问题
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?
回答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:\Windows\System32\spool\drivers\color\USWebCoatedSWOP.icc
C:\Program Files (x86)\Common Files\Adobe\Color\Profiles\Recommended\USWebCoatedSWOP.icc
C:\Program Files (x86)\Adobe\Acrobat DC\Resource\Color\Profiles\Recommended\USWebCoatedSWOP.icc
C:\Windows\System32\spool\drivers\color\sRGB Color Space Profile.icm
C:\Program Files (x86)\Common Files\Adobe\Color\Profiles\Recommended\sRGB Color Space Profile.icm
C:\Program Files (x86)\Adobe\Acrobat DC\Resource\Color\Profiles\Recommended\sRGB Color Space Profile.icm
来源：https://stackoverflow.com/questions/38855022/conversion-from-cmyk-to-rgb-with-pillow-is-different-from-that-of-photoshop