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5×7 film scanning hacks

edgeshadows

Mystery shadows with Epson V700, parallel lines on right vertical edge of frame
(enlarged and contrast boosted for clarity)

I went though some embarrassing fits of misdirection trying to track down the cause of these odd parallel shadow lines of less density around the negative’s rebate edge. First I thought that it was an artifact of slosher tray development- due mostly to the tendency of film to curl along its length, thus leaving a edge of the film that would stick out of the developer and receive less development due to the meniscus effect. But the artifact was still there when I began to develop film in a Jobo drum, which spins the film in individual tubes through the solution constantly during processing. At that point I was convinced it was caused by using excessive movement of the front standard of my camera when composing a photograph, which then would cause an off-axis shadow from the back aperture to be cast along the corresponding edge of the film. So I beveled the edge of the back aperture to make this impossible. When that didn’t work I stained all the margins of my film holders flat black to make sure they weren’t causing some odd light scatter. When that didn’t work I finally looked at my scan procedure itself.

I scan 5×7 negatives on a V700 by taping the negative to the bottom of a piece of ordinary window glass, which is supported in the corners by 4mm thick bumpers. No mask or frame is used- 5×7 is a size that isn’t supported much with peripheral accessories, no negative carriers for this film size came with either my Microtek M1 or Epson V700. With the M1 I made a custom film drawer for ‘odd’ sizes like 4×10, 5×12 and 5×7. This worked well when the auto-focus of the M1 decided to cooperate. With I abandoned the M1 and got the Epson, I experimented to find the sweet spot of the scanner’s lens, then suspended the negative in that plane. Putting the film on the bottom of the glass reduced newton rings, and is one less surface for dust to collect on or for information to pass through, etc. And I made many happy scans this way until the shadows starting showing up.

This lapse I can’t explain- this simply wasn’t an issue for the first several hundred scans on the Epson. Then they were there, always along the edges of any light-density field such as skies. This corresponded roughly to the new 5×7 camera build, so I thought the too-crowded back opening or film holder reflection was likely the problem- but it was essentially the same as the last camera I had, so looked to rule out development first. After ruling out all else, I finally thought to try masking off the negative’s clear margins to insure that no odd shadows or refelctions were being caused by the scanner lamp. Sure enough that did it. So I taped a permanent boundary for the negative out of rubylith on the top of the glass (so the thickness of the tape doesn’t throw the negative¬† out of the focal plane) then align the film to the rubylith boundary on the light box. The downside is this crops off the film rebate around the image, but I’ve always thought that the black uncropped edge in images was a bit too dutiful anyway, like proof or validation of the format you use. It has always reminded me of the butcher’s tradition of leaving the un-skinned feet and tail on a dressed rabbit carcass, to prove that you aren’t actually selling some feral cat counterfeit instead.

ruby

Cheap low-tech fix. Plain 1/16″ glass with corner bumpers. The negative is taped to the glass with low-tack drafting tape, which is reusable for a half-dozen scans or so, and is sticky enough to stretch the negative taut, but not sticky enough to leave any residue on the negatives. 5″x7″ film size is permanently masked off on opposite side of glass from negative with Rubylith tape. The assembly as shown above is flipped onto scanner bed so that negative is on the bottom of glass, facing the scanner’s optics. The 4mm thickness of the rubber feet was blind luck- they perfectly position the negative at the factory-set focal plane of the V700’s lens.

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