Hi Elia,

there is no simple solution! In brief, the RGB color modell is 'additive' and is very good for TV screens, for example, where you can add red light and blue light to get bright purple light.
The CMYB color model is 'subtractive'. This is like painting with color pencils.

There are colors that you have in the RGB mode which you can't (!) generate in the CMYB mode!

There are three solutions to your problems:

1) ask your supervisor to do it better ;-)

2) print your images on a printer that uses the RGB modell and than re-scan it with the CMYB modell. This is obviously not the best way, but it works ok.

3) change all colors of your RGB image which are not available in the CMYB mode. How to do this: I did this last year and I have forgotten most of it, but anyway, this is what I recall: In Photoshop:
- create a color wedge that contains all the colors you have in you image (like in a scale bar).
- your image should be in the RGB mode.
- now duplicate it and work on the copy.
- change the mode to CYMB (under the menu item 'image'/'mode'.
- compare the colors, you will see a mismatch - the 'crap'.
- undo the mode change.

- now comes the part I don't recall too well
- you have to evoke 'file'/'color settings'. There you find 'RGB setup' and 'CMYB setup'. You have to change the settings in these panels and than try the RGB -> CMYB conversion again. I think I even build my own conversion file, but I don't remember how I did that.

I'm really sorry, but here you have to invest time.
Good luck, Jens


              PD Dr. Jens Eilers
           Department of Neurobiology
        Duke University, Medical Center
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