> A fun tangent on the "green cast" mentioned in the post: the reason the Bayer pattern is RGGB (50% green) isn't just about color balance, but spatial resolution. The human eye is most sensitive to green light, so that channel effectively carries the majority of the luminance (brightness/detail) data.
From the classic file format "ppm" (portable pixel map) the ppm to pgm (portable grayscale map) man page:
The quantization formula ppmtopgm uses is g = .299 r + .587 g + .114 b.
You'll note the relatively high value of green there, making up nearly 60% of the luminosity of the resulting grayscale image.
I also love the quote in there...
Quote
Cold-hearted orb that rules the night
Removes the colors from our sight
Red is gray, and yellow white
But we decide which is right
And which is a quantization error.
Funnily enough that's not the only mistake he made in that article. His final image is noticeably different from the camera's output image because he rescaled the values in the first step. That's why the dark areas look so crushed, eg around the firewood carrier on the lower left or around the cat, and similarly with highlights, e.g. the specular highlights on the ornaments.
After that, the next most important problem is the fact he operates in the wrong color space, where he's boosting raw RGB channels rather than luminance. That means that some objects appear much too saturated.
So his photo isn't "unprocessed", it's just incorrectly processed.
I didn’t read the article as implying that the final image the author arrived at was “unprocessed”. The point seemed to be that the first image was “unprocessed” but that the “unprocessed” image isn’t useful as a “photo”. You only get a proper “picture”
Of something after you do quite a bit of processing.
>There’s nothing that happens when you adjust the contrast or white balance in editing software that the camera hasn’t done under the hood. The edited image isn’t “faker” then the original: they are different renditions of the same data.
That's not how I read it. As in, this is an incidental comment. But the unprocessed version is the raw values from the sensors visible in the first picture, the processed are both the camera photo and his attempt at the end.
From the classic file format "ppm" (portable pixel map) the ppm to pgm (portable grayscale map) man page:
https://linux.die.net/man/1/ppmtopgm
You'll note the relatively high value of green there, making up nearly 60% of the luminosity of the resulting grayscale image.I also love the quote in there...
(context for the original - https://www.youtube.com/watch?v=VNC54BKv3mc )