Brightness Calibration Screen Problematic

[jolly copper]

Hello!
I want to create a screen to calibrate brightness in the game for different screens and hardware setups of the players. (see screenshot)
But i have the problem, that low values (like when the rune is nearly black) cant be changed smoothly.
The color is "jumping" as soon as a threshold value is exceeded.
I dont know how to deal with that.

Does anyone have an idea how other games do this?
My approach is to have a png with 3 runes with different colors RGB 30/30/30, 17/17/17 and 5/5/5.
The Slider adjusts the Gamma of the game via postprocessing.
But the closer the darkest rune gets to black, the more the color jumps and its not possible to make the image "barely" visible.
It jumps from "well visible" to "invisible" within a single step like from -.20 to -.21.

[tall rune]

Is the video meant to show it jumping between visible and invisible?

[jolly copper]

yeah. But i figured out, that even that is not working depending on screens.
I also cant see the change on my second screen 😄

[jolly copper]

But i guess its just because of the low threshholds and to dark colors

[tall rune]

Not totally sure
It remains visible on my screen regardless of the gamma

Which seems to indicate that your own display has darker settings

But also, video compression muddies the waters here because the darker something is and the smaller the change between frames, the more likely the video is to use the color from earlier frames

So the video may show the rune there even if it's become fully black in reality

Something that affects this in unity is if you're using gamma space, the colors are more compressed
Also, if HDR is not enabled

[jolly copper]

on my screen its completly gone ^^

right now i tried a different approach

[tall rune]

Maybe also the LDR grading mode can make the problem worse, which is separate from HDR rendering

[jolly copper]

didnt find any setting to use hdr on that images with the standard shader

[tall rune]

Not for images, but for the whole project

If you're using linear color space and HDR rendering, I'd try dithering on the camera also

It should help with situations like these
When the screen color is between two color steps that your monitor can display, it shows both colors with a moving dither pattern to get the inbetween color

But beyond all this maybe your slider isn't that great
It's stepped in a way that seems detrimental

I'd do away with stepping entirely for the slider

If you need more accuracy in one end of the slider, for example more care when picking between very dark values, you can map the slider to an exponential curve

Which makes it more precise for picking values from one end of the range

[jolly copper]

i have HDR activated in URP Asset and in the camera.
Does the stacked overlay camera inherit that HDR from the main camera?
How can i activate the dither you mean?

[jolly copper]

i think most people stay in the middle part of the slider, because the outer parts will be rarely used, i think (and hope 😄 )

[jolly copper]

cant get dithering to work

[tall rune]

Dithering requires linear color space or HDR rendering, or both
The renderer has to generate those inbetween colors in the first place to be able to simulate them with dithering

[tall rune]

Correction, HDR is per-renderer
Linear color space is per project

Also, I'd try to verify its functionality with 3D lighting
The kind of dim gradient where banding issues occur

In your example it may be that issues with post processing are compounding

Or may something to do with UI rendering

[jolly copper]

i figured out. It works, but not in the UI cause the UI is completly on an overlay camera

i now rendered the whole UI on the base cam, but the stepping effect on the nearly black rune didnt change