Thanks @Lars_Oksbjerre.
For clarity, the graphic above is an illustration superposition, not the actual output. Also I mistakenly wrote 5100K, the LED is actually 5000K.
Here the specs for the one I use.
My setup stops to capture at every frame, so less light intensity is generally required. Stopping the frame for capture also gives one the ability to capture each color channel (R G and B) at a different light setting, separately. The above tests were captured with separate color intensity, hence the similar levels at the waveform monitor.
Absolutely valid and I understand that most of the scanning jobs with archival images or footage shot by amateur users would require much less accuracy in conversion. I’m oddly satisfied with conversion algorithms designed for negative stock by different names in the industry. They look great to eye. The problem however is when professional colorists start to operate this footage it appears that known tools designed for Cineon conversion process start to fail miserably as initial capture methods already manipulate the curves before they were sequenced into ProRes.
Also worth mentioning that COLORS are highly subjective and people who master the actual images output are doing way more than just fine tuning pleasing image. With that said having baseline that is predictable and prone to errors in conversion process (which Cineon was designed for) is much more preferable. I can output Cineon gamma from any image sequence, but it won’t be the thing everybody expects from it.
Meanwhile most users will ask to provide a viewing LUT at least if they see raw scans, just because baseline Cineon would not give you anything pleasing to your eye. This is a culprit for broad audience, but why then every professional machine for cinema quality work does exactly that?
p.s. I’ve designed custom PCB broadband lights based of Cree XP E2 fixtures of specific wavelengths (Photo Red, Royal Blue, Green) and I’m insanely happy with how images behave. Even when scanning is only one flash capture (balanced to the sensor output though).
Speaking about faded films I feel like it’s more tricky. We should take into account the actual type of the stock we’re talking about. Faded dyes shift significantly and Vision3 would behave differently than EXR stocks or even older ones, because of the amount of cross influence between different dyes.
Additionally worth mentioning that responsiveness of negative film stock differs from channel to channel, so it requires less of Green light and more of Red light to be present and it can be tuned either by applying less current to specific strips or with just less amount of LEDs itself.
Also I’ve seen @fabriccio was using different wavelengths of red on a single PCB to use specific reds based on the film stock (positive vs negative)
Faded dyes shift significantly and Vision3 would behave differently than EXR stocks or even older ones, because of the amount of cross influence between different dyes.
In my experience, having scanned millions of feet of film, this is a non-issue. The only film that really fades is positive, and typically print at that (though there is some reversal that fades too). Negative just doesn’t, really. Some older color neg stocks look “faded” by modern standards but they’re really not, that’s just how they look. Thinking like 1980s Kodak color neg, pre-Vision series.They’re pretty washed out with lifeless color and chunky grain, and always were.
