sRGB = gamma 2.2 ?
sRGB is not a gamma 2.2, it’s a composite gamma 2.4 with a linear part in shadows.
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Link to a readable sRGB tone transfer description:
That said, sRGB specifies a both a color gamut and tone transfer curve; one can build and use a profile that contains the gamut part but has a “unity” tone transform by specifying a gamma curve = 1.0.
Some nice web based updated documentation is coming together…
https://elstoc.github.io/dtdocs/guides-tutorials/other-resources/
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Thanks to all of you for the responses.
Having all my jpgs in sRGB, it seems that there is not much choice for me when displaying them on a tv, as only to select BT.1886 (only either 2.2 or BT.1886 are available) and try to fine tune BT levels.
Thank you for you patience with this slightly off-topic subject.
The TV would not be able to transform the images from sRGB to whatever you select for display?
Iirc, the standard is to assume sRGB for jpeg files, unless otherwise stated in the jpeg, so a tv that displays photo’s should be able to handle incoming sRGB.
The choice I have is just between 2.2 and BT.1886. The latter with some fine tuning possibility.
On the other hand, if my PC monitor (where I work with DT) is 2.2, then I should set up TV as 2.2 as well and stop worring about sRGB, becausel what I would see on TV should be similar to what I can see on PC.
Well, yes, I understood that your TV only offers that as it’s display spaces.
But, in the same way as an sRGB display can (more or less) correctly display images encoded in Adobe RBG (or prophoto RGB), it might be possible that your TV takes care of the required conversion. Iow, you pick the color space that you want, and the equipment takes care of the rest.
Similar, but never identical, unless you can calibrate and profile both your monitor and your TV screen. And there’s more to color spaces (and screens) than just the gamma, one big difference is in the primary colors they use (i.e. what exact color is represented by e.g. rgb=(100%, 0%, 0%) )
I was thinking about this as well - an introduction that walks the user through the scene-referred workflow with the short list of modules they can use to get started would help make the learning curve easier for new users. Moreover, publishing a few RAW files that users can practice on (and compare to screenshots or sidecar files in the tutorial) would be great so you can not only read about how to use the modules but actually try it yourself and compare your results to the results in the tutorial. You could have an example RAW file for different types of scenes (e.g. portrait, landscape, macro, etc) and at the beginning of the tutorial the user could select which one they want to use so that it can be targeted at that person’s particular use case. The result would be a customized tutorial for the type of photos the user plans to process in darktable to help practice and get familiar with darktable.
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That is the intention of this page: https://elstoc.github.io/dtdocs/overview/workflow/edit-scene-referred/
Your constructive criticism is appreciated.
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I have been away for awhile so I am sorry that I did not reply before. Thank you very much for your detailed, thoughtful reply. I have continued playing with dt 3.2.1 to learn more about using it, in particular using filmic rgb, tone equalizer, etc.
Your comment about running a survey to find out who the users of dt are is a surprise to me. I have never seen or heard of a survey. What percentage of the people around the world who have downloaded and installed dt participated? I asked several people who also have been using dt and none of them had seen a survey either.
Anyway, thanks again. I am still reading, watching a video now and then, and playing around with dt. Early on I could get good results most of the time and still can even though these days I generally use filmic rgb in the process, unlike before.
I get an error 404 on the link you provided.
if you’d like false colours in darktable you can do it via the lut 3D module.
Thank you!
Thanks. I assume I’d need to find a false color png for that?
I’m not in desperate need of this false colour functionality, but if it were added, I could see it being useful from time to time.
“So, the color-assessment mode has been designed, in conjunction with the grey theme, to provide a visual reference for display peak luminance (white border) and exact display middle grey (background). The most reliable way to adjust contrast and brightness is to raise the exposure until the average brightness of the picture matches the background brightness, with you picture fit in the screen (or even smaller, but never zoom-in).”
Given the above text as is provided in the FAQ and if you are anal enough then I guess you would do this for every picture, however maybe after a bit you really come to see that just exposing the overall picture well with exposure perhaps manually or using 50-60% with the autopicker globally or regionally on a selection is pretty good. You are essentially exposing to get midtones from your scene to look like midtones on the monitor. Then just use your preferred tonemapper if it is warranted and finally get the contrast and color right from the other modules… Many people barely tweak filmic at all and just let it be and then get on with the edit…