROW_INCOMPATIBLE_MODE;
     }
 
@@ -199,7 +199,9 @@ export_imaging_schema(Imaging im, struct ArrowSchema *schema) {
     }
 
     if (im->bands == 1) {
-        retval = export_named_type(schema, im->arrow_band_format, im->band_names[0]);
+        retval = export_named_type(
+            schema, im->modedata->arrow_band_format, im->modedata->band_names[0]
+        );
         if (retval != 0) {
             return retval;
         }
@@ -221,7 +223,7 @@ export_imaging_schema(Imaging im, struct ArrowSchema *schema) {
     schema->children = calloc(1, sizeof(struct ArrowSchema *));
     schema->children[0] = (struct ArrowSchema *)calloc(1, sizeof(struct ArrowSchema));
     retval = export_named_type(
-        schema->children[0], im->arrow_band_format, getModeData(im->mode)->name
+        schema->children[0], im->modedata->arrow_band_format, im->modedata->name
     );
     if (retval != 0) {
         free(schema->children[0]);
@@ -405,7 +407,7 @@ err:
 
 int
 export_imaging_array(Imaging im, struct ArrowArray *array) {
-    if (strcmp(im->arrow_band_format, "") == 0) {
+    if (strcmp(im->modedata->arrow_band_format, "") == 0) {
         return IMAGING_ARROW_INCOMPATIBLE_MODE;
     }
 
diff --git a/src/libImaging/Imaging.h b/src/libImaging/Imaging.h
index f7049c892..db8f7b96e 100644
--- a/src/libImaging/Imaging.h
+++ b/src/libImaging/Imaging.h
@@ -79,11 +79,12 @@ typedef struct {
 
 struct ImagingMemoryInstance {
     /* Format */
-    ModeID mode; /* Image mode (IMAGING_MODE_*) */
-    int type;    /* Data type (IMAGING_TYPE_*) */
-    int depth;   /* Depth (ignored in this version) */
-    int bands;   /* Number of bands (1, 2, 3, or 4) */
-    int xsize;   /* Image dimension. */
+    ModeID mode;              /* Image mode (IMAGING_MODE_*) */
+    const ModeData *modedata; /* mode data struct */
+    int type;                 /* Data type (IMAGING_TYPE_*) */
+    int depth;                /* Depth (ignored in this version) */
+    int bands;                /* Number of bands (1, 2, 3, or 4) */
+    int xsize;                /* Image dimension. */
     int ysize;
 
     /* Colour palette (for "P" images only) */
@@ -105,9 +106,7 @@ struct ImagingMemoryInstance {
     void (*destroy)(Imaging im);
 
     /* arrow */
-    int refcount;              /* Number of arrow arrays that have been allocated */
-    char band_names[4][3];     /* names of bands, max 2 char + null terminator */
-    char arrow_band_format[2]; /* single character + null terminator */
+    int refcount; /* Number of arrow arrays that have been allocated */
 
     int read_only; /* flag for read-only. set for arrow borrowed arrays */
     PyObject *arrow_array_capsule; /* upstream arrow array source */
diff --git a/src/libImaging/Mode.c b/src/libImaging/Mode.c
index 7521f4cda..9d8ff9c98 100644
--- a/src/libImaging/Mode.c
+++ b/src/libImaging/Mode.c
@@ -9,18 +9,182 @@
 const ModeData MODES[] = {
     [IMAGING_MODE_UNKNOWN] = {""},
 
