Need to find a Color Resource - HELP?

For an app I am doing I need 5 colors… or perhaps 5 pairs of colors.
These are to code values that are low, high, normal, borderline etc.

I need a RED, ORANGE, YELLOW, GREEN and BLUE values
the look good (and can be read) on a WHITE and BLACK background.
The values for White vs Black backgrounds do not have to be the same, just readable

Most of what I have come up with looks fine on a black background, but like yellow is hard to read on a white background

Basically this is the Xojo Color … whatever they named it … project item
Which is what I would create for yourself IF you dont already have it
Or something like that
Then in just create a pile of them and refer to them globally (which is pretty much what I expect Xojo does so you can refer to them by name)

Finding the right colors I’ve used

there’s another one but I’ll be damned if I can recall the name
try searching google for “high contrast color finder” or something like that

this one you can put in original colors and some criteria and it will then test a pile of option and give you back results that meet those criteria based on your original inputs

that said yellow on white is probably never going to give you ver decent contrast regardless of what you do

Make the YELLOW a little bit more red-ish, until you find it readable. Then adjust the ORANGE so that it’s “equal distance” from the YELLOW and the RED. The RGB values 255/225/0 for YELLOW are quite readable on a white background in my opinion…

And you could make the white background a litte gray-ish, too.

well 0xffe000 is not readable to me :(… but I’m going to try the right column of this and see how that works

Well, perception of color does differ from person to person. So the values I’ve given to you were meant as a starting point. On the other hand you will quite quickly reach a point where the color “suddenly” turns into orange.

As Norman already said, yellow on white is always problematic, contrast wise.

Would a gray color work in the middle?
Use a drop shadow on white background?
Does the white have to be white?

The tool I have used, and maybe the one Norm is referencing, is Colour Contrast Analyzer (free). I keep two versions around with the latest having a new UI and is Electron based IIRC. I believe if you grab 2.2 or maybe 2.3 from their archives though, you get a full on Cocoa app and IMHO a better UI.