python - Conversion from CMYK to RGB with Pillow is different from that of Photoshop

Question

I need to convert an image from CMYK to RGB in python. I used Pillow in this way:

img = Image.open('in.jpg')
img = img.convert('RGB')
img.save('out.jpg')

The code works, but if I convert the same image with Photoshop I have a different result as shown below:-

The only operation done in photoshop is to change method from CMYK to RGB. Why there is this difference between the two RGB images? It can be a color profile problem?

Answer 1

SOLVED

The problem is that Pillow does not know the input ICC profile, while photoshop had one set as default.

Photoshop use for

CMYK: U.S. Web Coated (SWOP) v2

RGB: sRGB IEC61966-2.1

So I've solved in this way:

img = Image.open('in.jpg')
img = ImageCms.profileToProfile(img, 'USWebCoatedSWOP.icc', 'sRGB Color Space Profile.icm', renderingIntent=0, outputMode='RGB')
img.save('out.jpg', quality=100)

---

On Windows the profiles can be found (if installed) in these folders:

C:WindowsSystem32spooldriverscolorUSWebCoatedSWOP.icc
C:Program Files (x86)Common FilesAdobeColorProfilesRecommendedUSWebCoatedSWOP.icc
C:Program Files (x86)AdobeAcrobat DCResourceColorProfilesRecommendedUSWebCoatedSWOP.icc

C:WindowsSystem32spooldriverscolorsRGB Color Space Profile.icm
C:Program Files (x86)Common FilesAdobeColorProfilesRecommendedsRGB Color Space Profile.icm
C:Program Files (x86)AdobeAcrobat DCResourceColorProfilesRecommendedsRGB Color Space Profile.icm