LED Light Table?

[Pere Casals]

reasons I already mentioned.

Drew, today EPSON V850 uses a LED illuminator, with no problem. As I mentioned an additional diffuser may be required on the panel...

Spectrum will be continuous enough to make an IT8 calibration nail color accuracy.

[interneg]

A TLCI-2012 score of at least 85 is what you want - and the results have a tendency to suggest that price of the luminaire doesn't necessarily indicate the quality of its performance. It's a far tougher test than CRI.

[Drew Wiley]

Sigh ... I don't have time today to discuss all the "what if" factors. So I'll simply default to the position that a well-made lightbox will be reliable far longer than most scanners, be less complicated to operate, and cost less too. And if the OP ever wants to copy color film onto real film rather than digital capture and jumping through hoops post-processing, it has to be pegged very close right from the start.

[Pere Casals]

A TLCI-2012... It's a far tougher test than CRI.

Well... for low rating there is a difference, for high ratings usually TLCI and CRI give similar ratings:



This is for the Aputure Amaran AL-M9 DSLR illuminator

Sigh ... I don't have time today to discuss all the "what if" factors. So I'll simply default to the position that a well-made lightbox will be reliable far longer than most scanners, be less complicated to operate, and cost less too. And if the OP ever wants to copy color film onto real film rather than digital capture and jumping through hoops post-processing, it has to be pegged very close right from the start.

Yes... nothing like tungsten to throw the tungsten spectrum, but it converts 95% of the power into heat...

Best LEDs (violet source) are even better than a ceramic discharge metal-halide (CDM) lamp, and second rate leds (blue source) are almost as good as a CDM. Of course there are also very bad LEDs, but a LED sporting CRI Ra 98 deserves some respect.

[choiliefan]

Artograph LX series have adjustable color temperature: https://www.artograph.com/light-boxes/

[Drew Wiley]

I'm getting close to one of those "read my lips" moments. You don't get something for nothing. Of course, you can use all kinds of these devices. But doing accurate film copy backlighting is something much more demanding than a mere tracing tablet provides, especially if one opts to do it using film itself. Reminds me back when people would pay about fifteen bucks for a Spiratone slide copy device that looked like a black spray painted toilet paper roller; and that's exactly the kind of results you could expect - flushable.

[Pere Casals]

Drew, OP is not to expose/copy film on the table, he asks for a illumination source to scan with a DSLR.

[Alan Klein]

I tested Kelvin in five locations on my Kaiser Slimlite Plano 2453 in both battery mode and 120 power charge mode. Display portion is 6.3" by 8.7" for this model. See first image. I used my NEC Spectraview II puck and software to take the readings. The bottom image is a typical reading shown on my monitor. Of course, the intent was to take reading of the monitor but I put the puck on the Kaiser lightpad.

Beside the Kelvin reading, you get other readings. But I don;t know if those are of additional value. Does anyone know what they mean?

[Drew Wiley]

Color temp meters have integrating spheres, but can still be fooled off-axis. But IF those readings in your sketch are indeed accurate, it means the light pad is hopelessly uneven in terms of color temp, and would be useless for anything like duplicating. Doesn't surprise me.

[Drew Wiley]

Pere - if it's not suitable for film, it's going to be less than ideal even with a digital device. The whole point is accurately balanced RGB spectral peaks. Yes, one can jump through flaming hoops in digital post-correction; but there's always the risk of coming out the other side smelling like smoke.