Posted by zdw 12/28/2025
This seems more a limitation of monitors. If you had very large bit depth, couldn't you just display images in linear light without gamma correction.
Why exactly? My understanding is that gamma correction is effectively a optimization scheme during encoding to allocate bits in a perceptually uniform way across the dynamic range. But if you just have enough bits to work with and are not concerned with file sizes (and assuming all hardware could support these higher bit depths), then this shouldn't matter? IIRC unlike crts, LCDs don't have a power curve response in terms of the hardware anyway, and emulate the overall 2.2 trc via LUT. So you could certainly get monitors to accept linear input (assuming you manage to crank up the bit depth enough to the point where you're not losing perceptual fidelity), and just do everything in linear light.
In fact if you just encoded the linear values as floats that would probably give you best of both worlds, since floating point is basically log-encoding where density of floats is lower at the higher end of the range.
https://www.scantips.com/lights/gamma2.html (I don't agree with a lot of the claims there, but it has a nice calculator)
If you kept it linear all the way to the output pixels, it would look fine. You only have to go nonlinear because the screen expects nonlinear data. The screen expects this because it saves a few bits, which is nice but far from necessary.
To put it another way, it appears so dark because it isn't being "displayed directly". It's going directly out to the monitor, and the chip inside the monitor is distorting it.
More importantly, the camera isn't recording blinding brightness in the first place! It'll say those pixels are pure white, which is probably a few hundred or thousand nits depending on shutter settings.
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Really good article though
Computer imaging is much wider than you think. It cares about the entire signal pipeline, from emission from a light source, to capture by a sensor, to re-emission from a display, to absorption in your eye, and how your brain perceives it. Just like our programming languages professor called us "Pythonized minds" for only knowing a tiny subset of programming, there is so much more to vision than the RGB we learn at school. Look up "Metamerism" for some entry-level fun. Color spaces are also fun and funky.
There are a lot of interesting papers in the field, and its definitely worth reading some.
A highlight of my time at university.
> Sensor data with the 14 bit ADC values mapped to 0-255 RGB.
But anyway, I enjoyed the article.
1. Not all sensors are CMOS/Bayer. Fuji's APS C series uses X-Trans filters, which are similar to Bayer, but a very different overlay. And there's RYYB, Nonacell, EXR, Quad Bayer, and others. 2. Building your own crude demosaicing and LUT (look up table) process is ok, but important to mention that every sensor is different and requires its own demosaicing and debayering algorithms that are fine-tuned to that particular sensor. 3. Pro photogs and color graders have been doing this work for a long time, and there are much more well-defined processes for getting to a good image. Most color grading software (Resolve, SCRATCH, Baselight) have a wide variety of LUT stacking options to build proper color chains. 4. etc.
Having a discussion about RAW processing that talks about human perception w/o talking about CIE, color spaces, input and output LUTs, ACES, and several other acronyms feels unintentionally misleading to someone who really wants to dig into the core of digital capture and post-processing.
(side note - I've always found it one of the industry's great ironies that Kodak IP - Bruce Bayer's original 1976 patent - is the single biggest thing that killed Kodak in the industry.)
(I also just realised that the world become more complex than I could understand when some guy mixed two ochres together and finger painted a Woolly Mammoth.)
Our brains are far more impressive than what amounts to fairly trivial signal processing done on digital images.