-    [IMAGING_MODE_1] = {"1"},         [IMAGING_MODE_CMYK] = {"CMYK"},
-    [IMAGING_MODE_F] = {"F"},         [IMAGING_MODE_HSV] = {"HSV"},
-    [IMAGING_MODE_I] = {"I"},         [IMAGING_MODE_L] = {"L"},
-    [IMAGING_MODE_LA] = {"LA"},       [IMAGING_MODE_LAB] = {"LAB"},
-    [IMAGING_MODE_La] = {"La"},       [IMAGING_MODE_P] = {"P"},
-    [IMAGING_MODE_PA] = {"PA"},       [IMAGING_MODE_RGB] = {"RGB"},
-    [IMAGING_MODE_RGBA] = {"RGBA"},   [IMAGING_MODE_RGBX] = {"RGBX"},
-    [IMAGING_MODE_RGBa] = {"RGBa"},   [IMAGING_MODE_YCbCr] = {"YCbCr"},
+    [IMAGING_MODE_1] =
+        {
+            .name = "1",
+            .arrow_band_format = "C",
+            .bands = 1,
+            .pixelsize = 1,
+            .band_names = {"1"},
+        },
+    [IMAGING_MODE_CMYK] =
+        {
+            .name = "CMYK",
+            .bands = 4,
+            .pixelsize = 4,
+            .arrow_band_format = "C",
+            .band_names = {"C", "M", "Y", "K"},
+        },
+    [IMAGING_MODE_F] =
+        {
+            .name = "F",
+            .bands = 1,
+            .pixelsize = 4,
+            .arrow_band_format = "f",
+            .band_names = {"F"},
+        },
+    [IMAGING_MODE_HSV] =
+        {
+            .name = "HSV",
+            .bands = 3,
+            .pixelsize = 4,
+            .arrow_band_format = "C",
+            .band_names = {"H", "S", "V", "X"},
+        },
+    [IMAGING_MODE_I] =
+        {
+            .name = "I",
+            .bands = 1,
+            .pixelsize = 4,
+            .arrow_band_format = "i",
+            .band_names = {"I"},
+        },
+    [IMAGING_MODE_L] =
+        {
+            .name = "L",
+            .bands = 1,
+            .pixelsize = 1,
+            .arrow_band_format = "C",
+            .band_names = {"L"},
+        },
+    [IMAGING_MODE_LA] =
+        {
+            .name = "LA",
+            .bands = 2,
+            .pixelsize = 4,
+            .arrow_band_format = "C",
+            .band_names = {"L", "X", "X", "A"},
+        },
+    [IMAGING_MODE_LAB] =
+        {
+            .name = "LAB",
+            .bands = 3,
+            .pixelsize = 4,
+            .arrow_band_format = "C",
+            .band_names = {"L", "a", "b", "X"},
+        },
+    [IMAGING_MODE_La] =
+        {
+            .name = "La",
+            .bands = 2,
+            .pixelsize = 4,
+            .arrow_band_format = "C",
+            .band_names = {"L", "X", "X", "a"},
+        },
+    [IMAGING_MODE_P] =
+        {
+            .name = "P",
+            .bands = 1,
+            .pixelsize = 1,
+            .arrow_band_format = "C",
+            .band_names = {"P"},
+        },
+    [IMAGING_MODE_PA] =
+        {
+            .name = "PA",
+            .bands = 2,
+            .pixelsize = 4,
+            .arrow_band_format = "C",
+            .band_names = {"P", "X", "X", "A"},
+        },
+    [IMAGING_MODE_RGB] =
+        {
+            .name = "RGB",
+            .bands = 3,
+            .pixelsize = 4,
+            .arrow_band_format = "C",
+            .band_names = {"R", "G", "B", "X"},
+        },
+    [IMAGING_MODE_RGBA] =
+        {
+            .name = "RGBA",
+            .bands = 4,
+            .pixelsize = 4,
+            .arrow_band_format = "C",
+            .band_names = {"R", "G", "B", "A"},
+        },
+    [IMAGING_MODE_RGBX] =
+        {
+            .name = "RGBX",
+            .bands = 4,
+            .pixelsize = 4,
+            .arrow_band_format = "C",
+            .band_names = {"R", "G", "B", "X"},
+        },
+    [IMAGING_MODE_RGBa] =
+        {
+            .name = "RGBa",
+            .bands = 4,
+            .pixelsize = 4,
+            .arrow_band_format = "C",
+            .band_names = {"R", "G", "B", "a"},
+        },
+    [IMAGING_MODE_YCbCr] =
+        {
+            .name = "YCbCr",
+            .bands = 3,
+            .pixelsize = 4,
+            .arrow_band_format = "C",
+            .band_names = {"Y", "Cb", "Cr", "X"},
+        },
 
