I recently went on a trip and took a bunch of pics with my girlfriends Canon Rebel.
We shot in RAW, and now I am going to process the RAW images in DarkTable (my first time ever).
I have read that the first thing to do when processing RAW images, is the debayering of them.
I have googled it and read a skimmed a few articles, and I am still a little confused.
So if debayering is required to make a greyscale image a trichromatic image....why are my RAW images already colour?? Does that mean that the camera already did the debayering of the image?
Answer
This is actually really simple: your image is shown in color by Darktable because it renders the preview from the RAW file in order to show it to you — including demosaicing. (Or, depending on settings, it may initially show you a low-quality JPEG preview actually embedded in the RAW file by the camera.)
This is why I find the whole "RAW isn't an image; it's a collection of data!" somewhat over-pedantic. This is true of JPEG files too: "they're not images, they're collections of discrete cosine transforms!" — which is obviously also silly. The difference is that there is no fixed "correct" interpretation of the RAW data: there are many possible ones. Darktable (and any other software) shows a default interpretation when you load the file.
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