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

[nonophuran]

@rom9,
hi and thanks for your quick feedback.

EDIT: the screenshots are yuck, way over the top

to crop or…

@rom9

There is no need to crop, since the calculation works on the entire raw image (before cropping is applied).

1. ok for the crop.
2. Now what if the captured image does not have any border? how necessary/mandatory is the film base in the calculation? I am asking because in some cases - due to light bleeding through sprocket holes into the film base - it is very desirable to mask out everything that is not the image to scan in order to avoid nasty bleed into the image itself.

estimating curves

@rom9

Since we are estimating a curve from 2 points, choosing distant values should (in theory) give a better estimation.

• are we estimating a curve or merely a slope in the log domain?

contrast (Reference exponent adjustment)

I had totally forgotten to ask this. From a signal processing pipeline standpoint,

• should I strive to maximise the contrast (Reference Exponent) in the Film Module itself?
• or should I not even bother and use low values, such as 1.0 instead of 1.5, and do my contrast and exposure with the exposure section?

example:
A. film module inverts and gives me a bit too much contrast once final WB is achieved. Should I reduce the Reference exponent value? or should I play with the exposure / highlights and shadows compression sliders instead?
B. film module inverts and gives me a very conservatively stretched histogram once final WB is achieved. Should I then proceed to increasing the Reference exponent value in order to adequately stretch the histogram? Or should I just do it with curves mini. and maxi. levels?

exposure sliders

• ok, I’ll spend some time reading how the sliders work as I don’t find the exposure and blacks combination very intuitive.

DCP settings

• too bad you don’t know. Maybe people involved in this thread would know? do you know anyone in there? Also found this.

• I honestly abhor the trial-and-error approach for this kind of signal processing related issue - I need to grasp the compromises I make when I activate this or that.
  But, just so you see what irritates my eye, here is an obvious case of dull reds. The reds are not the only hues affected but they’re the most obvious in this picture.

  • “Look table” deactivated:
    

    

  • “Look table” activated:
    

    

• how I adjusted the neutral blacks, neutral whites and white balance:
  

Here’s the folder containing the .NEF and .pp3 files.

One additional example: look at the paint of the car and at the tail lights.

• “Look table” deactivated:
  
  
• “Look table” activated:
  
  

==> I am not saying it’s “perfect” without the look table but… here’s, for what it is worth, a slightly contrast-boosted iphone shot taken at the same moment: https://www.flickr.com/gp/franekn/yK3oZL

Reference:

@https://rawpedia.rawtherapee.com/Color_Management#DCP_Look_Table

DCP Look Table

This enables the DCP “LookTable” lookup table which is intended to add a subjective look on top generally together with an embedded tone curve. That is if you disable the DCP curve and looktable you may get a neutral “colorimetric” profile, if the DCP was designed that way which is not always the case (if the DCP has both a look table and a base table it’s likely that it is, but if it only has a look table it will probably not work well with it disabled). Disabling individual DCP elements are considered advanced user settings, normally you would leave this on.

anybody knows the “advanced uses” mentioned here?

Thanks for reading and, in advance, thanks for your help / pointers.