New article by Leigh Perry: Collaborative scanner comparison

[DYMERSKY MICHAEL]

How long until the Microtek ArtixScan 1800F will be added ?

[Matthew Cromer]

For those who don't want to wait on the 4990 comparison,

Quentin Bargate has a pretty impressive comparison linked from the boards at photo i:

Comparison of Howtek Drum scan and Epson 4990 @ 2400 DPI

[Leigh Perry]

The additional scans will occur over the coming weeks and months.

The Epson 4870 is happening in Canada right now. The transparency will come back to me me here in Sydney for an Epson 4990 that I've organised, then off to Cairns for the Crosfield drum scanner and Fuji Lanovia C550 flatbed. The remaining scans are in the UK and USA.

Where possible, I ask the volunteer to just sent the film to the next volunteer, but it still takes at least two weeks per scan because of airmail times and operator availability.

[Edwin B.]

I’d say that’s a commendable effort and an interesting comparison. However, a few limitations of such a comparison should be pointed out at least with respect to the drum scanners. It is often claimed that for drum scans the operator is more important than the brand and for the more recent models I think there is a lot of truth to this. The first drum scan I saw was done several years ago by a well regarded pro lab using a Howtek 4500 and the results were less than exceptional with tons of noise and artifacts. I complained and was told that the original was grainy and that it was as good as it gets. Fast forward a few years and I own the same model and couldn’t be happier with the hardware. After a lot of late nights of fiddling around (about six months worth) I rescanned the same original with far better results. In the process I learned a thing or two about scanning.

With respect to sharpness the scanner’s focus is critical and the automatic setting may not be good enough. This may be where the difference between the tango and the others arises. With the Howtek I have to use manual adjustments for critical focus in which case the grain structure is clearly visible especially in the case of a film like Velvia 50. At 4000dpi the Howtek is generally capable of resolving finer detail than most real-world large-format film images contain. If the unsharpened scan is fuzzy at 2000dpi and the original is critically sharp the scanner is probably not the problem.

Other explanations are possible. The scanning resolution is not very meaningful without also controlling for aperture. The aperture really determines the resolution of the image signal (the area of the image that is viewed by the scanner at any given time) and the scanning resolution then determines the rate at which that signal is sampled. Thus, a scan with a relatively large physical aperture and a high scanning resolution results in an over-sampled lower resolution image. On the other hand, a scan with a relatively small physical aperture and low scanning resolution results in under-sampling with aliasing and a noisy image. Both parameters need to be controlled or statements like “scanned at X dpi” can be misleading. I won’t even begin to go into the issues arising from resampling all of the scans from optical resolutions to 2400 dpi.

Shadow detail is more difficult to deal with and controlling for white point and black point is a start but the slope of the analog-digital converter’s gain curve near the black point is also critical. In this respect each of the scanners is probably setup differently at the hardware level and most software packages provide (unfortunately) very limited direct control over the A/D converter.

What this all means is that comparing drum scanners is really an exercise in comparing a nebulous combination of software, hardware settings, and operator decisions and probably doesn’t really indicate a whole lot about the particular instruments’ capabilities. However, these sorts of comparisons are useful to the extent that they represent the quality of results that an average user or customer is likely to realize. It’s just never clear how representative a particular scan is.

[tim atherton]

if you are itnerested I can do a Umax Powlerlook III in Canada - an oldie but still a goodie

[Leigh Perry]

Tim, I've emailed you at your kairosphoto address to coordinate the scan.

[Nghi Hoang]

This is great stuff! Thank you!

[Jeremy_D]

Where you had to interpolate up, what method was used?

[John Hennessy]

Leigh,

This is a great idea. The Epson 3200 results were discouraging to me because I have one. I notice many who use a scanner such as an Epson probably do not use its own program to drive it. I use Silverfast AI as do many others. For some elements of your test, e.g., noise in shadows, Silverfast may make a difference. Also, I would bet that Epson scanners are not subject to much quality control so one may be far worse than the next. At 350 usd, Epson is not going to cull very many out.

So, I am volunteering to be included in your loop to test my 3200 with Silverfast to see how it compares to the other 3200 you have already tested.

[Gary Barnett]

Great, long overdue comparison!! I would love to see other prosumer models included also, such as the medium format Coolscan 9000, given the unusual feature of multiple scans to reduce noise.

I own the Imacon Flextight II, and the noise I see in the dark areas is all too disturbingly familiar...if I'd had this comparison available to me at the time of purchase I think I would have tried for one of the drum scanners instead, especially because my Imacon "loses" ppi as the film size increases, and I also shoot 8x10, a size it does not handle at all... oh well. I've gotten my money's worth out of it in scanning well exposed film!

A note to other Imacon owners: if you are scanning color negs, I once had a tech on the phone with me for about an hour (he was let go, unfortunately) and learned that one should use a NEGATIVE number (-60 was suggested) in the USM window, to reduce film grain and general noise. He also suggested a +152 USM setting for chromes, using a 4 grain limit in both cases.

I haven't found a lot of use for their proprietary noise reduction feature yet...it seems to do as much damage as help in most cases, so I prefer to use selective USM in Photoshop for the final image.

Anyone want to sell me an Optronics? I should mention I am broke, but would gladly trade in my Imacon, which is in perfect condition with spare bulbs still in original packaging. These bulbs never seem to quit!