Now we reach the point to turn ON the Film Negative tool. When you do this it will automatically white-balance the picture (without 20% of border and it will for now ignore any crop you did). Now this white balance step is also not good, because it depends on the content of the picture.
The better way is to use the black unexposed strip in the middle together with the white balance picker from the Film negative tool. This way we get the correct white-point of the film itself which does not change for the whole roll of film. You also can see how the “Input RGB” values are different and the Output Level changed too.
Next we set the output level to a higher value but not too high as it can blow out the whites of the picture.
The last important step is to adjust the Red Ratio and Blue Ratio to balance the film and get neutral grey and consistent color in the highlights like the sky (especially clouds should be neutral grey). Keep in mind that you should do this in a picture preferably with outdoor natural daytime lighting. The Film Negative tool contains a color picker for this “Pick Neutral Spots”-Button. When you activate this button first click one time in a bright neutral spot of the picture (but not an over-exposed part) and then click another time in a dark neutral spot in the picture. This will then set Red and Blue ratio for you. From there you can further tweak it manually to get a good result. The waveform graph can be helpful for that.
If you don’t have good bright and dark neutral spots in your picture just copy the processing settings to another picture to do that. Something like a grey road, white clothes, deep shadows and so on are helpful.
At this point you can copy and paste the processing settings to all other pictures of your scanned film. You will get consistent colors and true neutral blacks (except they have a tint from the lighting of the scene). If your negatives are under- or overexposed you can recover quite a lot by adjusting the Output Level and Reference Exponent of the Film Negative tool to change contrast and brightness in the picture and also use the Cool/Warm slider of the Film Negative tool to compensate for white balance shifts in your image due to different lighting of the scene (like indoor tunsten, outdoor evening, overcast shots and so on and use the Magenta/Green slider to correct color shifts due to older fluorescent lighting of the scene. You also can use it as a creative tool to make the film look more “filmy” by messing with the colors…
Keep in mind to not change the exposure of your camera that takes a picture of the negative. You won’t be able to recover more highlights or shadows but instead you change the white balance and mess up the colors.
The reason is that your camera can fully capture the full dynamic range of a negative image in one shot (using RAW)
With this workflow (white balance on unexposed film and change Red ratio and Blue Ratio) I can try to process the negative image from @Rick . But because it is not from a RAW file and I don’t have the correct camera input profile it is still a bit off…
in the Any interest in a “film negative” feature in RT ? thread, I don’t recall getting a simple explanation why this step is important and how it actually affects the inversion, down the processing pipeline.
If you can comment on that, I’d appreciate!
Thanks.
Yes. Make one of your own, ideally with a transmissive target, for your particular light source.
If you use the white-balance tool from Film Negative it uses the RGB values after the white-balance was done from the RT pipeline. If you use the camera auto white-balance or RT auto white-balance then when copying your processing settings to a batch of pictures from the same film you could get variations in white balance which might be disturbing.
Oh you are right. Somehow I didn’t realize you can actually deactivate it
But there is one benefit. The RT white balance works much better in correcting strong shifts in the white balance of the scene. Lets say very warm tungsten light is the light source. You can correct this after picking your white balance spot within Film negative tool.
Also i had problems before with Kodak Vision 500T film because its a Tungsten Balanced film. If you shoot in normal daylight and follow the guide then it’s very hard to use the red/green slider to get anything that looks realistic.
But using the RT white balance after selecting my film base white point you basically can change the film to be daylight white balanced (or think of it to virtually change the background light source to be more “warm” or “cold” color)
After this use the red/green slider to set the colors. I was surprised how well that actually worked.
Thats why i use the profiles from Canon for this that i got from that link. The default DCP profiles for Canon from RT cause weird color shifts when using ProPhoto color space. They work better with AdobeRGB when using Film Negative tool. Don’t ask me why.
Ok, 9 months later, I’m coming back to this. I am uploading the RAW file along with the PP3 file in case anyone wants to take a stab at it. This frame was scanned with a Fuji X-T20 and Vivitar 55mm f/2.8 macro. Scanning bed (backlight) was a Digitiliza+ and I manually set the camera WB to 6600k. In RT, I set WB to Camera, used the custom color profile from the X-T4 (Provia) and adjusted from there. I will upload that custom file as well. If you’re successful with making adjustments, let me know what you did. TIA.
I looked at the .RAF file for curiosity. But I see no piece of film-strip colour in there? The digitalize+ blocked it all? How do you know the filmstrip colour / blackpoint then?
This is what my CLI tool autodetects without having a filmstrip to scan. (It searches for the brightest spot then).
