I was wondering if there are users in this community who can help me out processing Negativ film. I think i get the technical stuff behind the module which is described in the manual (Correcting Film Base color ect.). But i would like if somebody who has a better understanding of the module can tell me what to look for when adjusting different sliders. Some questions i have:
Do you adjust contrast only in negadoctor or do you get only a good starting point (in that case how does a good starting point look like?) and use other modules?
Is it possible to do all colour correction in negadoctor or do you use other modules like colorbalance RGB (I know i have to correct for the light used to scan the negatives with whiteballance and CC)?
I am currently at work but i am happy to add a raw latter that day if it would help this topic.
I use negadoctor as a starting point and then add contrast, sharpness, colour tweaks with other modules. I could never get a decent grab of the film base because of the way I scan negatives so use the defaults and manual controls in negadoctor to invert the negative
It’s quite a while ago and I’m going to be away from my computer for a bit so hard to jog my memory. I watched some YouTube vids as far as I remember. I think Aurelien Pierre might have had one. If I get chance, I’ll have a look at the module again shortly
You may also want to read the discussion at Digitizing film using DSLR and RGB LED lights regarding initial capture of the negatives. If you can’t do individual monochromatic captures, having a backlight with R, G, and B all being strongly monochromatic (such as an OLED display) is highly useful, especially if you can adjust the backlight balance so that the red, green, and blue channels are equal after filtering by the orange mask.
Note that I’ve been focusing on attempting to recover original scene colors accurately and not on emulating print behaviors.
I’ve found that what works for me is I USUALLY have one or two unexposed frames somewhere, or a bit of unexposed film at the end of a roll. I can digitize this and as long as my backlight and camera settings don’t change, that mask sample is valid for the whole roll and even other rolls of the same film. Looks like you’re using a Nikon ES-2, I’m using JJC’s knockoff of the same product. So no mask in the borders of a frame, but I can usually find at least one frame or partial frame that is completely unexposed.
I saw your Kodak Gold post. I actually have a DCP profile for Kodak Gold 200 that can be used with RawTherapee’s color pipeline and it works REALLY well, even for ancient negatives such as Gold 400 that was shot and developed 25 years ago. However unlike your goals with doing things that were shot recently on new film to get an “analog” effect, my goals have been to minimize “analog” effects and recover original scene color as well as I can.
Yes, I’ve tried this and couldn’t really get it to work for reasons I couldn’t figure out at the time and/or can’t clearly remember now. I just ended up using the default negative settings and tweaking by eye as this seemed to work better. Thanks for the suggestion, though
It might be worth supplying a suitable image as a plawraw image and letting people use either DT or Rawtherapee. I would be interested in the result. Even though I am a DT devotee I would happily use RT for my scans if it is superior at that task.
BTW, I do much of my color corrections and contrast corrections outside of negadoctor and it helps a lot to have a relatively clear bit of negative which could be between the frames or very dark shadow regions.
I have used Negadoctor extensively, and 90% of the time I use the colour pickers without adjusting any sliders and then just move on to other modules. Here are a few tips:
Make sure to do the tabs in order, Film Corrections > Corrections > Print Properties
If you want to use any modules like Tone Equalizer and Colour Calibration after Negadoctor, make sure you move them above Negadoctor. Consider creating a custom module order for your negative work and a custom module panel
After picking the colour of your film base, go to the crop module and make sure you’ve cropped to just the exposed part of your negative. That way, all the other colour pickers in Negadoctor will default to the right size (about 90% coverage of your exposure)
For D Max, use the colour picker and make sure it looks about right. Sometimes it will pick up its value from a speck of dust, so if this happens, draw a new area around the lightest part of the image. Keep trying until it looks about right but don’t sweat about getting it perfect.
Just use the Scan Exposure Bias picker, it should be good, but if it’s not, just draw an area around the blackest part of the exposed image
Use the colour picker for Shadows Colour Cast, don’t worry if it still looks weird
Use the colour picker for Highlights Colour Cast. This is where the image should start looking like a proper image with good tonality and colours. If the colours look way off, consider using the sliders to make small adjustments and/or do the colour pickers again in the shadows and highlights respectively. Don’t waste too much time in this tab though because you will do most of your colour work in other modules.
Just use the colour pickers for Paper Black Density and Print Exposure Adjustment. Adjust Paper Grade if the overall contrast looks way off, but usually you won’t need to do much here if everything else has gone well.
Now you can leave Negadoctor. Ensuring that Tone Equalizer is above Negadoctor, make tonal adjustments to get the right contrast
Then use Color Calibration , RGB Primaries, Colour Balance RGB for white balance adjustments and colour corrections (or any other colour module, including Colour Lookup Table and soon Colour Equalizer)
Adjust image to taste for local contrast and sharpness, masking, retouching, etc.
Negadoctor is a great module but fiddling with the sliders can soon become a bit of a mess because they all interact with each other. You might also have noticed that several seem to do similar things. For example, if you want to adjust the shadow levels, which do you use: Scan Exposure Bias, Paper Black Density, Print Exposure Adjustment…? Although there is a technically right answer to this, I recommend just using the pickers in order and then adjusting your shadows/highlights, etc. in other more familiar modules, such as Tone Equalizer or Colour Balance RGB.
Hope some of that helps. Let me know if you have any questions!
Thank you all for helping my get to grips with that module. I watched aureliens video (which i should have done before starting a thread sorry )
Don’t waste too much time in this tab though because you will do most of your colour work in other modules
I think that was the main problem i had with the module. I thought i should be able to edit the image with negadoctor alone
I will share at some point how i now edit negatives. I think the most important part was to edit the image the right way before negadoctor and use negadoctor to get a decent conversion so all the editing can be done afterwards like a normal Digital image.
So here goes. This is how i edit Color Negativ Film with Darktable 4.6.0:
Prerequisites:
I scan images with a led Video Light with my dslr.
I take an image of the light source only without the filmstock.
I then take images of the negatives and make shure to get part of the unexposed filmstock in the image as well for Color correction purposes.
One needs to open the Image taken of the lightsource and determine the correct settings to make the lightsource gray. This is done with the eyedropper in CAT TAB:
Set color of film base by choosing a unexposed part of the filmstock with the colorpicker
Set Dmax with the picker and pick the brightest part of the image. Be careful this is sensitive to dustspots.
Set scanexposure bias with the picker over the whole aera of the negativ. Correct if shadows are too pale or clipped.
4.2 Corrections Tab:
Pick a area with the eyedropper in the shadow, which should be gray to correct shadow color cast. Correct with sliders if neccesary.
Pick the whole area of the negativ with the eyedropper to set the highlights white balance. This setting is sensitive to changes in the shadow color cast. If shadows get changed highlights need to be changed as well.
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