How additive color works
Screens emit light rather than reflecting it, so colors are built upward from darkness. Red and green light together read as yellow, green and blue make cyan, and all three at full strength make white.
Each pixel carries three values, typically 0 to 255, describing how brightly each channel shines. Black is 0, 0, 0 and white is 255, 255, 255 in the usual 8-bit scale.
Reading RGB values and hex codes
Design tools write these triplets as decimal numbers or as hex strings. The color 255, 0, 0 becomes FF0000, which is the shorthand web designers use in stylesheets.
Because values map directly to display channels, what you see depends on the screen's calibration. Two monitors can render the same RGB numbers with a slightly different appearance.
- Red, green, and blue channels combine to form color
- Full intensity of all three produces white
- Hex codes are just compact notation for the same values
- Web images are stored and displayed in RGB
RGB in images and conversion
JPEG, PNG, and WebP all store pixels in RGB, so images look correct on any screen or browser without translation. That is one reason RGB dominates digital photography and the web.
Print does not work the same way, and moving from RGB to ink-based color requires a conversion step, which is where CMYK comes in. Until that conversion happens, images displayed in browsers, editors, and photo apps all stay in RGB from capture to screen.