Color is a basic concept but it's important to understand it first. Color is weirdly personal because it is the visual perception of the electromagnetic spectrum. This allows a lot of variances from person to person. In design, we work within a few systems to try to limit those variances and this causes a lot of intentionality with color. The Primary systems are RGB (and hexadecimal), CMYK, and PMS (Spot colors).
RGB is the system used for defining colors in digital spaces. Most screens use a combination of Red, Green, and Blue lights to make most colors, so RGB uses that as its basis. Colors are controlled on a scale of 0 to 255 (00 to FF in hexadecimal) with the greater number correlating to greater amounts of the color. Because RGB is based on light, it uses what is known as additive color mixing, which means that the colors will all add together to create white. Hexadecimal uses 2 digits to represent each color (6 total values), and it functions in a base 16 system. This is the best shorthand way to share RGB values and is typically used in user interface design and coding.
CMYK is primarily used for printing, it layers Cyan, Magenta, Yellow, and Black to create colors. This is a Process color, meaning it can have variances. This is subtractive color mixing, which is when you start with white, and the more colors there are the darker it is.
Spot colors are solid colors created using a specific premixed ink, usually based on Pantone Matching System (PMS) colors. Pantone colors are standardized, and each one is assigned an individual number and name, which designers and printers in different locations can use to easily identify the same exact color. Because of this they are based in CMYK but are much more reliable with printing. Since Pantone is a disgusting company, the best system to use is Stewart Semple’s Freetone system. It's a limited copy of Pantone’s system available for free. The one downside is that the colors are not very accessible, but this has been a thing that Pantone has also struggled with but their website was able to fix it.
Kraken Logo Colors:
Squid Squad Colors:
Document Colors for 1410 and 17153:
Data Visualisation Schemes: