I was brought up knowing I was Red/Green colourblind. But there are actually quite a few types of colourblindness.

So what type am I? Well, I can see colour. So I'm not monochromous (no colour receptors). I can clearly tell the differences between all forms of primary and secondary colours, and none of them even nearly look black, so I am not dichromous (missing one of the three colour receptors).

Oh, and as an aside, the three colour receptors in the eye are not red, yellow and blue. They aren't even red, green and blue. They are more accurately short, medium and long wavelengths, which in the eye correspond to peak sensitivity at blue, yellowish-green, and yellow (respectively).

So, I am some subcategory of anomalous trichromacy. I have some weakness in some of my colour receptors. When they list usual red/green types of colourblindness they most often say...

• Tritanomaly, blue receptor is weak, very rare
• Protanomaly, the yellow (also responsible for red) receptors are weak. About 1% of males
• Deuteranomaly, the green receptors are weak, by far the most common, about 5% of males

Given how much more common green weakness was, I presumed I was deuteranomalous, but no longer! For I have recently discovered I am, actually, protanomalous. As well described by the following paragraphs and images.

the redness component that a normal observer sees in a violet or lavender color is so weakened for the protanomalous observer that he may fail to detect it, and therefore sees only the blue component. Hence, to him the color that normals call "violet" may look only like another shade of blue.

Under poor viewing conditions, such as when driving in dazzling sunlight or in rainy or foggy weather, it is easily possible for protanomalous individuals to mistake a blinking red traffic light from a blinking yellow or amber one, or to fail to distinguish a green traffic light from the various "white" lights in store fronts, signs, and street lights that line our streets.

You learn something every day. And I think they most shocking thing I learnt is that one of the side affects of my type of colourblindness is that a large part of my inability to see colour is due to the colours' perceived lack of 'brightness' (an affliction not found in the more common 'green weak' type). Or, as wikipedia puts it

They may learn to distinguish reds from yellows and from greens primarily on the basis of their apparent brightness or lightness, not on any perceptible hue difference. Violet, lavender, and purple are indistinguishable from various shades of blue because their reddish components are so dimmed as to be invisible

So let us take a few moments to mourn the loss of our friend, the red.

Are you colourblind? Which type are you?

p.s. Yes, I can see pure red (although most likely dimmer). My red receptors are weak, not missing.