-    [IMAGING_MODE_I_16] = {"I;16"},   [IMAGING_MODE_I_16L] = {"I;16L"},
-    [IMAGING_MODE_I_16B] = {"I;16B"}, [IMAGING_MODE_I_16N] = {"I;16N"},
-    [IMAGING_MODE_I_32L] = {"I;32L"}, [IMAGING_MODE_I_32B] = {"I;32B"},
+    [IMAGING_MODE_I_16] =
+        {
+            .name = "I;16",
+            .bands = 1,
+            .pixelsize = 2,
+            .arrow_band_format = "s",
+            .band_names = {"I"},
+        },
+    [IMAGING_MODE_I_16L] =
+        {
+            .name = "I;16L",
+            .bands = 1,
+            .pixelsize = 2,
+            .arrow_band_format = "s",
+            .band_names = {"I"},
+        },
+    [IMAGING_MODE_I_16B] =
+        {
+            .name = "I;16B",
+            .bands = 1,
+            .pixelsize = 2,
+            .arrow_band_format = "s",
+            .band_names = {"I"},
+        },
+    [IMAGING_MODE_I_16N] =
+        {
+            .name = "I;16N",
+            .bands = 1,
+            .pixelsize = 2,
+            .arrow_band_format = "s",
+            .band_names = {"I"},
+        },
+    [IMAGING_MODE_I_32L] =
+        {
+            .name = "I;32L",
+            .bands = 1,
+            .pixelsize = 4,
+            .arrow_band_format = "i",
+            .band_names = {"I"},
+        },
+    [IMAGING_MODE_I_32B] = {
+        .name = "I;32B",
+        .bands = 1,
+        .pixelsize = 4,
+        .arrow_band_format = "i",
+        .band_names = {"I"},
+    },
 };
 
 const ModeID
diff --git a/src/libImaging/Mode.h b/src/libImaging/Mode.h
index a3eb3d86d..4baf04319 100644
--- a/src/libImaging/Mode.h
+++ b/src/libImaging/Mode.h
@@ -31,6 +31,10 @@ typedef enum {
 
 typedef struct {
     const char *const name;
+    const char *const arrow_band_format;
+    const int bands;
+    const int pixelsize;
+    const char *band_names[4]; /* names of bands */
 } ModeData;
 
 const ModeID
diff --git a/src/libImaging/Storage.c b/src/libImaging/Storage.c
index c09062c92..f8c73988a 100644
--- a/src/libImaging/Storage.c
+++ b/src/libImaging/Storage.c
@@ -60,163 +60,70 @@ ImagingNewPrologueSubtype(const ModeID mode, int xsize, int ysize, int size) {
     im->ysize = ysize;
     im->refcount = 1;
     im->type = IMAGING_TYPE_UINT8;
-    strcpy(im->arrow_band_format, "C");
+    im->modedata = getModeData(mode);
+
+    im->bands = im->modedata->bands;
+    im->pixelsize = im->modedata->pixelsize;
+    im->linesize = xsize * im->pixelsize;
 
     if (mode == IMAGING_MODE_1) {
         /* 1-bit images */
-        im->bands = im->pixelsize = 1;
-        im->linesize = xsize;
-        strcpy(im->band_names[0], "1");
 
     } else if (mode == IMAGING_MODE_P) {
         /* 8-bit palette mapped images */
-        im->bands = im->pixelsize = 1;
-        im->linesize = xsize;
         im->palette = ImagingPaletteNew(IMAGING_MODE_RGB);
-        strcpy(im->band_names[0], "P");
 
     } else if (mode == IMAGING_MODE_PA) {
         /* 8-bit palette with alpha */
-        im->bands = 2;
-        im->pixelsize = 4; /* store in image32 memory */
-        im->linesize = xsize * 4;
         im->palette = ImagingPaletteNew(IMAGING_MODE_RGB);
-        strcpy(im->band_names[0], "P");
-        strcpy(im->band_names[1], "X");
-        strcpy(im->band_names[2], "X");
-        strcpy(im->band_names[3], "A");
 
