Why are Inverted Colors considered an accessibility feature?

  • Why is it that, in most operating systems, the "Inverted Colors" display setting is considered an accessibility feature? Both Windows and OS X include this option so it seems to be a recognized feature and not a vendor-specific quirk.

    I understand that some users are color-blind. This could possibly justify the Black & White, or grey-scale modes for developers wanting to be assured that the experience is cohesive for everyone. What I don't understand is how or why does inverting the display color help someone with any specific, visual impairment or dysfunction.

    As a programmer that wants to understand the need so that I can develop better accessible software, what purpose does this feature serve to the end user who has some form of visual impairment?


    UPDATE

    I asked this question quite a while ago, however, it just dawned on me -- I think I am one of those individuals that this feature was designed for. I almost always try to keep the contrast reversed from the typical settings for my text displays. I hate white backgrounds with dark text! As a coder, all of my textual GUIs are black with green text. This isn't just a throwback to the old monochrome, green screen days. The pairing of the two colors is quite comfortable to my eyes. However, staring at too much black-on-white actually hurts my eyes from some form of eye strain.

    I mention this in an update because the color inversion feature is not useful.. it's annoying! As someone who needs a good feature like this, it's a shame that all implementations that I have ever seen are just a poor attempt at solving a problem. I would hope that Apple, Microsoft and others have done their research but I'm guessing that might not be the case. Color inversion just feels like slapping a band-aid on a bigger problem.

    Developers, if you want to help people who need such a feature as to prevent eye-strain, find ways to change the text and page background and not necessarily the entire display.

    @raybritton, I can see your point (and I wasn't even aware of the UX site-- slipped through my awareness cracks) but I think it could equally apply on Programmers. This knowledge could affect software design and patterns that should be followed for implementation. However, I wouldn't be upset if the general consensus was to move the question.

    Do you have any particular examples of this pattern?

    Since the post was moved I edited out the bit about Programmers.SE. To me (and the programmers mod who moved the post) this makes more sense on UX, since accessibility is more in our domain. It's relevant for programmers to know of course, but IMO whoever *asks*, it should be designers or HCI researchers who *answer*, hence the move.

    Thanks Ben Brocka. I posted this question this morning and I haven't been able to get back to it yet.

    Wow! Thank you all for such good answers and comments. I really didn't think this question was spark such a flurry of thought and information. This is why I like StackExchange.

    I've posted an example that includes an experimental inverted mode that avoids shifting color hues, here: http://graphicdesign.stackexchange.com/questions/926/good-color-palette-usable-for-the-color-blind/67161#67161

  • Ben Brocka

    Ben Brocka Correct answer

    9 years ago

    Research generally suggests light on dark is harder to read in most cases but considering we're talking accessibility, you should know that results for those with normal vision don't necessarily hold true for those with various vision impairments.

    I've heard higher contrast (the mode in Windows is called High Contrast mode I think) can be easier to read for those with impaired vision though; the white text seems to stand out more. I'm curious as to why that is psychologically; the actual contrast ratio should technically be the same between white on black vs black on white.

    Note that it's recommended to increase font sizes and leading when inverting text colors:

    When reversing colour out, eg white text on black, make sure you increase the leading, tracking and decrease your font-weight. This applies to all widths of Measure. White text on a black background is a higher contrast to the opposite, so the letterforms need to be wider apart, lighter in weight and have more space between the lines.

    Mark Boulton

    Also, a common reason for white on black (which this feature mostly produces) is for night reading; many e-readers offer a Night Mode with white on black. The black screen is less painful to read with low to no external light.

    Another reason it might be common is simply because it's easy and relatively safe to to implement. Compare it to other obvious color effect options; if you tried to Sepia tone the whole screen (an effect I've seen to make reading easier on the eyes) you would reduce contrast significantly. Turning things black and white could eliminate color cues used to differentiate interface elements.

    Simply inverting colors preserves the relative contrast between UI elements (so you won't have black text on grey backgrounds), so it's a "safe" effect at the least. And if it doesn't help, no harm done, just undo the effect.

    I've been inspired to ask a related question on cogsci.se

    While this research is interesting, it actually reminds me of the New Coke debacle in that people preferred New Coke _in small doses_, and Coke mistook that for preferred _period_. Black on white might be easier to read in a sample, but it can strain the eyes over a longer term (on computer screen at least).

    Mark Boulton: "White text on a black background is a higher contrast to the opposite". Since contrast expresses the amount of difference (which can be measured accurately), how can white differ more from dark then dark from white? Unless we're discussing two types of 'dark'...

    @IgorAsselbergs I suspect the problem is not quite as black and white as you are making out, and that it's more to do with the sensitivity of the eye to white when the surrounding area is dark - allowing they eye to be more rested and therefore able to pick out the brightness; as opposed to being 'saturated' (strained) by a harsh white background and picking out less exposed areas. Much like the ability to pick out stars in the night sky. In other words it's not down to a contrast calculated purely on RGB values, but more down to the way the eye works. Perceived contrast vs physical contrast.

    You also need to think about the phsyics of the medium. A computer screen is emitting light. Light text on a dark background is perceived to have stronger contrast because, actually, it does, because the glow doesn't run "in" from outside the letterforms, but out of them. Also the screen is not, compared to paper or E-Ink, a constant image, but a "flickering" one (even at nowadays high rates). This tires the eyes. Less white = less flickering = less strain on the eyes.

    I'm one of those vision-challenged people, and @RogerAttrill and Christian are spot-on WRT my experience. The bombardment from a background full of light-emitting white pixels makes the black text harder to read, particularly with extended usage. But I can read for hours on my Kindle (e-ink) with no problems; paper (real or simulated) is different. BTW, the Mac "solution" to this problem is completely useless to me; pixel inversion does too much collateral damage (like photos). On Windows I can define a color scheme. (I use my Mac for shorter periods of time; work machine is Windows.)

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Content dated before 7/24/2021 11:53 AM