Tim Borchmann (grafitti123)

Why do we need perceptually uniform color spaces? Because working with color in code is different than working with color in traditional design tools. Traditional tools encourage designers to think in manual workflows with the color picker as the primary way of choosing color combinations. In this scenario, designers use their eyes to decide whether a color is right or wrong, and the RGB values play no role in this decision. Code is different, because programming languages encourage designers to think about colors as numbers or positions within the chosen color model. This skill is hard to learn if the numbers do not correspond with the output. Perceptually uniform color spaces allow us to align numbers in our code with the visual effect perceived in our viewers. In some cases, perceptually uniformity is essential. A simple example like wanting to choose a random color to be readable against a dark background can be hard in irregular color spaces, because colors wit...

A photograph has a color cast if it contains a color tint that misrepresents the true color of the objects in the original scene. For instance, sunlight can add a blue color cast, incandescent or tungsten light produces a red/orange cast, fluorescent light produces a pink, blue, or green color cast depending on the bulb, old photographs tend to fade to a yellow cast, a projector typically gives a purple cast, some scanners can create a color cast, and photographs produced from film can have a cast from improper chemical development. Both the Color Balance and Levels adjustments are good for removing a color cast or otherwise altering color. Color Balance is preferable for the uncommon situation where the image has a different color cast in the highlights than in the shadows. Such a color shift can happen as a photograph ages. Otherwise, Levels generally gives better results and also allows you to adjust tonality at the same time. In the Color Balance adjustment, the Prese...