RGB Definition and Meaning

According to AbbreviationFinder, RGB stands for Red-Green-Blue.

Differences between RGB and CMYK colors when working with Photoshop

When starting to work on a project with Photoshop, it is essential to decide which mode or type of color to use. RGB and CMYK modes can be indifferent to the naked eye, but choosing one or the other can help or create problems. What are the differences between them according to their use and color theory?

RGB, colors by adding light

The RGB color model is an acronym for the three basic colors that make it up: red, green and blue or what is the same, in English, red, green and blue. This model uses the mixture of these three basic colors to create a pixel of a certain color.

Each of the three colors has an intensity ranging from zero to 255, thus creating 256 different shades for that color. The combination of these three variants offers a palette of more than 16 million colors.

When dealing with light colors, the sum of the three to the maximum of their hue will result in the color white, while the sum of the three colors at their zero value will create the color black.

Using an RGB color mode

In graphic design, work will be done in RGB mode as long as the final result of the work is intended for a screen support. This means that this mode will be chosen if you are working for the web, for an online presentation or for video. GIF and JPG files will be the most used when working in this mode.

If you look at a screen with a magnifying glass, you can distinguish the pixels that make it up, and in each of them a subdivision with the three basic colors of RGB: red, green and blue.

CMYK colors, by adding ink

CMYK colors are those that are created from the sum of four inks of different colors: cyan, magenta, yellow, and black. In English, the acronyms come from cyan, magenta, yellow and black.

Unlike in CMYK mode, these values ​​will be darker the higher their percentage. In addition, these colors have, in Photoshop, a range that goes from zero to one hundred (instead of the 256 levels of RGB).

In pure theory, it would be enough to add cyan, magenta and yellow to obtain the color black, but the reality of the printing shows that the mixture of these three colors to the maximum of their tonality gives a dark brown color. For this reason, to work in graphic design, a fourth color is added, black.

Using CMYK color mode

The CMYK color mode is used whenever your work is designed for print output. It should be noted that the result of a printed job will never be the same, in terms of colors, as what the user sees on the screen. However, working in CMYK mode there will be fewer surprises when the design is printed.

Change color mode in Photoshop

The color mode of a Photoshop file can be changed from the ‘image> mode’ menu.

Sometimes it will happen that you start working in RGB mode and then change the color mode to CMYK. This change usually involves an alteration in the colors of the design, which becomes duller when it is switched to ink colors. The difference will be more appreciated in the areas with more vivid, more luminous colors, and will be especially accentuated if they belong to the range of green or blue.


It is interesting to note that the conversions mentioned here are of the nominal type. They will produce an irreversible conversion between RGB and a subset of CMYK; that is, you can choose a color from the RGB palette and convert it to certain CMYK colors, and from these CMYK colors obtain the original RGB equivalents that correspond to them. However, converting from CMYK to RGB colors is generally not reversible; that is, a color given in CMYK and converted to RGB will not result in the original CMYK color when it is reconverted back to the CMYK palette.

In addition, CMYK colors can be printed in very different tones than they are seen on a monitor. There is no “good” conversion rule between RGB and CMYK, because neither model represents an absolute color space.

Converting between RGB and CMYK

To convert between RGB and CMYK, an intermediate CMY value is used. The color values ​​are represented as a vector, each of which can vary between 0.0 (non-existent color) and 1.0 (fully saturated color).

CMYK to RGB conversion

To achieve the conversion, you first go from CMYK to CMY, and then to RGB.