Originally Posted by
rawitz
Hm, a filmscanner varying exposure times of different colors is quite false and the rest of that post too.
I´m sorry but I have to remind what a scanner does. If a scanner (like the Epson 700/800s) has the technical specs of density 4D and 16bit/channel recording, this means: the scanner has a brightness latitude 1:1000 (=4D) which is about 10 f-stops, and within this value the brightness is scaled in about 65000 steps (16bit) from black to white, for each (!) color RGB.
After calibrating the lightsource (brightness and color of the lamp) the scanner makes a scan of the picture within his complete brightness room and renders this to 16bit, no matter you have a BW, Colorslide, oder Colorneg on the scanner, and no matter of your manual or auto adjstments in BW-Points, Brighness and Colors and else.
All this is the second step made not by the scanner, but by computing of the scanner software. This first step is the famous rawscan and as it is completely untouched, there cannot be any wrong adjustments (but also not any right). The scanning with all the three or six scanning rows for each colour is one single step, inherent is no technical possibility to vary exposure or filtering one color separately.
You can verify or falsify my statement: If the time of the raw scanning (when you hear scanner-motor working) is the same despite varying brighness, color balance or color reversal, but scanning time is varying setting dpi much higher (from 2400 to 6400) or lower, that will prove my theory.
Short results:
Extracting a CN rawscan is not faulty, but a correct way to digitize CN-Film.
Extracting the mask can be done within the scanning software, or also later in PS.
Pretuning the scan in scanning software and finetuning later in PS is quite right (this is my way).
Digitizing NC via a Camera is possible with the correct technical equipment and workflow
regards
Rainer
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