RGB color profiles
RGB has three primary colors of light: Red, Green, and Blue. Electronic devices like computers and tablets combine these three colors to produce all other colors on a screen.
RGB is an additive color profile because you create new colors by adding primary colors of light together:
Green light + Blue light = Cyan
Blue light + Red light = Magenta
Red light + Green light = Yellow
Red light + Green light + Blue light = White
The RGB color gamut (i.e. the range of colors within a color spectrum) has a broad range of colors because it essentially mirrors how our eyes see color. Our retinas receive red, green and blue light, which is then processed in the brain and allows us to see an array of colors.
Of course, this all depends on one key factor: light. Printed matter doesn't generate light - it reflects it. So how do you reproduce color in print if with no light source? The answer is you need to subtract color, which is where CMYK comes into play.
CMYK color profiles
CMYK stands for Cyan, Magenta, Yellow and Black (the K stands for Key). Unlike RGB, where you create colors by adding two or more together, CMYK is a subtractive color profile, so you remove a primary color of light from any white light that hits it.
White light, like daylight, appears visible to the naked eye, but it's not void of color. White light occurs when all colors in the visible spectrum appear in roughly equal amounts. By altering these amounts, we can subtract wavelengths and produce different colors:
- Cyan ink reflects Green and Blue light - but not Red
- Magenta ink reflects Blue and Red light - but not Green
- Yellow ink reflects Red and Green light - but not Blue
To produce the three primary colors, you have to think in reverse:
- Cyan and Magenta combined only reflects Blue light
- Magenta and Yellow combined only reflects Red light
- Yellow and Cyan combined only reflects Green light
Imagine you have a piece of white paper - it's white because it reflects every wavelength of light. Using Cyan, Magenta and Yellow in different proportions, you subtract specific colors of light to produce a wide range of colors.
You should get Black by combining Cyan, Magenta and Yellow. But our eyes perceive color the RGB way, meaning CMY doesn't produce a perfect result. To combat this, we add black ink. It will absorb all light and provide darker tones and richer blacks.
Converting RGB to CMYK
Since the CMYK profile works on a subtraction theory, its color spectrum is limited compared to RGB. Primary light colors (pure red, green and blue) will often appear less vibrant when converted to CMYK.
In the image opposite, you can see the gamut of available colors with several RGB profiles and those available with CMYK.
Please note that uploading RGB files to our print ordering system will be automatically converted to CMYK values. We believe our conversion system is accurate, but we recommend creating your specific CMYK color for printing.
How to stay in the CMYK gamut
In Photoshop, InDesign or Illustrator, an out-of-gamut warning may pop up in your Color Picker tool. If you see this triangle with an exclamation mark, it will inform you that your chosen color may not print accurately with CMYK.
While the program may suggest a similar color that does appear within the gamut, we have also compiled a list of recommended CMYK color values which should print consistently.
Working with RGB and CMYK profiles
Everything printed on paper will have a CMYK ink color profile. And anything created for on-screen viewing will have an RGB color profile. But you should make and print your designs in CMYK.
However, if you created a webcomic, you would design it in RGB for better web viewing. If you want to print your webcomic, you need to convert your artwork files to CMYK and manually adjust any colors that may not look right. Creating artwork in CMYK for online projects can restrict the creative process due to limited colors.
To get an idea of how your RGB project will appear in CMYK, switch to CMYK Mode in Photoshop or InDesign. Then you can easily see which colors may need adjusting.
If you are using a color profile, use GRACoL2006_Coated1v2 (download it here) - this is our preferred CMYK profile. If color accuracy is vital to your project, you can order one copy to see how your final prints can look. If you have any questions, contact our team of print experts via email, phone, or in the Messages tab of your pending orders - we're always here to help.