     } else if (mode == IMAGING_MODE_L) {
         /* 8-bit grayscale (luminance) images */
-        im->bands = im->pixelsize = 1;
-        im->linesize = xsize;
-        strcpy(im->band_names[0], "L");
 
     } else if (mode == IMAGING_MODE_LA) {
         /* 8-bit grayscale (luminance) with alpha */
-        im->bands = 2;
-        im->pixelsize = 4; /* store in image32 memory */
-        im->linesize = xsize * 4;
-        strcpy(im->band_names[0], "L");
-        strcpy(im->band_names[1], "X");
-        strcpy(im->band_names[2], "X");
-        strcpy(im->band_names[3], "A");
 
     } else if (mode == IMAGING_MODE_La) {
         /* 8-bit grayscale (luminance) with premultiplied alpha */
-        im->bands = 2;
-        im->pixelsize = 4; /* store in image32 memory */
-        im->linesize = xsize * 4;
-        strcpy(im->band_names[0], "L");
-        strcpy(im->band_names[1], "X");
-        strcpy(im->band_names[2], "X");
-        strcpy(im->band_names[3], "a");
 
     } else if (mode == IMAGING_MODE_F) {
         /* 32-bit floating point images */
-        im->bands = 1;
-        im->pixelsize = 4;
-        im->linesize = xsize * 4;
         im->type = IMAGING_TYPE_FLOAT32;
-        strcpy(im->arrow_band_format, "f");
-        strcpy(im->band_names[0], "F");
 
     } else if (mode == IMAGING_MODE_I) {
         /* 32-bit integer images */
-        im->bands = 1;
-        im->pixelsize = 4;
-        im->linesize = xsize * 4;
         im->type = IMAGING_TYPE_INT32;
-        strcpy(im->arrow_band_format, "i");
-        strcpy(im->band_names[0], "I");
 
     } else if (isModeI16(mode)) {
         /* EXPERIMENTAL */
         /* 16-bit raw integer images */
-        im->bands = 1;
-        im->pixelsize = 2;
-        im->linesize = xsize * 2;
         im->type = IMAGING_TYPE_SPECIAL;
-        strcpy(im->arrow_band_format, "s");
-        strcpy(im->band_names[0], "I");
 
     } else if (mode == IMAGING_MODE_RGB) {
         /* 24-bit true colour images */
-        im->bands = 3;
-        im->pixelsize = 4;
-        im->linesize = xsize * 4;
-        strcpy(im->band_names[0], "R");
-        strcpy(im->band_names[1], "G");
-        strcpy(im->band_names[2], "B");
-        strcpy(im->band_names[3], "X");
 
     } else if (mode == IMAGING_MODE_RGBX) {
         /* 32-bit true colour images with padding */
-        im->bands = im->pixelsize = 4;
-        im->linesize = xsize * 4;
-        strcpy(im->band_names[0], "R");
-        strcpy(im->band_names[1], "G");
-        strcpy(im->band_names[2], "B");
-        strcpy(im->band_names[3], "X");
 
     } else if (mode == IMAGING_MODE_RGBA) {
         /* 32-bit true colour images with alpha */
-        im->bands = im->pixelsize = 4;
-        im->linesize = xsize * 4;
-        strcpy(im->band_names[0], "R");
-        strcpy(im->band_names[1], "G");
-        strcpy(im->band_names[2], "B");
-        strcpy(im->band_names[3], "A");
 
     } else if (mode == IMAGING_MODE_RGBa) {
         /* 32-bit true colour images with premultiplied alpha */
-        im->bands = im->pixelsize = 4;
-        im->linesize = xsize * 4;
-        strcpy(im->band_names[0], "R");
-        strcpy(im->band_names[1], "G");
-        strcpy(im->band_names[2], "B");
-        strcpy(im->band_names[3], "a");
 
     } else if (mode == IMAGING_MODE_CMYK) {
         /* 32-bit colour separation */
-        im->bands = im->pixelsize = 4;
-        im->linesize = xsize * 4;
-        strcpy(im->band_names[0], "C");
-        strcpy(im->band_names[1], "M");
-        strcpy(im->band_names[2], "Y");
-        strcpy(im->band_names[3], "K");
 
