The issue with LEDs, is very pure colors. That’s actually a bit of a problem, with film scanners. You need a smooth curve, and it needs to extend out a bit. You don’t want areas of color being missed.
The Coolscans had a light color response (think the “levels” screen, in Photoshop) that looked like three steep hills, with minimal overlap, but they were able to make them wider than a “pure” LED. Coherence is a feature of LED lighting.
Most previous light sources used filters over a white light, and they looked “sloppier,” with a lot more overlap, so there was more coverage. We had to correct for the unusual color coverage of LEDs.
One of the things that the Coolscan did well from a hardware perspective was that it made the transport sprocketless which allowed damaged film to be easily scanned, and it also allowed non-standard formats to be scanned easily as well. I’m curious if they have a sprocket driven system for this or if it utilizes a similar system as the Coolscan - I’ve used many scanners and the Coolscan is still the best/most convenient because of being able to just sequentially scan an entire roll of negatives.
I assume the LEDs were matched to the typical pigments used in films though? Because otherwise metamerism just wouldn't work, RGB mixed to some CCT is not white light and can't illuminate arbitrary pigments with any kind of good color reproduction.
I assume so. The folks that designed the scanners were no slouches. I suspect that they never completely turned off any LEDs, so there was always some deliberate “slop.” With LEDs, however, you can explicitly control that. They probably had some kind of filter, also. I never took one apart, though.
I got the response curves by feeding in a special slide with a diffraction grating.
The curves were markedly different from an incandescent light source.
It seems like folks buy a used Coolscan, scan their stuff, then sell it. They seem to last pretty well. I'm about to buy a used one to scan my Dad's old slides. And then sell it.
The slide feeder is good but it's worth being aware that if you have slides mounted on cardboard (I had a lot of old family photos like this I used it for) it will often grab a couple at once. You can fix that by clipping eg a driver's licence in the right place to narrow the gap it pulls the slides through, but it will still need some manual supervision.
If you get one, have a look at VueScan on the software side - the original software needs (I think) a Windows XP virtual machine to drive it.
They also sucked. I had an LS-2000 and the images were noisy as hell and it couldn't scan negatives for shit. I sold it on eBay. It's incredible how overrated the Nikon scanners were.
In the end I found a new in-box Minolta Dimage Scan Elite 5400 II, pretty much the end of the line for film scanners. I haven't tried it yet!
The 4000-5000 series Nikon Coolscans sell for about the same price they did 20 years ago because they still produce excellent scans and there’s nothing quite as good for that $1000-$15000 price out there.
