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Participant
February 15, 2019
Answered

Colour changing when converting artwork from CMYK to RGB

  • February 15, 2019
  • 2 replies
  • 2722 views

Hi, I've been experiencing an issue on Illustrator and Photoshop

Colours are changing when converting artwork from CMYK to RGB, which is not normal. Normally, colours would change if you convert from RGB to CMYK due to the gamut and not the other way around. When you switch from RGB to CMYK mode on Ai and Ps, blues, reds and greens would turn dull and washed out which is the, I get that. My problem is that I'm experiencing this exact result when I change the colour mode from CMYK to RGB.. this makes no sense to me.

I could use some help. Thank you

This topic has been closed for replies.
Correct answer JETalmage

Normally, colours would change if you convert from RGB to CMYK...My problem is that I'm experiencing [color shifs] when I change the colour mode from CMYK to RGB.. this makes no sense to me.

In a conceptual nutshell:

Here are four numbers, each less than or equal to 100:

20, 15, 5, 8

Here is the product of those four numbers:

12,000

Please convert that exact product to three factors, each less than or equal to 256:

128, 3.75, 25 ?

15, 20, 40 ?

60, 8, 25 ?

...?

Just because the CMYK color gamut is more generally considered a "subset" of the RGB gamut than the other way 'round, doesn't mean there is only one set of values that will "convert" between the two color models. There simply is no precise 1:1 correspondence between the two color models, without an intermediary conversion to and from an absolute color space; which is where color management and device calibration comes in.

So things like color management rules, device calibration, file format--even the angle at which you are viewing different portions of your LCD monitor-- still come into play.

And you do realize, don't you, that you posted your screenshots on a web page. Web pages don't display CMYK images. Your "CMYK" screenshot is an RGB image, being viewed by others on RGB monitors, with who knows what settings and conditions.

JET

2 replies

JETalmage
JETalmageCorrect answer
Inspiring
February 16, 2019

Normally, colours would change if you convert from RGB to CMYK...My problem is that I'm experiencing [color shifs] when I change the colour mode from CMYK to RGB.. this makes no sense to me.

In a conceptual nutshell:

Here are four numbers, each less than or equal to 100:

20, 15, 5, 8

Here is the product of those four numbers:

12,000

Please convert that exact product to three factors, each less than or equal to 256:

128, 3.75, 25 ?

15, 20, 40 ?

60, 8, 25 ?

...?

Just because the CMYK color gamut is more generally considered a "subset" of the RGB gamut than the other way 'round, doesn't mean there is only one set of values that will "convert" between the two color models. There simply is no precise 1:1 correspondence between the two color models, without an intermediary conversion to and from an absolute color space; which is where color management and device calibration comes in.

So things like color management rules, device calibration, file format--even the angle at which you are viewing different portions of your LCD monitor-- still come into play.

And you do realize, don't you, that you posted your screenshots on a web page. Web pages don't display CMYK images. Your "CMYK" screenshot is an RGB image, being viewed by others on RGB monitors, with who knows what settings and conditions.

JET

Monika Gause
Community Expert
Community Expert
February 15, 2019

Please show screenshots.

ldefazAuthor
Participant
February 16, 2019

Sorry, here are a couple of screenshots

Monika Gause
Community Expert
Community Expert
February 16, 2019

That's within a range that can be expected.

Especially with green you have to expect differences.