The idea of a single universal visual filter to solve colorblindness is a tempting one, but it does not work.
Pushing hues into areas of the spectrum that are more visible (known as daltonising) has its uses, for example using a daltonising app to tell the difference between a green banana and a yellow banana, but color use in games can be too varied and sophisticated for there to be spare frequencies to shift colors into. Instead, all you can do is bunch hues up closer together.
This means that any kind of shifting (including decent daltonising algorithms) changes colors that do not need to be changed, which can result in taking things that could already be perceived perfectly well, and making them harder to distinguish. Pushing hues closer together, replacing some clashes with others, and unnecessarily harming aesthetics. For example changing all greens to blue – changing grass to a hue that no longer looks like grass, when actually all that needed to be changed was the green team name and minimap marker.
To be effective, colorblind support in games should be implemented by game developers rather than at system level, with the first port of call being to reduce color reliance, using additional signifiers (e.g. symbol/shape). If that isn’t possible, falling back to tweaking individual elements that need to be distinct from each other, such as team colors, ideally offering a free choice of color so that all the various edge case medical conditions can be reached. Some good work has been done to reduce the negative impact of filters, but they still provide no possible way of reaching those edge cases, and are consistently stated by colorblind gamers as not being what they want.
There is an argument that something is better than nothing, i.e. if it helps even a minority of colorblind users in a minority of games it’s still worth having.
However as mentioned previously, system level button remapping has caused some problems, with a major publisher thinking that remapping in games was no longer needed because of it being done at system level. If the same was to happen with colorblindness, with good in-game modes being dropped because of a less useful filter having been implemented at system level, the impact on colorblind gamers would be severe, undoing years of progress.
Player feedback on the filter-based colorblind modes in Overwatch
Colorblind support in Destiny, manually designed preset color combinations for important UI elements, while leaving all other visuals intact
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