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Wet mount scanning

squeezing the last drop out

in Film , Wednesday, February 16, 2011

Back in October, a blog post by Ctein on The Online Photographer first alerted me to existence of 3rd party fluid mounting kits for many scanners.  Specifically, he mentioned ScanScience‘s kits, based on their Lumina fluid.

I was intrigued enough to check this out, and eventually ordered a kit usable on my Minolta Dimage Scan MultiPro from ScanScience. Since they are in Canada, and the fluid cannot be carried by air, it takes quite a while to arrive, and it’s also better to order a reasonably generous supply.  So there’s quite an element of flying blind here, but my feeling was, well Ctein knows what he’s talking about, what the hell.

Anyway, it arrived a few days ago, and I started playing around with it. Precision scanning is both fiddly and something of a black art. My initial impression of fluid mounting is that it certainly increases fiddlyness, and also adds several more ways in which you can screw up a scan ... or indeed a scanner, in the worst case scenario.

My initial attempts were not too successful, and I had to dismantle a 6x9 glassless holder to fit the fluid mount assembly as recommended. But after a few tries I started to get the hang of it. The main challenges are getting the right amount of fluid onto the various surfaces, and avoiding dust and dirt contamination.

The basic idea with fluid mounting is to keep the film flat, and to avoid optical path degradation which arises from various factors in dry scanning - I won’t repeat the explanations here, you can find them at ScanScience and various other resources.

The following images show the best result I’ve obtained so far. Comparing a couple of sections of a 4800dpi XPan scan of Ektachrome E100G, wet mounted and dry mounted, shows some advantage, at 100% magnification, for wet mounting.

PhotoshopScreenSnapz001

PhotoshopScreenSnapz002

At the top you can see the wet mount version on the left, dry mount on the right [CORRECTED!]. Colour differences are down to slightly different settings in Silverfast HDR - ignore these. The images have suffered a little in JPG compression, but looking at the rightmost telegraph post, and the background forest, you can see a touch more resolution. But it’s not exactly jaw-dropping.

The next example is a bit more convincing:

PhotoshopScreenSnapz003
PhotoshopScreenSnapz005

Here, the lower scan is wet mounted.  Certainly there is a touch more resolution here. Or maybe I focussed better… who knows ?

ScanScience claim a number of things, including:

- Better edge to edge sharpness: hmm. Probably, but with the “sandwich” mounting technique I’ve evolved over the years, and the relatively deep depth of field of the Minolta, I’m not - so far - seeing any benefit.

- Better contrast and detail: as shown above, yes, but we’re splitting hairs, to be honest.

- Extended dynamic range and saturation: Nope. Well, not for E6 slide film, at least. The Minolta covers the range of E100G and other low(er) contrast films quite happily, and has no issue at all with higher contrast.  However, this benefit may apply more to negative colour and black & white. I’ve yet to try this.

Hides dust & scratches: no. Absolutely not. If anything it makes things worse due to more places for dust to get in, and if dust gets into a fluid layer, it’s pretty much game over, time to remount.

So, in summary, I’m seeing minor improvements which don’t really appear to justify the cost and time.  But it’s not quite as simple as that. First of all, one thing is clear: to get any benefit at all, the image has be well exposed and sharp. Secondly, it seems that the benefits are more towards negative and larger formats.

There’s actually a lot of discussion out there on the interwebs about wet mount scanning, and by & large I’d say the overall impression is of mixed results. In particular, this discussion thread confirms my findings. Pity I didn’t do a bit more research…

At the moment I would tend more to reserving it only for “top picks”, but it’s early days yet.