Pillow: Why does Pillow invert the color of a CMYK image when converting to PDF?

[vinodMS]

What did you do?

Using PIL to open a JPEG(CMYK) and then save it as PDF

What did you expect to happen?

A PDF with CMYK image.

What actually happened?

A PDF with CMYK image but the colors are inverted.

What are your OS, Python and Pillow versions?

• OS: Mac OS V 10.15.6
• Python: 3.7.6
• Pillow: 6.2.2

from PIL import Image, ImageOps

image = Image.open('door.jpg')
image.save(
  'output.pdf',
  resolution=180.0,
  quality=100
)

input and output image

Note: I tried converting the image to RGB prior to saving it as PDF and it works as intended. But since the PDF is meant for printing purpose, I need the image to be in CMYK.

Since I did not get an answer on Stackoverflow and it does seem like either a limitation in Pillow or perhaps not documented, i'm creating a ticket here.

[hugovk]

For reference, the Stack Overflow question:

• https://stackoverflow.com/q/63237829/724176

[radarhere]

Hi. I've created PR #4866 to fix this bug.

You haven't provided us your original CMYK image, so if you could test it and confirm that it solves your situation, that would be good.

[vinodMS]

Hi, thanks for the quick fix, I confirm that this PR fixes the issue I encountered.

[hugovk]

@vinodMS Thank you for the report, and for testing the PR!

@radarhere Thank you for the PR, merged!