What you see here has the exposure raised a bit (and then highlights lowered to keep the detail in the clouds). This is without any custom profile or anything. (Loaded the file up into Rawtherapee, switched to neutral, rec2020 linear output, cropped to just the picture to get something that resembles a scanned .tif file, and this is what I got… isn’t that wrong, right?).
No clue what the original scene or the filmstock should look like ofcourse.
Excellent points. Yes, Digitaliza+ uses a mask that can block out the rebate part of the film. Fortunately, I can remove the mask and scan the entire frame, including the sprockets. Does the Film Negative tool allow for clicking/sampling that area? If so, I’m not seeing it.
Correct. It’s actually Kodak ProImage 100. RawTherapee does not have a profile for common color stocks, of course, so the best one can do is know the characteristics of a given film and go from there.
I agree with you that it’s much easier to get a good result using “Auto-matched camera profile”, and in fact i have a question: why the custom DCP profile you were trying to use is called “Fujifilm X-Pro3 …”, when the image has been taken with a Fuji X-T20 ? Isn’t that a profile for a different camera?
Also, since the DCP file name ends with “Provia”, i suspect it’s doing some hue mapping to convey a specific “look” to the pictures, which could throw off the inversion process.
So, here’s my procedure:
open the raw file in RT
in Color Management, select “Auto-matched camera profile” and check all three flags: Tone Curve, Base table, Look table
turn on Film Negative module
click the “Pick neutral spots” button, and pick:
the over-exposed reflection on the back of the headlamp (see below): this is a lucky spot, as it’s the most dense spot in the entire neg
the shadow area under said headlamp (see below). The shadow area on the steering wheel could also do.
click the “Pick white balance spot” button, and pick the whitest spot in the cloud (see below)
adjust the “Output level” slider to brighten the picture
adjust the “Reference exponent” slider to boost the contrast
use “Tone curve 1” just to stretch the histogram (just quickly set the min and max input values, no actual “curve”)
finally, in L*a*b* Adjustments, raise the Chromaticity slider to boost the colors just a bit.
I assume these are John Deere tractors; here’s a random picture i googled for comparison:
… the color seems pretty similar
Regarding your question:
You can do that with the usual “Pick neutral spots” button, choosing a spot of unexposed negative as one of the two spots (the other one should be a dense spot, which was white or light grey in the original scene)
Yes. While it works great for regular RAW images, it doesn’t do so well on RAW film scans. You might see that I’ve corrected my procedure in the next comment.
Yes, and there’s also an assumption that the green in your found photo is accurate. It looks pretty close to me. I’ve also since made a few adjustments that I didn’t post here. Specifically, I cooled town the overall WB significantly. Thanks for the rest of your commentary, I’m pretty happy with the workflow that I’ve acquired in this process.
Hello, I have also achieved good results following your method, but there are a few parameter settings that I don’t quite understand and would like to ask you about:
In the white balance module: I read in another article about the film negative module that I should use the selection of the light source (where the film doesn’t cover) as the neutral point. Is that correct?
Regarding the strategy for selecting neutral points in the film negative module: one should choose a point with the highest density (such as overexposed areas or spots in the image). What about the other point? I see in the images, it’s selected from black objects in the shadows (now totally underexposed black , right?).
Yes, it is correct. Please keep in mind that the white area where you pick your WB spot should not be near clipping. So, it could be a good idea to take a separate shot of the backlight only (without the negative), with a lower exposure.
You can then use the same WB values for all negatives “scanned” with the same backlight and digital camera.
Ideally, you would not pick a spot with the highest density, but rather a spot that was white in the original scene. And another spot that was black.
Or, more generally, two spots that were two different levels of gray, as neutral as possible.
It can be difficult sometimes, because you may not have two neutral spots in the same picture. But if you have another picture in the same roll that has them, you can convert that one first, and then copy/paste the processing profile to the others.
Thank you for your explanation. I want to ask if there is a recommended approach for adjusting contrast?
Currently, I have noticed that the built-in bundled profiles “film negative” uses an “S” curve in the exposure module’s tone curve (I have been emulating this method).
However, in your recent example, you utilized tone curve in color management camera profile( maintaining a linear tone curve in the exposure module), along with the reference exponent in the film negative module. So, I am wondering, do you currently recommend the latter method more?
It looks pretty close to me. I’ve also since made a few adjustments that I didn’t post here. Specifically, I cooled town the overall WB significantly. Thanks for the rest of your commentary, I’m pretty happy with the workflow that I’ve acquired in this process.