I’m using LumaRiver to make a reproduction icc profile, but I can only save the reference image in sRGB, is it possible to do it in AdobeRGB or ProPhoto?
I don’t have Lumariver, but I use dcamprof, the command-line engine behind it…
Looking at the manual, in the Profile comparison tab, there’s some kind of opportunity to “Export a TIFF Image”. The two lines from the manual:
Purpose: export a TIFF image of the rendering shown in the image view.
The exported image will be 16 bit and have the ProPhotoRGB ICC profile embedded.
Edit: Oh, welcome to discuss.pixls.us. I think you came to the right place, I don’t know anyone who specifically uses Lumariver, but there’s a lot of color knowledge here and a few of use who know dcamprof.
LumaRiver is a paid product and one would assume that support comes with that, you should ask the vendor.
I mean saving the reference image in rawtherapee that is then used in LumaRiver.
The reference image is not saved in sRGB - it’s linear in camera-native colorspace.
It happens to also not be tagged with any ICC metadata, so a lot of software will (incorrectly) assume it’s sRGB gamut AND sRGB gamma - Reference TIFFs are not tagged with an ICC profile that indicates linear data · Issue #5575 · Beep6581/RawTherapee · GitHub
Lumariver is basically a GUI frontend to dcamprof, the reference image should work. dcamprof+scanin has no issue with the ref images themselves (it appears to assume untagged high bitdepth TIFFs are linear and not sRGB gamma), the only reason I filed that particular issue is that if you need to preprocess the ref image (defishing in Hugin) or load it in GIMP to pull fiducial coordinates (I think scanin’s autodetect is too unreliable), you need it to be tagged as linear.
I don’t know how dcamprof will behave if you feed it an image with an ICC profile attached that indicates anything other than linear. It kind of defeats the purpose of dcamprof - if you’re running it, it’s safe to assume that you don’t know what the profile actually is. It definitely ignores gamut information, it may possibly pay attention to gamma information if it’s something other than linear.
As Andy noted …you want a linear image with no profiles to feed Lumariver…its basically a GUI for dcamprof so all background info from that software should apply… I do recall some issue that someone brought up that the reference image was not actually doing what it was supposed to…does anyone recall this… I will go back an dig it up…
Basically you make these images in DT by setting all the profiles the same so the image passes through un altered… usually this mean all linear rec2020. The save reference image is supposed to save the image before the input profile is applied in RT I believe so that you get the linear camera space image to feed the software… so no color profile stuff… maybe as Andy said Luma is having a problem reading it??
I think this is the one I recall which was ART not RT
Ah, got it. So, you’re talking about RawTherapee’s “Save Reference Image” described under Color Management in RawPedia:
Hmmm, so you’re saying that linear TIFF is saved with an embedded sRGB color profile, or sRGB tag in the metadata? That’d be weird, as the first sentence says, "Clicking the “Save Reference Image” button saves a linear TIFF image before the input profile is applied. ", meaning, the image data is still in it’s original state from the raw file. It may be that it is, but RT is just embedding or tagging it inappropriately.
Thanks for the indepth answers, and it actually makes sense. Where I think it went wrong is I opened the file in photoshop and it said it was sRGB, but it probably changed it when it opened the file.
Ah…it does make more sense as I was trying to recall where you would be using that in Lumariver…you can set this in there for previewing how your rendered profile will look for a selected color profile if I recall but your Tiff should import just fine
@thomaasss The most important thing is to know the difference between Assign and Convert in PS. What you want to do is assign the profile. That tells PS what the data is about if it cannot detect the profile properly or it isn’t available. In this case, use the linear profile from RT or your camera. (I don’t quite remember which is it for the reference image.)
Nope - right now (see the issue that I linked), it’s saved with no profile. Lots of software assumes that this is sRGB gamut/gamma (and the assumption in this case is wrong).
Per the issue described, another approach (similar to the one @priort described) is to set:
No input profile for camera
Working profile gamut matches output gamut
Output gamut set to linear (RT sadly makes this really hard to do currently, you can’t easily use anything generated by the ICC profile generator as an output profile without manually installing it to the RT system profiles directory, which needs root access unless you installed to a custom location, unless I’m missing something. If Roel or Ingo confirm that this isn’t a problem between chair and keyboard, I’m going to look into making this less painful as a post-5.9 task.)
Pretty common behavior for images that lack a profile.
That linked change from float to int is interesting - because some software (Hugin for example) will (mistakenly) assume that floats in a tiff file are linear, regardless of any ICC profile stating otherwise.
Indeed, it is quite the mess: a lot of software assume things about the file depending on the file type, data type, range, tags, etc. G’MIC disentangled that for me since it only cares about the pixel values, but that presents the problem of not being able to take advantage of information such as profiles for colour management and other metadata that would inform the post-processing and archival workflow.