diff --git a/src/libImaging/Convert.c b/src/libImaging/Convert.c
index 7677a81f7..b08519d30 100644
--- a/src/libImaging/Convert.c
+++ b/src/libImaging/Convert.c
@@ -564,7 +564,7 @@ rgb2cmyk(UINT8 *out, const UINT8 *in, int xsize) {
     }
 }
 
-static void
+void
 cmyk2rgb(UINT8 *out, const UINT8 *in, int xsize) {
     int x, nk, tmp;
     for (x = 0; x < xsize; x++) {
diff --git a/src/libImaging/Convert.h b/src/libImaging/Convert.h
new file mode 100644
index 000000000..e688e3018
--- /dev/null
+++ b/src/libImaging/Convert.h
@@ -0,0 +1,2 @@
+extern void
+cmyk2rgb(UINT8 *out, const UINT8 *in, int xsize);
diff --git a/src/libImaging/Unpack.c b/src/libImaging/Unpack.c
index 6e86e7232..bef4bea66 100644
--- a/src/libImaging/Unpack.c
+++ b/src/libImaging/Unpack.c
@@ -31,6 +31,7 @@
  */
 
 #include "Imaging.h"
+#include "Convert.h"
 
 #define R 0
 #define G 1
@@ -813,20 +814,6 @@ ImagingUnpackXBGR(UINT8 *_out, const UINT8 *in, int pixels) {
     }
 }
 
-static void
-cmyk2rgb(UINT8 *_out, const UINT8 *in, int pixels) {
-    int i, nk, tmp;
-    for (i = 0; i < pixels; i++) {
-        nk = 255 - in[3];
-        _out[0] = CLIP8(nk - MULDIV255(in[0], nk, tmp));
-        _out[1] = CLIP8(nk - MULDIV255(in[1], nk, tmp));
-        _out[2] = CLIP8(nk - MULDIV255(in[2], nk, tmp));
-        _out[3] = 255;
-        _out += 4;
-        in += 4;
-    }
-}
-
 /* Unpack to "RGBA" image */
 
 static void