Conversion scripts

= Conversion approaches =

scripts
a few hashtags:
 * 1) imagemagick #scripts #inversion

Resources:
 * Fred's scripts Negative2Positive http://www.fmwconcepts.com/imagemagick/negative2positive/index.php
 * Jaz99's negfix8 https://sites.google.com/site/negfix/howto

inversion using free software
This article addresses a few methods to invert colour negative film scans. In particular, DSLR scans. The focus is on processing the scans themselves. What happens before acquisition is not discussed.

RawTherapee 5.7

 * do everything, except dust and scratches and final level tweaks, in RawTherapee
 * /!\ as of early March 2020, I have almost no practical experience in setting up RawTherapee. I would appreciate any comments on the various meaningful changes I could make to my workflow.
 * Prerequisite: some hands-on knowledge on Nikon Capture NX-D, for the last part where TIFF is processed and exported to JPG.

colour negative procedure

 * Note: rawpedia is useful :)


 * 1) Open RawTherapee. In the "File Browser" tab, navigate to where the file you want to process is.
 * 2) Right-click the file and choose "Open". This gets you to the "Editor" tab.
 * 3) In the panel that sits on the right, click the "colour" button.
 * 4) Scroll down to the "Colour Management" section.
 * 5) In the "Input Profile" subsection, pick the "no profile" option.
 * 6) In the "Working Profile" subsection, pick "sRGB", without any "Tone response curve".
 * 7) In the "Output Profile" subsection, since we are going to use Nikon Capture NX-D, pick "NKsRGB".
 * 8) I leave the "rendering intent" and the "Black Point Compensation" as they are.
 * 9) In the panel that sits on the right, click the "Raw" button.
 * 10) Activate the "Film Negative" section. Inversion happens automatically in the preview image. ==> output preview looks nasty, as film base has not been compensated for, yet.
 * 11) For further tweaking, if you have such reference points in your image, click the "Pick white and black spots" button and with the eyedropper tool you now have, pick one neutral highlight and one neutral shadow. ==> output preview undergoes subtle changes.
 * 12) In the panel that sits on the right, click the "colour" button.
 * 13) Activate the "White Balance" section.
 * 14) If you are feeling lucky, in the "Method" dropdown, pick "Auto". ==> output preview looks fine, now, though it is probably muted if you are working in sRGB (my initial setup was ProPhoto and colours were already vibrant).
 * 15) If you want to do it manually, you can "Pick" the eyedropper tool and sample the black border. Or any other target that is supposed to be neutral in your final image.
 * 16) In the panel that sits on the right, click the "Exposure" button.
 * 17) In the "Exposure" section, right after the sliders, you may have already tone curves set up. Set them to "linear" and "standard".
 * 18) If you want to proceed to curves and levels adjustments, "Auto Levels" can give you a good place to start, to stretch the overall contrast. Note: I have not decided if it is as reliable at the auto WB
 * 19) Then play with the sliders and the curves.
 * 20) Quite possibly, there are many options you can play with, for most of the colour adjustments. The flexibility it offers is literally overwhelming.
 * 21) In the panel that sits on the right, click the "Detail" button to adjust sharpening. The "Transform" button allows you to crop, straighten...
 * 22) Proceed to saving the file to TIFF (floppy disk icon on the bottom bar, on the left of the main screen)
 * 23) Open this TIFF file in "Nikon Capture NX-D"
 * 24) do the dust and scratches,
 * 25) do the final adjustments to your levels (e.g. with RGB curves, ...)
 * 26) convert to JPG.

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