I've been trying different pencils, crayons, acrylic and watercolor paint, oil pastels, but I haven't been able to find anything that I can take picture of, and invert/negate digitally to make a bright red color.
At best I am able to get orange with "sky blue" ish colors, and magentas with some teals but nothing seems to produce a primary red(hue 0 in hsv, preferably with 75+ saturation, 75+ brightness).
Here is a picture of my screen with a cyan rectangle on it, which succeeds inverting to red, although a bit dark. In the process of taking the picture, it shifted to hue 173, saturation 54, brightness 100 from the original hue 180, saturation 100, brightness 100. but this is largely if not completely due to a bad camera, the computer screen cyan seems like the brightest cyan I've ever seen other than perhaps cuba ocean, and I might be misremembering about that(it might just be bright aqua).
Here's a cropped google result similar to what I remember of cuba, but even so it has no perfect red at all indicating absence of very bright true cyan, but again it might be because of image capturing process, and there still might be some grayer cyans that I haven't been able to filter out.
Is there any reason why sky blue(eg hue 191, 80, 100) is the closest I can get to true cyan using non direct light emitting media?
I am just a bit confused since cyan blue is incredibly easy to invert into since yellow is quite abundant, and green is incredibly easy to invert into since red-violets are quite abundant, but red seems really tricky, even after buying sets of 100 pencils, 96 crayons, various paint sets, none of them have any colors that invert into red, at best, only teal and sky blue come close but don't invert to red.
Sidenote, I have managed to find that a few teals could invert into hue 2, saturation 74, brightness 68, which is really close, but is too dark of a color to work as a subtractive primary.
I imagine there must be butterflies that can force this wavelength to be reflected with nanostructures.
Is there no pigment that blocks only red wavelength, why is true cyan so rare or nonexistent?
What's stranger is that inverted space has plenty of bright cyans yellows and magentas, and non inverted space has plenty of reds, greens, and blues, but inverted space reds are really rare, and regular space cyans are really rare.