Anyone seen the Digital Transitions film scanning setup?

[Brian Sims]

If the film is held without any contact with glass, how does the system deal with sheet film that isn't flat?

[dougpeterson]

If the film is held without any contact with glass, how does the system deal with sheet film that isn't flat?

The system allows either magnetic "no touch" carriers and glass carriers [ANR or standard].

In our testing 4x5 can be done in the magnetic carriers at low and medium resolution (e.g. 2000ppi); in such a configuration the sag of normal-condition 4x5 film is minimal as the magnetic holder and the way it is loaded provides some minimal tensioning, and fits within the DOF of apertures that aren't significantly diffracted. When doing this style of scanning it's important to set the focus using around half way between the center and corner of the frame. Of course if the film has significant inherent curl this method will not work well. Our experience is that most 4x5 film has minimal curl (at least compared to 35 and 120mm) but of course every collection is different. When curl is moderate and the PPI is not too high you can also use film-safe tape in the corners of the carrier to help gently tension the film down (if whatever stakeholders like the owner of the film or conservation team of an archive agree to it) without touching the imaging area.

At higher resolutions such as 5000ppi it is no longer possible to use the magnetic carriers with most 4x5 film; the amount of sag when supported from four edges, even with tape and/or magnet acting as a mild tensioner, is greater than the DOF we can provide at such resolutions. In such a case you should switch to a glass carrier (we have one coming out in the next quarter, or you can use any high quality glass, especially from 3rd party wet mounting stations). You can either use ANR glass and dry mount (we've tested the ANR glass we're releasing next quarter to 5000ppi with minimal detected texture) or use standard glass and wet mount. The requirement to wet mount is not as strong with our system since the light is diffuse and uncollimated and therefore renders scratches and surface imperfections with less inherent contrast (similar to lighting an older actor with a soft box rather than a 10 degree grid spot and looking at the way their skin renders). But wet mounting is still the best way to get the film completely flat without introducing any texture at very high PPIs (in theory our system could shoot at nearly any resolution with the appropriate lens selection, but at decreasing areas of view per capture).

For 8x10 film and oddball sheet film sizes we always suggest the glass carrier route, though if you just need a reference image (not a high res archival scan) you could do it with a four-edge-holding carrier.

Our system is, like most photographic devices, a tool. It can be used to solve a variety of photographic/scanning problems many of which are extraordinarily difficult to solve without our system (e.g. high res archival scanning of a glass plate in poor condition, at high resolution, without touching the delicate emulsion, or scanning collections of hundreds of thousands of images in a reasonable time table). It is, in my highly biased opinion, one of the most flexible scanning solutions as each component can be swapped out as needed for unusual problems, and a variety of workflows are possible to do the actual scanning. We also make all of the handling elements ourselves in the US, which means we can provide one off options and customizations for unusual projects (i.e. right now we're looking into a reel-to-reel holder). But it is just a tool. It's not the second coming or the best option for every application (e.g. individual photographers scanning only a few images per week at home would not benefit from this system IMO).

A lot of this is covered in the videos at the bottom of these two links:
http://dtdch.com/page/film-positioning-system
http://dtdch.com/page/media

[Alan Klein]

The big issue with flat bed scanners are the dMax spec. The ability to see through the shadow and darker areas are problematic. What is the dMax for this unit? How does it deal with these shadow areas?

[keith schreiber]

Hi Jim,

I see that you are in Tucson. The Center for Creative Photography at the U of A has one of these systems. I saw it when visiting back in early 2014, so it may be an early version. (I worked there in the Rights & Reproductions department back in the 90s when we did this sort of thing the old fashioned way. Seems like so long ago!) Joey Rheaume, who runs the digital imaging department (or whatever they call it) is a friend. Maybe he would give you a tour or even a demonstration. PM me if you would like his email.

Keith

PS to Doug: Tucson is misspelled on the client page of your website.

[dougpeterson]

The big issue with flat bed scanners are the dMax spec. The ability to see through the shadow and darker areas are problematic. What is the dMax for this unit? How does it deal with these shadow areas?

Short answer: Not a problem.

Long answer: The sensors used in a Phase One digital back are significantly more recent technology than those used in flat bed scanners. We've done a variety of comparisons as individuals test the system and so far I've not run into any materials which did not fit within the dynamic range of a single exposure. You can't prove a negative; that is, I can't say definitively there are no transmissive materials which exceed the dynamic range of the digital back (because I haven't tested every single material in the world), but I can say that we've tested a large variety of material and not seen any that do. Let's speculate and say that some scientific-application scientific material we've not tested yet had too large a range (dMin to dMax) for a single exposure; it would still be a simple matter to capture two raw files a few stops apart and use HDR Merge to combine them - the total time to create the final HDR composite would still be a minute or two.

