Text-only cheat sheet:
Print. CMYK Stands for Cyan, Magenta, Yellow and Key (black) the four inks used in most printing processes. Digital work that will be printed should be set up in CMYK.
Fancy print. Spot Color is used when exact color matching is crucial or when printing with specialty inks like metallic or neon inks. Using spot colors is a lot like buying paint at home depot—you chose a color swatch and hand it to the mix master at the counter who then uses that swatch’s recipe to mix your paint. To pick your spot color swatch, you need a Pantone Guide Booklet that shows you the swatch's corresponding PMS code to give to your printer Example: PANTONE 115C is a bright yellow.
Digital. The colors Red, Green and Blue are combined with the backlight of the computer monitor to produce specific colors. Without the light of the display, RGB colors render differently which is why printing an RGB image produces different results than printing a CMYK image.
Web. When designating colors in HTML and CSS, we use hexadecimal codes. Similar to RGB, Hex codes combine red green and blue values to produce specific colors: #RRGGBB