Color coding doesn't decrease usability for disabled people (and I say that as a screen reader user). You just need to ensure that color is not the only way the relevant information is conveyed.

Certain types of colorblindness combined with certain colors makes text much harder to read than black-on-white. If you limit yourself to just universally readable colors, you're heavily limiting the number of different categories you can highlight. There's also the matter of screen real estate - duplicating info isn't helpful for people who can deal with colors just fine. I'm not saying it's a srong thing to do, just pointing out accessibility and usability are different things.

Couldn't you distinguish things by their grayscale value? Then you change the hue on top of that for people who can see color.

May not always be enough contrast to pass WCAG requirements, for example.

Colors should be an OS feature. On iOS and macOS you can remap colors globally and it works in all native apps. There are presets fire the common cases: red/green issues, color blindness etc and you can make your own. This has its limitations though eg if you are not able to distinguish at least 5 or so colors… any colors.

That's why you don't just use colour for identification. E.g. include a warning icon next to a button/element in addition to using a warning colour.

Nor just shape, so a warning icon + text message.

and, as is being increasingly forgotten, SOUND QUES. Seriously, I get they can be annoying but they make navigating and interacting with things so much easier if you can't see them. Sure, TTS exists but is far more inefficient and objectively less helpful in these kinds of circumstances

*cues

Another great example of increasing accessibility while reducing usability.

should be, but then you will upset all the marketing folks and their brandings.

But you can — or should be able to — independently toggle all of those features. For example, the app should work in high-contrast mode with disabled color coding, it should work with touch gestures disabled, etc.

A good common framework helps here. Then, it's up to each user to set their settings properly.

Riddle me this - why would you want to disable something that increases usability of an application? (Yes, this is a loaded question - I never said these features are bad, just that usability and accessibility are sometimes at odds with each other.)

There are very few accessibility features that increase usability across the board for everyone.

If they did, they'd just be called "features".

Disabling high-contrast display makes the colors more aesthetically pleasing.

Disabling large-print text allows you to view more text on the screen at one time.

My point exactly. Accessibility isn't "just usability" and the great-great-grandparent was wrong to say that.

unsure this is quite the same thing, but I often swap my phone to gray scale to reduce brightness overall (and 'reduce whitepoint' sometimes) because at night colors are too stimulating.

> Riddle me this - why would you want to disable something that increases usability of an application?

Why don't you run your apps/OS with every usability feature enabled? Share your reasons.

I think you are mistaken which side I am on in the "accessibility is just usability" debate. For the record, I am on the side that says not at all.

Nope! But that you can't answer my question says all I need to know about the type of person you are.

Sometimes users may prefer to reduce the degree of accessibility of an application in favor of aesthetics.

I have my opinion on aesthetics of additional ways of repeating information already available by color coding. But to each their own.

Other than that, is enabling/disabling any of the aforementioned features ever a question of aesthetics?

For example, opting to not enable high-contrast mode is a question of aesthetics. Arguably reading text would become easier for the user, but they prefer to sacrifice a little of the readability in favor of looks.

In fact, for some people high contrast is headache-inducing.

I’ve installed a utility on my laptop that supports “sub-zero” display dimming for nighttime use because monitors are now over-optimized for max brightness, with min brightness being retina-searing for eyes adjusted to a dim room.

I am a little confused about your response. Do you disagree with me that accessibility features often reduce usability, or do you agree with me and just feel like nitpicking? I'm all for nitpicking, but I'd rather keep it separate from the real debate.

> Another is using smaller font size to make more info visible at once

This doesn't sound very usable to me.

You might be the kind of person who does benefit from accessibility features such as larger font size. On the other hand, I'm not; I can read 10pt font on 100 DPI display just fine, without glasses. I'd rather have an extra column in table view visible without scrolling than larger letters, but for you the tradeoff might be different. That's why it's accessibility and not usability. Usability would be if the bigger font didn't push anything off screen, then of course it's better to make it bigger.

Yes and unfortunately font size is usually one of those things where everyone is subjected to the "improvement". Accessibility guidelines should not be specifying minimum font sizes but rather require websites to respect the browser settings.

Everybody has some minimum text size they're comfortable with. If you make the text bigger than that, they're forced to scroll unnecessarily, which is less usable. But the size differs from person to person, so it should be configurable. You get this automatically with web browsers and most GUI frameworks if you don't go out of your way to break it (just stick with the default font).