     } else if (mode == IMAGING_MODE_YCbCr) {
         /* 24-bit video format */
-        im->bands = 3;
-        im->pixelsize = 4;
-        im->linesize = xsize * 4;
-        strcpy(im->band_names[0], "Y");
-        strcpy(im->band_names[1], "Cb");
-        strcpy(im->band_names[2], "Cr");
-        strcpy(im->band_names[3], "X");
 
     } else if (mode == IMAGING_MODE_LAB) {
         /* 24-bit color, luminance, + 2 color channels */
         /* L is uint8, a,b are int8 */
-        im->bands = 3;
-        im->pixelsize = 4;
-        im->linesize = xsize * 4;
-        strcpy(im->band_names[0], "L");
-        strcpy(im->band_names[1], "a");
-        strcpy(im->band_names[2], "b");
-        strcpy(im->band_names[3], "X");
 
     } else if (mode == IMAGING_MODE_HSV) {
         /* 24-bit color, luminance, + 2 color channels */
         /* L is uint8, a,b are int8 */
-        im->bands = 3;
-        im->pixelsize = 4;
-        im->linesize = xsize * 4;
-        strcpy(im->band_names[0], "H");
-        strcpy(im->band_names[1], "S");
-        strcpy(im->band_names[2], "V");
-        strcpy(im->band_names[3], "X");
 
     } else {
         free(im);
@@ -699,8 +606,8 @@ ImagingNewArrow(
           && im->pixelsize == 4             // 4xchar* storage
           && im->bands >= 2)                // INT32 into any INT32 Storage mode
          ||                                 // (()||()) &&
-         (strcmp(schema->format, im->arrow_band_format) == 0  // same mode
-          && im->bands == 1))                                 // Single band match
+         (strcmp(schema->format, im->modedata->arrow_band_format) == 0  // same mode
+          && im->bands == 1))  // Single band match
         && pixels == external_array->length) {
         // one arrow element per, and it matches a pixelsize*char
         if (ImagingBorrowArrow(im, external_array, im->pixelsize, array_capsule)) {
@@ -712,11 +619,11 @@ ImagingNewArrow(
         && im->pixelsize == 4                // storage as 32 bpc
         && schema->n_children > 0            // make sure schema is well formed.
         && schema->children                  // make sure schema is well formed
-        && strcmp(schema->children[0]->format, "C") == 0  // Expected format
-        && strcmp(im->arrow_band_format, "C") == 0        // Expected Format
-        && pixels == external_array->length               // expected length
-        && external_array->n_children == 1                // array is well formed
-        && external_array->children                       // array is well formed
+        && strcmp(schema->children[0]->format, "C") == 0      // Expected format
+        && strcmp(im->modedata->arrow_band_format, "C") == 0  // Expected Format
+        && pixels == external_array->length                   // expected length
+        && external_array->n_children == 1                    // array is well formed
+        && external_array->children                           // array is well formed
         && 4 * pixels == external_array->children[0]->length) {
         // 4 up element of char into pixelsize == 4
         if (ImagingBorrowArrow(im, external_array, 1, array_capsule)) {
@@ -724,11 +631,11 @@ ImagingNewArrow(
         }
     }
     // Stored as [r,g,b,a,r,g,b,a,...]
-    if (strcmp(schema->format, "C") == 0            // uint8
-        && im->pixelsize == 4                       // storage as 32 bpc
-        && schema->n_children == 0                  // make sure schema is well formed.
-        && strcmp(im->arrow_band_format, "C") == 0  // expected format
-        && 4 * pixels == external_array->length) {  // expected length
+    if (strcmp(schema->format, "C") == 0  // uint8
+        && im->pixelsize == 4             // storage as 32 bpc
+        && schema->n_children == 0        // make sure schema is well formed.
+        && strcmp(im->modedata->arrow_band_format, "C") == 0  // expected format
+        && 4 * pixels == external_array->length) {            // expected length
         // single flat array, interleaved storage.
         if (ImagingBorrowArrow(im, external_array, 1, array_capsule)) {
             return im;