The Scanner

Minolta’s Dimage Scan Multi Pro film scanner is a wonderful bit of kit for the digital darkroom offering some of the best performance for film scanning of any desktop film scanner. One of it’s key advantages is that it is capable of making scans the width of 35mm at 4800dpi for 9cm as a result of it’s medium format capability. This has meant that it ought to be the best solution available for scanning images taken on 35mm panoramic cameras that deliver wider than normal frames. Cameras like the Noblex 135 series and Hasselblad X Pan cameras both deliver frames 65mm long, wider than virtually any 35mm scanner can handle as standard.

It looked ideal for us panoramic enthusiasts.

The Problem

Whilst the Scan Multi Pro is capable of scanning the area of a 35mm panoramic negative at 4800 dpi in one pass the only provision for holding that negative in the scanner as provided is the medium format glass carrier.

This carrier has three problems when in use for scanning 35mm panoramic negatives.

Firstly, it is difficult to place the film centrally on the glass, meaning time consuming work levelling the image in software at a later stage.

Secondly, using the glass carrier there are three times as many surfaces that collect dust. This makes far more work for the dust removal function of the driver’s software and often seems to leave unwanted artefacts in the final image. When scanning some films, e.g. black and white silver based films, the option of automatic dust removal in software isn’t available anyway.

Finally, if unlucky through environmental humidity, Newton’s rings patterning can become a serious problem.

Minolta do make a "Multi format set" for scanning unusual format film, but it is reported to be awkward to use and still has the drawback of still using glass to keep the film flat. It uses the same medium format carrier that is supplied with the scanner, but the kit includes an additional insert for multi format use. It’s also very expensive.

What’s needed is a glassless carrier just for panoramic film.

The Plan

Courtesy of someone on the Multipro users list I discovered that it was possible to buy spare 35mm film carriers for a modest amount(£35 in the UK) as spare parts from Minolta. I resolved to get one and attempt to modify it to use for scanning my panoramic films.

Having used the scanner a while it was apparent that it wasn’t possible to "over scan" the supplied glassless carrier, so simply removing a separating bar wouldn’t be enough to make a glassless carrier. The scanner was sensing which carrier was fitted and only allowing certain areas to be scanned dependant on the carrier inserted.

I started off by carefully studying all three of the supplied negative carriers and the scanner itself. It became apparent that the scanner was detecting the carrier and positioning it with the use of two optical sensors. These are fitted on the right hand side of the scanning area as you look into the scanner through the front carrier door. They look at a moulded strip that runs along the base of the carrier that has different lengths and cut outs on each of the supplied carriers.
Some of the functions of the moulding were immediately clear. At front end it just gets the scanner to start driving the carrier into the scanner, the other end acts as limit for the scanning area. Quite what the cut outs in between those limits do is harder to understand.
There are also a number of other cut outs on the medium format carrier that differ from the 35mm carriers, but there seemed to be no switches or sensors that could detect them so I hoped they weren’t significant and ignored them.

After much thought and consideration it seemed that the best plan would be to try to modify the new carrier so that the scanner would detect it as a medium format carrier and allow 4800 dpi scanning of just one area.
To prevent possible damage by the carrier being driven in too far I decided it best to remove the separating bar between frames 4 and 5 on the carrier and scan just that area. Following on from that decision I chose to reduce the length of the moulding so that the frame 6 side of frame 5 would be the limit of the scanning range. Then match the cut outs from the medium format carrier from the new end limit at frame 5
At this point another issue raises it’s head. I normally cut films shot with panoramic cameras into strips of three frames so that they fit into standard filing sheets. To scan each frame within the new opening it would mean having to move the film beyond the end stops moulded on the carrier, so that became another couple of bits to remove as well.

The Risks

Modifying parts to make equipment do something it wasn’t designed to will always carry a risk. It is possible that the modified part may not work as expected and may damage the equipment and wouldn’t be covered by it’s warranty.
In this case it may be that modification of the film carrier would cause the scanner to drive the modified carrier too far into the scanner and damage the interior. An expensive concern.

The Graft

Having finished the hard part of the conversion, deciding what to actually modify, I just had to engineer the modifications I thought necessary.

The first part was relatively simple. The dividing bar between frames 4 and 5 of the carrier was careful sawn out with a very fine toothed saw close to the edge of the carrier. The stumps left where then carefully filed down until flush with the existing frame edges using progressively finer files and finally finishing off with 600 grade wet and dry abrasive paper. Care was taken to ensure no rough edges were left at any of the places material was removed throughout the modification.

The second thing to deal with were the end stops of the film carrier. I started by starting to remove most of the material with a sharp craft knife, but stopped just before the base level of the carrier. The final material was removed using a small end cutting bit* mounted in a drill press to mill the base flat. When flush the area was finished with 600 grade wet and dry abrasive paper to ensure there were no sharp edges to damage the film surface.

Next I turned my attention to modifying the moulded rib under the carrier.
The hardest part was to fill the two cut outs that were superfluous. To do this I used a very fine drill bit(1mm? possibly less) in the drill press again and cut several small holes in the base of the cut out and very carefully used the drill as a mill to make the individual holes into a slot aligned with the existing rib. I then cut a small piece of styrene sheet the same thickness* as the moulded rib to fit into the new slot and project up to fill the cut out with a small amount projecting that can be filed down to match. It needs to be a tight fit, but no wider than the existing rib, then cemented in with a styrene solvent such as Methyl Ethyl Ketone* applied with a fine brush. With care this should become a very strong bond, but needs to left for some time to completely harden. When set hard, the top surface was carefully filed and abraded to the be completely flush with the top surface of the rail. To prevent any problems with the light sensors in the scanner "seeing through" the white styrene sheet I painted them with matt black enamel paint*

The final part of the conversion was removing excess parts of the rib no longer needed. I started by removing all of the rib beyond the end of frame 5 to limit the carrier’s travel and then cut four notches in the rib to match the medium format carrier’s rib. Most of the material was roughly removed with a sharp craft knife and the bases were levelled using the fine end cutting drill bit in the drill press again.

Once everything was finished everything was very carefully inspected for any rough edges and finished with 600 grade wet and dry abrasive paper. Then the entire carrier was cleaned very carefully with a soft brush to remove any dust or abrasive particles and finally blown over with compressed air.

The end result

When finished I booted up the scanner and fed the modified carrier in. It went straight in without any problems or odd noises and works perfectly. The film seems to be held flat enough not to detect any unsharpness in the image. This was expected as medium format glassless carrier seem to perform perfectly acceptably and with the narrower width of the 35mm film it ought to be held more securely anyway.
It is seen by both Minolta’s own driver software(ver 1.0.2) and Ed Hamrick’s excellent Vuescan program ( ver 7.5.45) as a medium format carrier without problems.

A Final word

Now maybe Minolta could offer something like this. It might even be possible to have the scanner move the carrier from frame to frame too, which make life even easier. However I think the market is probably too small for them to make that investment. It would have been nice if Minolta had replied to my emails asking for assistance in making this conversion, but hopefully they've been too busy upgrading their driver software to have the time to help me. If anyone from Minolta does come across this page, please let me know what you think of what I've done.

Notes