Adding Custom Working Profiles

[Thanatomanic (Roel)]

@XavAL

I’m sorry, but when I was a Photoshop user, I understood by the many posts, articles and tutorials I read, that a working profile, with its TRC, was meant to edit the image, and it could also be the color space (or profile) of the output image, or not . My very last step right before exporting the image was always to convert the color space to a better suited one (usually to sRGB).

I have never used Photoshop extensively, but after re-installing it, playing with it and reading this and this, I understand things better. @XavAl’s explanation seems correct. Apparently Photoshop intends for you to only pick one color space and assumes you use soft-proofing to ensure your colors will look right on your medium. Then if you don’t show the advanced options on export and pick an different color space there (the output color space), Adobe assumes your working space is your output space. This space will be embedded in your exported file.
So the key difference here is that the choices for working color space and output color space (or profile, whatever you like to call it) is more visible in RawTherapee than in Photoshop.

@samuelchia

When you talk about working space profile in Photoshop, it is always using the TRC of the working space profile, is it not?

If it does, that would be very bad for many editing operations. See here for more information: https://ninedegreesbelow.com/photography/test-for-linear-processing.html
Elle’s conclusion is that for Photoshop “Some editing operations and blend modes are automatically linearized, and some are not, and some editing operations are linearized at 32-bit floating point, but not at 16-bit integer precision.”
The key difference here is that in RawTherapee the TRC is ignored so you always operate in linear RGB mode.

@samuelchia

The Dcam spaces are not designed to do that. This is a gross misunderstanding. The Chroma Variants are what is used to increase saturation. Two very different things.

Well, agreed on the regular DCam spaces. But Holmes doesn’t advertise his chroma variants any different than his regular DCam spaces. That means he implies they are working profiles too, right? That means a look is applied, which is not what a working profile should do. But since Adobe muddles working and output profiles together, I guess you can say that things are all right in the end?

@samuelchia

To put it another way, the Dcam spaces are what you convert to just like any other regular RGB working space. The Chroma Variants are what you assign to modify the colour.

This is still something I don’t understand. Can you explain what you do in Photoshop that makes these operations uniquely different?

Edit: I must correct myself from earlier statements where I strongly advocate to work in linear RGB space. While this is sometimes true, that is not always the case. Coincidentally, there is a recent nice post here that gives a few examples of operations that you want to do outside linear space. I think that Adobe may have the philosophy “use the TRC from the working profile and work in non-linear space by default, but internally convert to linear when necessary”, and RawTherapee is the opposite “ignore the TRC, work in linear, except in some cases”.