RGB versus CMYK is something that we get a lot of emails about so here’s a quick walkthrough to help you understand what’s best for your project and when.
The problem with working in RGB and then converting to CMYK is the difference in colour and tone that this can create – especially with green tones. Take a look at the image above and you’ll see that the RGB seahorse looks bright and shiny, while his CMYK friend is a bit dull and muddy. So how can we make an RGB image look good as CMYK? Two words: Adjustment layers! Once you’ve converted your image from RGB to CMYK, create a new Adjustment layer for Hue/Saturation and bump those tones back up, typically by pushing the Hue towards the greener part of the spectrum and increasing the Saturation. Experiment with your own images to find the result that works for you – Adjustment layers are non-destructive so if you don’t like the effect you can just delete it without affecting your image. Remember to save your original RGB before you experiment with CMYK too!