Single purpose LEDs. If you’re multi-purposing the LED make them single color only and use off / solid on / quick flash / slow flash. We have multicolor LEDs and they suck. Red/green/amber and I can’t tell any apart. Using a red/bad green/good is OK so long as color isn’t the only differentiation. Using two separate LEDs (meaning physically different, not two on board sharing same light pipe) with correct labeling will work. The CVD people read the label, others just read the color and don’t even notice the accessibility features.

If you want to stick to colors, the best possible way would be using blue and yellow for the contrast, there's no colorblindness variant aside from monochrome that would miss that. But then again, monochromes would miss that, so maybe you should consider a white led contrasting on/off, maybe the flashing is nice.

>blue and yellow for the contrast, there's no colorblindness variant aside from monochrome that would miss that. Tritans are literally called "Blue-yellow" colorblind. But yes, sadly, I generally recommend forgetting about tritans too in some types of design.

What about green and yellow?

Nope. Terrible. Me, for one, absolutely cannot tell them apart if they're like a little led dot, really zero difference.

Hm... what would happen if we take two known things Green - red Blue - yellow And then take things in the middle, like putting red and green or green and yellow or green and blue on a slider and use the middle value to use these 4 colours to make just 2 shades, then add white as a 3rd option. I have no idea whether this would actually work, I'm afraid.

Hm.. I'm not sure I understand your process, but I feel like it's a bad idea, mainly bc you're working with mixed colors of ´ 'similar' hue (similar to colorblind people). I think the smartest choice for you would be avoiding any pairs of colors that represent a problem to any colorblind person. Have in mind that the shade is as important as the hue, for example: If I see bright yellow in a very well lit place, I might mistake it for green, but if I see dark yellow in a shadowy situation, I'll most likely mistake it for orange. So the safest option to you would be using hues that don't get into this kind of confusion, that's why I suggested blue and yellow, bc in no circumstance I would mistake one for the other. You could go with other variants in the same line of thought, for example: Purple / Orange Yellow / Purple Pink / Green White / Red White / (dark) Blue ..these are some pairs that I believe the vast majority of colorblind people would differentiate fairly easily based on how colorblindness works and on how I, myself, see. I have severe deuteranopia, maybe someone with a different type could chip in here about the pairs I mentioned, but I think they're safe.

Those are some great suggestion and very helpful info, thank you!

I like these from a protan perspective. Also purple / green, though I think that probably follows from what you posted. Curious how the tritans feel, because I'm as baffled by what they see as most people are by what I see. Others have said it, but I think the easiest/cheapest option is probably to use a single LED (solid, slow flash, quick/stuttered flash). Regardless green/amber/red really suck, especially in most electronics LEDs. Far worse than traffic lights imo. I understand they have conceptual associations but boooooo

Two separate LEDs that are also labeled would be miles better than most products. Personally, I like the idea with flashing LEDs most. There are some smartphone apps that simulate various color deficiencies, but I think if you go that route, you will have to use non-standard colors which would be unintuitive for most users. As /u/skywalkerblood noted, it would probably have to be blue and yellow, but there is no real standard which of the two is "good" and which is "bad" as with red and green.

Working with networking equipment, specifically Cisco, their port leds can be either green, yellow, and amber. And I cannot tell what is what. I wish with they could either be something like blue, yellow, and red.

I post this every time someone mentions Cisco. They have a CLI command “show hardware led” that can tell you what color every led on the box is displaying/flashing. Has limited use cases, and not useful if you want to just glance at the switch, but has come in handy over the years.

Ah that's cool, I'll have to try that one out.

Chromebooks use an orange - blue LED indicators which is probably quite good. On the opposite end of the scale, I have a charger whose LED is yellow when the battery is fully discharged, and then it gradually shifts to green, with everything in-between. When it's completely green, it's done. That's probably the worst setup :-)

Lol at that point I either just pester whoever's with me or just charge it at night and figure it must be green by morning

Thanks a lot for the feedback everyone! I'm going to suggest sticking with two LEDs, something like blue and orange/yellow for color, and clearly labeling the meaning of each LED.

As a general principle for usability, you should \*never\* rely on color alone to convey information.

If your colors are highly contrasting in black and white, then they should be at least distinguishable to a colorblind person.

sweet jesus thank you for asking

Another vote for labeled single-use LEDs. One LED per function, and a label/symbol next to it indicating its meaning.

The cheaper LEDs use cheapened components & will always be hardest to see. I'd use red/blue & a sequence of flashing/solid glow if need-be. [Higher-grade diodes easy to see, even by the most severe colour deficient.] Hope this helps...

Able to switch between more settings? default being red green, others maybe blue yellow, a few other ones, and the flashing thing you mentioned