Who made thisAuthorship

One colorblind person, a laptop, nothing for saleProvenance, scope and conflicts of interest

I'm Zack. I have red-green colorblindness, which is the whole reason this exists. I got tired of explaining that no, it isn't black and white, and no, I can't just look harder. It turned out to be easier to build the thing than to keep describing it.The author has red-green colour vision deficiency. This site was built to demonstrate the perceptual effect directly rather than describe it, on the grounds that a simulation communicates the deficit faster than prose.

What this site will not doDeclared limitations

It will not diagnose you. It cannot: your screen is not colour-calibrated and neither is mine, and a screener on unknown hardware is a hint, not a result. It will not tell you what a colorblind person sees, because nobody can. And it will not sell you glasses.No diagnostic claim is made. Screening runs on uncalibrated consumer displays with unknown gamma, white point and ambient conditions. Simulations model discrimination loss, not subjective appearance, which is not recoverable from another observer. No commercial relationship exists with any vendor.

How it is paid forFunding

It is not. There are no ads, no affiliate links, no email list and no account to make. Nothing you type or upload leaves your browser. It costs me a domain renewal once a year and that is the entire business model.No advertising, affiliate arrangements, data collection or user accounts. Image processing is performed client-side; uploaded images are never transmitted. Operating cost is limited to domain registration.

Where the numbers come fromSources

Prevalence figures come from the National Eye Institute, the American Academy of Ophthalmology, MedlinePlus and Colour Blind Awareness. The simulation itself comes from a 2009 paper, and how it is implemented is written up in full.Epidemiological figures are drawn from the National Eye Institute, the American Academy of Ophthalmology, MedlinePlus and Colour Blind Awareness. The transform derives from Machado, Oliveira and Fernandes (2009).

Read how the simulation worksImplementation notes

CorrectionsCorrections

If something here is wrong, I would rather know. That goes double for the clinical detail: I am colorblind, which makes me a witness, not an ophthalmologist.Corrections are welcome, particularly on clinical detail. The author writes from lived experience and published sources, and holds no clinical qualification.