I'm a total, utter, complete loss here. Basically we're making a photo filters app for iOS

I have created several filters in Photoshop and every one of them uses color balance. The programming library we're using requires color balance to be adjusted using RGB and NOT CMY

I tried converting the CMY values from photoshop to RGB but it always gives wrong color in RGB. Tried and tested various online CMY to RGB conversion tools.

here's a screen shot. I think perhaps K is missing here in photoshop

where in the world did K go to?

So, can somebody please explain how do I convert this CMY system to RGB? Also, the CMY values here are between -100 to 100!

WHY oh WHY!? I'm pulling my hair out not a single CMY to RGB conversion tools takes negative values! :'(

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  • Your iterpretation is wrong reducing red means image gets more cyan as the remaining colors form cyan – joojaa Jun 3 '15 at 15:41

Oh my... No, you are getting this wrong.

You do not need to convert from CMY to RGB. All the colors share the same space.

If you remove lets say the Cyan you will get this:

Simply. If you add more Red (R+) you will get a redish image. If you remove red (R-) you get a cyanish image. The Cyan is the complementary color.

But I agree that the UX of your example is wrong.

If you are puting a marker Cyan it also should have a numeric value (A)

But if you only want it to be a Red slider it should be an absolute Red value (B)

It has nothing to do with converting the 2 color modes.

  • The dialog has CMYRGB, so I tend to agree that the OP's interpretation of the context is wrong. The sliders are sort of a seesaw as is appropriate for use with balance – Yorik Sep 1 '15 at 15:33

You are at the wrong place. Color balance is not for converting from RGB to CMYK. -100 to 100 are not the "K-Values" which are from 0 to 255.

Try instead: Edit > Convert to Profile. Then select the CMYK profile of choice.

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