Color
Images and color: cameras deal with the colors of light, which are RGB (red, green and blue). If you were to take three flashlights with red, green and blue lenses and overlap them, you would create several other colors. CMYK deals with pigments, or ink. When crossed, pigments behave differently than the colored flashlight lenses. It takes four colors to make as many color combinations. Because CMYK is a representation trying to mimic the colors of light, it will never be quite the same as viewing your image on a computer screen (also RGB) or as when you were actually there taking the picture. Nevertheless, we are stuck with CMYK for most prints, and in order to keep your expectations from growing wild about color, please convert your images that go into documents and publications, posters, etc. to CMYK. To the trained eye, they will appear a little less brilliant but the color space conversion is more important.

For the same reasons as explained above, color for print will be more accurate if you start the document as CMYK. Printers use percentages of Cyan, Magenta, Yellow and K (black) pigments or dies. If you have ever had a case where you’ve tried to make a color 100% black and as soon as you save the document it changes to a different percentage of black, you may want to check how the document is set up. When this problem occurs, it is usually because the document is RGB and is overriding your attempts to use CMYK color swatches.
Check if your document is CMYK:
From Indesign click on File, Document Setup. Make sure that Print is selected from the Intent dropdown menu. Use only CMYK swatches and images and you’ll be fine.
From Illustrator click on File, Document Color Mode, and ensure that CMYK is checked. Use only CMYK swatches and images and you’ll be fine.
From Photoshop click on Image, Mode and make sure CMYK is checked. If it is not checked (RGB is default), go ahead and click on it. Photoshop may ask you if you want to flatten the layers because changing color modes will likely have unexpected results in some kinds of layers. Personally, I would save a copy of my file and flatten that one.
If you use Microsoft Publisher go here to get a great comprehensive tutorial: http://www.bestprintingonline.com/mspublisher.htm
For Quark Express see this: https://www.edwardsbrothersmalloy.com/blog/creating-print-quality-pdf-documents-quark-express-8-0/
Microsoft Word doesn’t retain CMYK values reliably. If it is the only tool you have available and you’re on a budget, just be advised that in some cases you printer (that’s us, not your desktop printer) may convert the file to CMYK but the conversion could produce results that you did not intend. For example, when we use Adobe Preflight to convert files for digital printing, an occasional red tone will insert itself into the images. Red faces are no fun! Additionally, if you get a digitally printed proof using RGB images, but the job will be printed on the offset press, the color will be very different.
About the Color Black
Black is great. It’s sophisticated and professional. Getting the best black prints require some finesse and it depends largely on what your document contains. There are two kinds of black: %100 Black (C0, M0, Y0, K100) and Rich Black (a combination of CMYK to make black). 100% black can be a bit dull in large surface areas (unless you are printing on a laser printer), and Rich Black can be, well, rich! It is velvety, or can have a slight hue of any color you like.
This is why it’s important to communicate to designers how many colors are needed and likewise, designers need to tell clients how many colors are used. Cyan, Magenta, Yellow and K (black) are all colors and if you use a rich black, you will likely be charged to use all four of those colors.
In projects with color images (you’re using all four anyway) it’s recommended to use rich black in large areas with no text to get a deep black color. Our favorite Rich Black build is C40,M30,Y20,K100.
For text, whether it’s black or reversed out of a black background, we recommend %100 Black (C0, M0, Y0, K100). If you use Rich Black ,the text will be a little fuzzy from lining up all four layers on top of eachother.

Watch out for images that look black but are really a build of all four colors. If you are making a document that prints only in black, be sure to convert that image to greyscale.