diff --git a/setup.py b/setup.py
index e4ff5fcd9c4..d75560151c6 100644
--- a/setup.py
+++ b/setup.py
@@ -999,7 +999,7 @@ def debug_build():
 ext_modules = [
     Extension("PIL._imaging", files, libraries=["pil_imaging_mode"]),
     Extension("PIL._imagingft", ["src/_imagingft.c"], libraries=["pil_imaging_mode"]),
-    Extension("PIL._imagingcms", ["src/_imagingcms.c"]),
+    Extension("PIL._imagingcms", ["src/_imagingcms.c"], libraries=["pil_imaging_mode"]),
     Extension("PIL._webp", ["src/_webp.c"], libraries=["pil_imaging_mode"]),
     Extension("PIL._imagingtk", ["src/_imagingtk.c", "src/Tk/tkImaging.c"]),
     Extension("PIL._imagingmath", ["src/_imagingmath.c"]),
diff --git a/src/_imagingcms.c b/src/_imagingcms.c
index bafe787a743..70513b21942 100644
--- a/src/_imagingcms.c
+++ b/src/_imagingcms.c
@@ -212,32 +212,39 @@ cms_transform_dealloc(CmsTransformObject *self) {
 /* internal functions */
 
 static cmsUInt32Number
-findLCMStype(char *PILmode) {
-    if (strcmp(PILmode, "RGB") == 0 || strcmp(PILmode, "RGBA") == 0 ||
-        strcmp(PILmode, "RGBX") == 0) {
-        return TYPE_RGBA_8;
-    }
-    if (strcmp(PILmode, "RGBA;16B") == 0) {
+findLCMStype(const char * const mode_name) {
+    const ModeID mode = findModeID(mode_name);
+    switch (mode) {
+        case IMAGING_MODE_RGB:
+        case IMAGING_MODE_RGBA:
+        case IMAGING_MODE_RGBX:
+            return TYPE_RGBA_8;
+        case IMAGING_MODE_CMYK:
+            return TYPE_CMYK_8;
+        case IMAGING_MODE_I_16:
+        case IMAGING_MODE_I_16L:
+            return TYPE_GRAY_16;
+        case IMAGING_MODE_I_16B:
+            return TYPE_GRAY_16_SE;
+        case IMAGING_MODE_YCbCr:
+            return TYPE_YCbCr_8;
+        case IMAGING_MODE_LAB:
+            // LabX equivalent like ALab, but not reversed -- no #define in lcms2
+            return (COLORSPACE_SH(PT_LabV2) | CHANNELS_SH(3) | BYTES_SH(1) | EXTRA_SH(1));
+    }
+    // The following modes are not valid PIL Image modes.
+    if (strcmp(mode_name, "RGBA;16B") == 0) {
         return TYPE_RGBA_16;
     }
-    if (strcmp(PILmode, "CMYK") == 0) {
-        return TYPE_CMYK_8;
-    }
-    if (strcmp(PILmode, "I;16") == 0 || strcmp(PILmode, "I;16L") == 0 ||
-        strcmp(PILmode, "L;16") == 0) {
+    if (strcmp(mode_name, "L;16") == 0) {
         return TYPE_GRAY_16;
     }
-    if (strcmp(PILmode, "I;16B") == 0 || strcmp(PILmode, "L;16B") == 0) {
+    if (strcmp(mode_name, "L;16B") == 0) {
         return TYPE_GRAY_16_SE;
     }
-    if (strcmp(PILmode, "YCbCr") == 0 || strcmp(PILmode, "YCCA") == 0 ||
-        strcmp(PILmode, "YCC") == 0) {
+    if (strcmp(mode_name, "YCCA") == 0 || strcmp(mode_name, "YCC") == 0) {
         return TYPE_YCbCr_8;
     }
-    if (strcmp(PILmode, "LAB") == 0) {
-        // LabX equivalent like ALab, but not reversed -- no #define in lcms2
-        return (COLORSPACE_SH(PT_LabV2) | CHANNELS_SH(3) | BYTES_SH(1) | EXTRA_SH(1));
-    }
     /* presume "1" or "L" by default */
     return TYPE_GRAY_8;
 }