DIY Drum Scanner?

[Pere Casals]

Drum scanners do not use lasers.... the later hi end ones used rather costly xenon lamps.

Not all the drums illuminate with lasers, I had to say "best drum scanners" illuminate with lasers, sorry.

"Drum Scanners spin your original Film around on a drum while a fixed laser or other beam of light looks at the Film as it spins."

http://www.spectra-imaging.com/drum-scanning.html

[calebarchie]

I think is a common misconception, I am not aware of any that use laser sources. Can you provide links or model?
I don't think chromagraph pictured has laser.

[Ted Baker]

It is an interesting discussion that would apply to all types of scanners. Do you just need good output at the optimum r, g, b frequencies for the receptor, or is a smoothly continuous spectrum better?

IMHO the spectral response should match the target, i.e. the eye or a print film (which is slightly different I believe). Its a complex problem and I don't think there is an easy answer, because too much overlap and you will see more cross talk than the eye would see. I think It becomes more difficult to model when you consider the non-linear response of film. In particular print film where the gamma is substantially different from real life, it being about -0.6 instead of +1.

My casual interest is studying/developing a solution to invert print film so I am interested in the additional complexity this entails, but hopefully they are still making e-6 materials by the time this project is finished

[calebarchie]

Nvm, that was an imagesetter..
After some digging, found the chromagraph S3400 (pictured) uses an osram 12v 50W halogen - not dissimilar to the ones in my drum scanner.

[Patrick13]

At this point it's going to be far better to design a laser driven system using mirrors for the movement across the film and avoid that whole spinning wheel of death thing altogether.
You should probably aim to make the scanner "More Human Than Human(tm)" instead of trying to replicate ancient technology.

Just an opinion

[Rich14]

" . . . instead of trying to replicate ancient technology . . . "

. . . is the key to this discussion.

Drum scanner technology was a wonderful application of extremely precise mechanical and electronic control using the best of last century's tech. But even using moving mirrors and lasers instead of rotating metal/acryllic drums to scan film is archaic.

The nano-precision of step and repeat lithography creation of high-density digital sensors and the application of those stationary sensors for acquisition of film images is, IMHO, already superior to that which we used to obtain from rotating scanners.

With a drum scanner, all the precision necessary for the mechanical process is required with each and every scan. With a digital sensor, the necessary precision is "baked into" the creation of the sensor, once, leaving the system forever free of that overhead.

And digital sensor manufacture and software processing of images is but in its infancy.

Rich

[Adam Long]

After starting this thread, I stumbled upon two ScanMate 5000 scanners. Not to far away of my home town. I took a look on them on Sunday and consider to buy both of them. One is broken, but the current owner thinks it should work, after fixing some damage done during transport. The second one is in working condition. I could use one to scan for now, have the second for spare parts and also as base for the DIY scanner project. We the working one (preview, focus and white point calibration), but could not do any scans, as the software lacks a dongle and we could not figure out how to get into demo mode. Next Sunday I will know more, as I bring my own old computer with SCSI connector to test...

I'd recommend you buy them.

I did exactly the same five years ago - £240 for one 'working' and one 'broken' Scanmate 5000, with four drums in varying condition. I couldn't test either machine so it was a gamble.

Thankfully there is an excellent Scanmate resource on the rangefinder forum:

https://www.rangefinderforum.com/for...d.php?t=139096

With the aid of that I soon had both working great. It was clear from the interiors that the 'broken' machine had had much less heavy use, so that is my main machine. The main issue I had was getting a mounting station, took me a few years and cost more than the scanners.

I'm sure you'll learn a lot tinkering with these scanners, they are very nicely made, compact and quiet. And the results are excellent.

[calebarchie]

At this point it's going to be far better to design a laser driven system using mirrors for the movement across the film and avoid that whole spinning wheel of death thing altogether.
You should probably aim to make the scanner "More Human Than Human(tm)" instead of trying to replicate ancient technology.

Just an opinion

Flying spot scanners have been around for a long time too...

[barnacle]

Indeed; flying spot telecine using a raster generated on a cathode ray tube is (was) a common way of turning both still and moving images into TV signals.

Regarding lasers, as discussed above - if you're going to do it that way you'll need a red one, a green one, and a blue one. Because you're looking for absorption at the specific colour, not at a position. I'd assume, for the same reason, that the halogen lamp approaches have very good filters between the light and the film.

Neil

[Ted Baker]

Just doing some light bed time reading, Hunt's "The Reproduction of Colour". I can't find the quote now but in it he talks of the difficulty of matching the spectral response with a sensor. In particular where colour couplers are used in a negative. The dyes spectral response then tends to be sharp cut on one side (towards red), and not so sharp on the other, though I think this also applies to transparency but not to the same say degree.

IMHO for a transparency if you can mimic the spectral response of the eye your probably gold. A DSLR is probably very good at this and will just get better.