As far as a specification go, because the technology is fundamentally different there is no absolute dMax spec; our backs can expose up to one hour, and the normal exposure time required to capture a standard piece of slide film is in the 1/15th of a second range (0.07 seconds; shorter than the blink of an eye). So if you found some exotic material that had incredibly dense, near opaque dMax you might have to increase to, say, eight times as long which would still only be a half second (quite a bit under the one hour maximum exposure time of our system). So the limit is only on range, not absolute value, and so far as I can tell from practical testing this isn't a limit at all.

If anyone has some exotic transmissive material that has unusually large range that would be willing to submit it to our testing we'd love to have the opportunity. We're always looking for new applications for our gear (for obvious self interested sales reasons as well as intellectual curiosity). The other day I tested the system for scanning biological specimen slides (in this case dead monkey brain cross sections) and it beat out a dedicated high-res medical slide scanner that took 30 minutes to complete a scan (and only succeeded to complete the scan without errors about half the time).

[dougpeterson]

I see that you are in Tucson. The Center for Creative Photography at the U of A has one of these systems. I saw it when visiting back in early 2014, so it may be an early version.

Indeed the CCP had our first generation kit (same image quality, slower workflow) at the time.

They recently upgraded to the new/current system.

They are one of my favorite clients. They house the life work of Ansel Adams, Edward Weston and several other larger-than-life names in American photography.

PS to Doug: Tucson is misspelled on the client page of your website.

Not anymore, thanks!

[Alan Klein]

I may have missed it. But are there visual comparisons between this unit and the better drum scanners that we can look at?

[Peter De Smidt]

I agree with Doug regarding dynamic range. Even with an older Nikon Dslr, the dynamic range is at least 1 stop more than an Epson scanner, as measured with a step wedge, and the ability to easily change exposure is a benefit. The Phase One back should be even better. The tremendous advances in camera style sensors is what makes this a viable option. Line sensors haven't seen anywhere near the same development. I doubt, for example, that a sensor in a current Epson scanner is much different from ones from the 1990s.

[dougpeterson]

I may have missed it. But are there visual comparisons between this unit and the better drum scanners that we can look at?

Alan,

I'd be glad to send them to you, but they are several GB of data so hard to post as a public link. Also we've found that anytime we show comparison images to someone they question whether the drum scan was done correctly, or whether the drum scanner was out of calibration, or whether they could have used better settings (all valid concerns of course). I understand that, as I myself rarely trust a comparison done by someone who is interested in the outcome, and in this case it's even harder because the aesthetics of how you want the film grain rendered are a huge component; if we all posted our "ideally sharpened" scans here I'm sure there would be a wide variety of what individuals consider ideal. So it's really more effective for everyone that we do a test scan of your film on our system which you can then compare to whatever system you'd like, with whatever settings you'd like.

I see you're in New Jersey; if you ever get into the city it may be easier for you to come to the city and I'll show you file comparisons, the system itself, and you can bring some film to do a test scan of. You're welcome to email me at dep@digitaltransitions.com

Doug

[timparkin]

Alan,

I'd be glad to send them to you, but they are several GB of data so hard to post as a public link. Also we've found that anytime we show comparison images to someone they question whether the drum scan was done correctly, or whether the drum scanner was out of calibration, or whether they could have used better settings (all valid concerns of course). I understand that, as I myself rarely trust a comparison done by someone who is interested in the outcome, and in this case it's even harder because the aesthetics of how you want the film grain rendered are a huge component; if we all posted our "ideally sharpened" scans here I'm sure there would be a wide variety of what individuals consider ideal. So it's really more effective for everyone that we do a test scan of your film on our system which you can then compare to whatever system you'd like, with whatever settings you'd like.

I see you're in New Jersey; if you ever get into the city it may be easier for you to come to the city and I'll show you file comparisons, the system itself, and you can bring some film to do a test scan of. You're welcome to email me at dep@digitaltransitions.com

Doug

Hi,

I'd be very interested in the comparisons of flare on very dense film like velvia 50. I've noticed that all flatbed scanners have problems with this. I have a particularly problematic 5x4 if you're interested in testing? I can provide a drum scan and flatbed scan for comparison?

Tim