Which patterns to display
colorcal reads three charts. They live on testpattern.app, a sibling site in the same suite, under the pattern family called Color calibration. They are free, they generate in your browser, and you can download them at whatever resolution your wall runs at.
At a glance
Six frames, three charts
| Chart | Pattern id | What it measures | Frames |
|---|---|---|---|
| Neutral hex chart | neutral-hex |
Color. Where the wall's neutral sits, and how far off each hue direction is. | 4 (Value 25%, 50%, 75%, 100%) |
| Grayscale wedge | grayscale-wedge |
Tone response. How brightness climbs from black to white in 11 steps. | 1 |
| Black field | solid-fill, color Black |
Black level. The floor everything else is measured on top of. | 1 |
Chart by chart
What each one is for
Neutral hex chart
The main color chart. Neutral gray sits at the center and the patches step outward in six directions, toward red, green, blue, cyan, magenta, and yellow. Shooting it lets colorcal see not just that the wall is off, but which way it is off and by how much.
Shoot it four times, at Value 25%, 50%, 75%, and 100%. Value is just the brightness the chart is drawn at. Walls that look neutral at full brightness often drift as they dim, and four levels is what catches that.
Open neutral-hex →Grayscale wedge
An 11-step ladder from black to white, plus a matching ladder for each of red, green, and blue. It shows how the wall gets brighter as the signal does, which is the part that controls whether shadows crush together or highlights flatten out.
One frame is enough. Leave it at the default 11 steps.
Open grayscale-wedge →Black field
Flat black, edge to edge. It measures what the wall still emits when it is asked for nothing, together with the room light bouncing off it and the flare inside your own lens. That floor sits underneath every other reading, and subtracting it is where a lot of the visible improvement comes from.
One frame, shot with exactly the same camera settings as the rest.
Open a black field →Order
The order to shoot them in
-
Set exposure on the brightest chart
Put up the neutral hex at Value 100% and set your manual exposure so the white center is bright but not clipped. Everything after this uses those same settings, untouched.
-
Neutral hex, four times
Value 100%, then 75%, then 50%, then 25%. One frame each.
-
Grayscale wedge
One frame.
-
Black field
One frame, last. It is the easiest one to forget and the one that buys you the most.
Downloading them
On testpattern.app, set the output to your wall's native resolution and choose 16-bit TIFF if your playback chain will take it. Send the file to the wall at full scale, with no scaling or resampling in between, so the patch edges stay clean.