GRAPHIC DESIGN
LEVEL ONE
CMYK vs. RGB
Speaking about color, did you ever notice that the colors on your computer screen or on your phone seem like they are so much more vivid and bright than the colors in your textbook and magazines? Did you ever wonder why it is that "they" can't print things like you see them on your screen? Prepare to learn the actual reasons why!
What is CMYK?
CMYK stands for Cyan, Magenta, Yellow and blacK. These are the colors we will use in this class more than others. These colors are used in printing. Its kind of a nifty process. Below is a picture of a butterfly. It shows what are called color separations. Essentially each color gets a "screen" and that screen gets printed. As it gets printed, a new screen is layered over the top until the final result is a full-color photo.
Here's a little more science...
Printing presses use color inks that act as filters and subtract portions of the white light striking the image on paper to produce other colors. Printing inks are transparent, which allows light to pass through to and reflect off of the paper base. It is the paper that reflects any unabsorbed light back to the viewer. The offset printing process uses cyan, magenta and yellow (CMY) process color inks and a fourth ink, black. The black printing ink is designated K to avoid confusion with B for blue. Overprinting one transparent printing ink with another produces the subtractive secondary colors, red, green, blue.
The illustrations to the left show process inks printed on white paper. Each process printing ink (cyan, magenta, yellow) absorbs or subtracts certain portions of white light and reflects other portions back to the viewer. Process printing inks are transparent. It is the paper that reflects unabsorbed light back to the viewer.
So as you can see, it takes different amounts of each color to make the picture show up the right color in the end. There is a lot of yellow, quite a bit of magenta, some cyan and a little black but when they combine - BLAM - full color.
This CYMK process is called subtractive color. Subtractive color is what you get when light is refracted off of an object before it bounces to your eye. It is called subtractive because if you mix cyan, magenta & yellow equally and subtract the light, you are left with black.
Printed materials are among the places that you find the CMYK process being used. Other things that use subtractive color are plastics and fabrics.
What is RGB?
RGB stands for Red, Blue and Green refers to a system for representing the colors to be used on a computer display. Red, green, and blue can be combined in various proportions to obtain any color in the visible spectrum. Levels of R, G, and B can each range from 0 to 100 percent of full intensity. Each level is represented by the range of decimal numbers from 0 to 255 (256 levels for each color). The total number of available colors is 256 x 256 x 256, or 16,777,216 possible colors.
In the Hypertext Markup Language (HTML), the color for a page background or text font is specified by an RGB value, expressed with six digits in hexadecimal format. The first and second digits represent the red level; the third and fourth digits represent the green level; the fifth and sixth digits represent the blue level. In order to actually display the colors for all possible values, the computer display system must have 24 bits to describe the color in each pixel. In display systems or modes that have fewer bits for displaying colors, an approximation of the specified color will be displayed.
So we call RGB additive color because light is added and it makes the colors appear more vivid.
Where do we find RGB color?
On your computer screen, iPad, smart phone, television, electronic billboard... anything that uses light behind it for illumination is where you will find RGB or additive color, being used.
Why do pictures on the internet always look more vivid
than when I print them out on my color printer?
Oooh that's an excellent question and I'm glad you asked! It has to do with a few things, so the answer isn't a simple one but the question is awesome!
Computer monitors have a larger color gamut than printing, which is why a computer can display a million more colors than what can be achieved with printing. Printing deals with absorption and reflection of wavelengths of which we perceive as color (CMYK). Printing also has its own limited color gamut. A lot of times people will note that something looked different on screen than it does on paper and it is because of the different color ranges that computer monitors and printing allows.
So how do I know which one to use? RGB or CMYK?
When it comes to deciding to use RGB vs CMYK, first figure out what the output will be. If the output will be on a computer monitor then RGB is the way to go. If the piece will be printed, CMYK is usually the standard and the best option. Thats all there is to it when it comes to using RGB vs CMYK colors on your projects.
So your main projects you do on the computer should most typically be done in CMYK however when you save the JPG for your website, you will need to save it as RGB in order for the image to show up correctly. Naturally I will show you how to do this when the time comes.
