There are many articles on the web that talk about using RGB instead of CMYK for your images. RGB gives you a greater color gamut and your images will look brighter and more colorful, and that is correct. If you are working across multiple media (print, social media, etc.) you will want to keep an RGB version. However, if the image is going to be printed, before you spend lots of time working with the color in your image you should talk to your printer.
The idea that keeping your images in RGB will get you better results when you print your images is based on using profiles. These profiles alter the color of the image in a favorable way when the file is processed for printing. But if your printer does not utilize color profiles, they will be tossed out and the image will be converted to CMYK and all of you color work will be for nothing.
Most printers have a color management system in place to control the color across all of their devices, so that color is consistent and predictable. That means they will not use external profiles that might be included in a document or file because it will alter the profiles they have set up. So all profiles are discarded.
If you supply open files or PDF files to your printer, the results will be the same. All profiles will be stripped out and everything will be converted to CMYK based on the printer’s settings.
If you want to make sure you have great color, work with your printer. You can ask for color proofs off their system which will show how the elements and images will look once they have been run through the printers profiling system. These proofs are calibrated to the printers presses and will show very accurately how the piece will look on press. You also need to consider the paper you will be printing on.
Paper can affect the color of you printed piece depending on how bright or dull a white it is. Is the paper coated or uncoated, gloss or matte? All of this needs to be taken into account when you consider color. Printing Partners is more than happy to work with you to create proofs and offer any suggestions to help make your piece look fantastic.