Processing profile compatibility between different versions of RT


(David ...) #21

I think this answers my basic question. This looks like it may be new material in RawPedia because I thought I was pretty well read on processing profiles. The first sentence says, “Processing profiles evolve from one version of RawTherapee to the next. We strive to ensure backward compatibility (e.g. a profile created in 5.3 and opened in 5.4 should look the same), but this is not always possible.”. I take this to mean “go ahead and try it but you can’t count on it to produce the same result.”. With respect to workflow, my interpretation is that if you want to preserve the state of the editing that has been done in a manner that either editing could be resumed from that point or additional exports made of the same result then you had better retain both the relevant processing profile and the version of RT used to create it. Based on this experiment & discussion I’m also inclined to think that one should be sure to make (i.e., save) any processing profile that is to be preserved in a way that RT will not confuse it for the ones that are automatically opened & rewritten without requesting user permission.

That leads to the question, “might it be better to export the resulting image to a file using a standard format that could then be reopened in either RT or any other image processing software?”. I think this would eliminate future ability to perform certain raw processing operations such as demosaicing. I’m not experienced enough to have an opinion about this but would be grateful to learn form those who are.

Of course the answer could also be to take both of the above actions.


(Karlheinz Lehmann) #22

If you tick this checkbox, your pp3 will be saved in addition besides your output file
image


(Morgan Hardwood) #23

In the last two or so years I noticed significant attention being devoted to preserving PP3 compatibility, but, as RawPedia says, that’s not always possible, for various reasons. One reason I could be responsible for is a DCP profile being added or changed, for instance.

That is exactly what you do when you save the final image to TIFF, PNG or JPG. I think this question is missing something to make sense.

I compress my PP3s if I feel they deserve to be safely preserved:

tar -cJf pp3.tar.xz *.pp3

(David ...) #24

Looks like this points out that when an image is saved (what I meant when I previously said “exported”) in a standard format, my comment about doing “both” is what you get. What I think we’ve learned here is that in addition it is also necessary/wise to also keep the version of RT used to do it. That works pretty good for me right now but as the number of RT versions mount and the underlying OS (in my case Windows) migrates forward to the point of not being able to run older versions this could get a bit tricky.

It would seem to me that preserving the ability to go back and resume work on a previously developed raw file would be desirable but I’d welcome the opinion of more accomplished photographers about the worth of doing so and especially for how long (i.e., how far into the future this might be of value).

Is it possible that once some skill at developing raw files is obtained that simply starting over with the raw file is good enough?


(Mica) #25

Twice a year or so, I go back through all of my raw files and look for things I’ve missed in my editing rounds. I usually find one or two images that I’m either unsatisfied with the processing I did at the time or a completely unprocessed raw file that I’ll then develop. If I wanted the output from that moment from RT, I’d just find the tiff I output at the time (I generally keep a print and web version).

So I either want what I had, which means I grab the tiff, jpg, or xcf (depending on the processing), or I want to start over. In either case, backward compatibility doens’t come into play often.


(Morgan Hardwood) #26

Skill acquired since the last time a photo was processed is one of the motivations I listed in RawPedia (in the “Compatibility” section I linked you to earlier) for reprocessing a photo in a different way should you ever happen to revisit it. Regardless, backward compatibility has been generally well taken into account these last few releases/years.


(Glenn Butcher) #27

That’s exactly what I do. And it doesn’t take a bunch of skill, just familiarity with the most-used tools. I also don’t worry about exactly re-creating a curve, or really any other tool.

Now, my workflow for informal photography starts with a raw->small jpeg batch rendition, then I review the jpegs and re-process selected ones from raw to do things like further adjust contrast or crop. But I always start from the raw. I can re-open a raw with the same processing that produced the jpeg using the processing chain stored in the metadata, but that relies to an extent on consistency between the batch processor and the interactive program. Even then there may be differences, and I just accommodate them manually.

Regarding the thread topic, it’s important to realize that most of these image manipulation tools are not engineered for consistency. In different softwares, a sharpen slider that goes from 0-10 may mean different scales, because there’s no measurement standard for ‘sharpness’. Even in successive versions of the same software consistency cannot always be maintained, depending the nature of the improvements. A ‘better’ spline algorithm for a curve tool will yield a different curve, for example.

It has been thus since early days. If you regard some of the “print plan” photographs from such as Ansel Adams, they mark the regions of the image with the appropriate manipulation instructions, e.g., “dodge 3sec” or “burn 5sec” to convey application of differences in printing light from the baseline exposure. Not said is that such instructions rely on the specific illuminator, and would have to be translated for another enlarger, or print size on the same enlarger.

If you’ve created a specific ‘look’ for a photograph and intend in the future to produce particular renditions of size, crop, etc, you probably want to create a full-resolution reference image as the starting point. If that were important to me, that’s what I’d do. It’s not so important to me, I actually like starting from scratch.


(David ...) #28

Thanks! The perspectives of more experienced photographers is appreciated.