Any interest in a "film negative" feature in RT ?

ahhh thanks Alberto, that opened the latest version and I see the Film Negative option. I’ll give it a go.

Cheers
Matt

Well done!

Yes, you fetched the “normal” track, which is what the majority wants.

In this link,
http://rawpedia.rawtherapee.com/Linux#Debian.2FUbuntu.2FMint.2Felementary_OS
go down to subheading Choose a branch. You just have to pick another starting point for your compilation.

In your case, the branch to fetch is capture_sharpening

So, to recapitulate:
git branch -a
will show you all branches available.

Using
git checkout capture_sharpening
will tell your setup the branch to use.

Then just compile it, just like you did with the standard branch.
(See subhead Make in the link above.)

Have fun!
Claes in Lund, Sweden

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Alberto,

I am not sure it is coping with the EM5 mkii hi res images? Is there a way for me to send you a sample Raw file to test?

Cheers
Matt

old manual way

Sure, upload it here:

https://filebin.net

and send me the link, i’ll take a look.

Edit: in the meantime, i’ve tried with a sample RAW file grabbed from dpreview:


…and it seems to work ok.

Maybe i guessed why this happens: looking at your thumbnails, it seems that the actual negative area is very small compared to the whole picture. This way, the auto-gain feature in the film neg tool is biased by the large amount of the empty “border” pixels.
Can you zoom in a little bit more with your lens? Otherwise, just compensate by raising the exposure slider.
Anyway, if you send me the raw file, i’ll check

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thanks very much for the patience. I also went down to the lab and did another negative scan (digitisation) with a normal RAW setting and I got the same result. Either I am doing something wrong or there is a problem with the Olympus raw files.

https://filebin.net/dfxe28t7zl6qcljv

Yep, confirmed, the calculation is biased by the large empty area around te picture, and brings gain down too much. I’ll have to figure out a way to detect these situations and Do The Right Thing.
In the meantime, if you can’t avoid working with such small crops, here’s a quick and dirty workaround or you:

  • Lower the Reference exponent to the minimum setting, like 0.3
  • Boost the exposure, and spot-WB on a white/gray element of the picture (i see that your film holder completely hides the film border around the frame, otherwise you could use that, too)

Here’s what i’ve got:

and, here’s the relate .pp3 with the settings i’m talking about:
P8316416.ORF.pp3 (11.2 KB)

Hope this helps :wink:

alberto

Edit: actually, this one is better, i had completely missed the color balance :smiley:
P8316416.ORF.pp3 (11.2 KB)

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thanks Alberto, in my normal process I would do a Crop on the image before starting work on any other settings. I wonder if it’s possible to get the Negative plugin to work within the bounds of that crop?

Cheers
Matt

Such a thing has been proposed before: https://github.com/Beep6581/RawTherapee/issues/709 (see at the bottom). It hasn’t gained much traction for a while…

Yes but then, if one adjusts the crop after processing the negative, the tool would re-calculate channel gains, shifting everything around and destroying all the previous fine-tuning…
I have to think about it, maybe i could just add some “pre-crop” parameters specific for the film negative tool…

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Ping @heckflosse en @Hombre, as they have been working on the https://github.com/Beep6581/RawTherapee/issues/4263 rawcrop branch in the past.

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being able to specify the area to take the exposure values and white balance from would be really useful if it’s possible. There are so many film formats and only two digital sensor sizes, 3:2 and 4:3. I regularly shoot, 6x12, 6x9, 6x7, 6x6, 6x2.5, 3x2

Possibly a “region of interest” selection within the negative tool?

Disadvantages: Potential duplication of code vs. calculating after crop
Advantages: Not getting thrown off by later crop adjustments as you mention

Perhaps even the “ROI selection” tool could have some method of clicking a “Calculate ROI from crop” button?

Yes, i was also thinking about adding a button to re-calculate multipliers. I wouldn’t add a dedicated ROI selection tool, instead i would just add a single button labeled “Re-calc multipliers from current crop”; this would be based on the usual crop tool, but would alter the multipliers only when intentionally clicked.

Anyway, i would also like to revise the whole “auto-gain” concept, because i think it has some flaws. For example, let’s say you’re walking down the road and you shoot two pictures, a few minutes apart, both in the same lighting condition. In the first one, the frame is dominated by a big green tree. The second one is dominated by a big red wall. Everything else (the road, the sky, etc.) is the same.
Ideally, you would process these 2 pictures with exactly the same WB values, since lighting is the same. With the current auto-gain feature, instead, in addition to being skewed by the empty film holder area (as @matt_jones discovered), the channel gain is also skewed by the image content. After setting the perfect WB values on the first picture, if you then copy/paste the processing profile on the second one, you’ll find that you have to re-balance it, yielding different WB values than before. This is not a major issue (you can quickly spot-wb on the grey paved road), but i find it a bit annoying, especially if you have to process many negatives and you want to “industrialize” the process as much as possible.
So, i was thinking about saving the multipliers in the .pp3. This could be a working solution:

  • when you enable the film negative tool for the first time on a picture, and the multiplers are not set, they are calculated automatically and saved to the pp3
  • if the image is too dark, or you’re not happy with these multipliers, you set the desired crop, and hit the “Re-calc multipliers from current crop” button. The new multiplers are saved to the pp3. Now you can even select a different crop area, multiplers won’t change.
  • now you fine-tune Exposure and WB to taste; when done, you can copy/paste the processing profile on the entire roll, and all pictures with the same lighting will have consistent color balance, regardless of the content.

I’ll try to experiment a bit… opinions appreciated! :wink:

Hi, I’ve discovered this feature via dpreview. Long time ago I developed a simple bash/imagemagick script to invert any C-41 scan into the positive image. Maybe it can be useful in this case.
Sample images: https://www.flickr.com/photos/tags/negfix8/

Script to download: https://sites.google.com/site/negfix/
Hope you find it useful.

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Nice. I did notice the “no holder fragments” restriction - that can be a major hassle. One of the nice things about the new implementation from @rom9 is that at worst case, holder or hole fragments will throw off the white balance premultiplier mechanism, which is easy enough to fix with the white balance module. (See our discussion regarding region of interest settings and/or taking crop into account in order to make this more consistent.)

I’ll have to take a look at the script in more detail later.

Does the new feature “film negative” work only for raw images from digital cameras?

I loaded a negative scan from my scanner and the RAW tab is disabled.

Hermann-Josef

Yes. See the docs.

What is the Favorites Tab Options File name for Film Negative please? I like to add all the Modules I don’t use often to this tab, just for my workflow.

filmnegative

Thank you