Camera board • Tonemap configuration not producing expected brightness

I'm working with a Raspberry Pi 5 and editing the tuning.json to customize image output.
I'm experimenting with custom tone mapping settings in tuning.json for the Pi Camera pipeline.
Is there any official or recommended template/example of a full rpi.tonemap block, especially for how to structure the tone_curve?

I defined the following rpi.tonemap block:
"rpi.tonemap": {
"detail_constant": 0,
"detail_slope": 0.1,
"iir_strength": 1.0,
"strength": 1.0,
"tone_curve": [
0.0, 0.0,
0.02, 0.20,
0.06, 0.38,
0.15, 0.55,
0.35, 0.75,
0.50, 0.82,
0.70, 0.91,
0.85, 0.96,
1.0, 1.0
]
}
I expect tone_curve to be like this.This tone curve is intended to significantly brighten shadows and compress highlights, resulting in an overall flatter, brighter image. I expected JPEG outputs to show lifted shadows and reduced contrast.However, the actual result is the opposite the entire image looks darker than expected, especially in the shadows.

It's possible that I'm misunderstanding how the tone curve is applied, or that I'm missing some related processing steps.
Is there any official or recommended template/example of a full rpi.tonemap block, especially for how to structure the tone_curve?
Any documentation, sample tuning files, or insights would be greatly appreciated.

Statistics: Posted by Seaso — Fri Jun 13, 2025 5:04 am

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