That’s not Red
01 Find out what you see.
15 plates

Screening

Find out what you see.Pseudoisochromatic screening

A number is hiding in each circle. Type what you see, or say you don't see one. That's a real answer and it counts.Each plate contains a figure rendered in hues separated along a specific confusion axis. Report the digits you perceive, or indicate that no figure is legible.

Type the number and press Enter. If you can't see one, just press Enter with the box empty. That's an answer too.Enter the perceived digits and confirm. Submitting an empty field records no legible figure, which is a scored response rather than a skipped one.

Why this isn't a diagnosisMethodological limitations

This isn't a diagnosis and it can't be. Your screen isn't color-calibrated, mine isn't either, and the brightness slider alone can change your answers. What this is good for is working out which conversation to have next.This screening runs on uncalibrated consumer displays with unknown gamma, white point, and ambient conditions, none of which are controlled. It is not equivalent to a clinical Ishihara examination and cannot be used diagnostically. Treat the result as an indication, not a finding.

These plates are generated from scratch rather than scanned from a book, so they look a little different to the ones you may have seen at the optician. They work the same way.Plates are procedurally generated pseudoisochromatic figures. Dot colors are sampled either side of the relevant confusion line rather than reproduced from the Ishihara series.