A psychophysics study, and a tool built on it

Which lens tint separates a clay from its background, for your eyes, on your field?

A tinted lens cannot add light. It can only remove light differently from the clay and from what is behind it, and whether that helps depends on the clay's pigment, the background, where the sun is, and how sensitive your eyes are to the brightness and colour differences that result. All four are computable or measurable. This site does both.

Take part in the study

About 25 minutes on a laptop with a keyboard and a bank card. It measures your sensitivity to luminance, red–green and blue–yellow contrast, then tests whether a model can predict which lens classes work for you. You get your profile at the end.

Needs an account from the study team, or a registration code.

Lens recommender

Describe the scene (clay colour, background, sun position or the place and time you shoot) and get the predicted clay–background contrast through each lens class, ranked, with the assumptions shown and an honest "no tint helps here" when that is the answer.

Predictions from a physical model. Not yet validated in the field; see the method page.

Method and references

How the contrast is computed, what the display can and cannot reproduce, where the lens and clay spectra come from and how sure we are of each, and the studies the design rests on.

What this is not. The colour-vision task is a screening measurement on an uncalibrated display, not a clinical test. The lens ranking is a model's prediction; no field benefit has yet been demonstrated, and no claim of improved scores is made. Lens spectra are labelled by provenance: measured, traced from a maker's chart, or an assumed shape at the maker's stated transmittance.

Part of Clay & Cortex. Built on the same calibration and adaptive-threshold instrument as the trap occlusion study.