Need to make a 9x12cm film holder myself as my new Epson 4870 scanner comes only with a 4x5inch holder.
This should be an easy task if such a holder just needs to hold the film flat and ensure that glass and slide don't touch each other.
On the other hand things would get a little more complicated if the distance between glass and slide needs to be exactly identical with the 4x5 holder .
Any advice is very welcome.
I've found that the negative (I'm doing 5x7's) can be placed directly on the glass of the 4870 without loss of resolution. The difficulty is a tendency to get newton rings. This can be reduced by placing the negative emusion side down (emulsion side is much less likely to make newton rings because it's less shiny) which just means the file has to flipped after scanning to get it right-side-out. Any attempts I've made to come up with a home-made negative holder have resulted in a storm of dust and more trouble than working right on the glass. A 5x7 holder just like the 4x5 one that came with the scanner would be nice, though.---Carl
I have the Epson 3200, and I have made my own film holders. I used rigid plastic sheets I got at a local hobby shop. They come in various thicknesses, but the 1 mm thickness seemed closest to the ones provided by Epson. One problem is that larger format films can sag, so it is difficult to maintain a uniform height above the glass throughout the frame. But it probably doesn't matter much since the optics have quite a lot of depth of field. Particularly for larger formats, which require less enlargement, the focus is not that critical. As you note, you do wan't to avoid contact with the glass because of the possibility of Newton's rings. If you do put the film directly on the glass, you should probably put it emulsion side down and then reverse the orientation in the software.
Positioning the film exactly over the hole can be difficult, so it is a good idea to cement some guides to the holder to help with that.
I used an Exacto knife and a metal straightedge to cut the holes. It requires a bit of practice to get straight cuts just where you want them. Usually you need to cut more than once to get through the material.
Thick rigid cardboard will also work, but it may not be as permanent.
Some people have suggested using magnetic sheets. I made one for 6 x 7, but I don't find it convenient to use.
I agree that the optical system of the Epson 4870 has a lot of depth of field and that one can get good results at distances other than the 0.032" (about 0.8 mm) of the film holders. However, I have checked sharpness with my 4870 with the negative on the glass (emulsion side down), and at 0.032" (base down) and at 0.064" (base down) and found that I get slightly sharper results at 0.064". By contrast I remember that my Epson 2450 gave better results with the negative on the glass.
What I am using now as the film holder for 5X7 film is a piece of phenolic plastic of 0.064" thickness shaped to the outside dimensions of the other 4870 holders, with a cut-out for the 5X7 film. To use I place the film over the opening, tape it down on one end, then put a piece of tape on the film at the other end and pull it taunt. This puts tension on the film and keeps it elevated above the glass.
For discussion and information about carbon transfer please visit the carbon group at groups.io
[url]https://groups.io/g/carbon
I was told a For Sale sign from the hardware store was the perfect thickness. But have not tried it.
HI, I cut 2 mats from 4 ply black mat board with the proper size hole and use a little tape to hold the transparency to the bottom board. I just bought an Artixscan 1800 and plan to mat all my 8x10 transparencies for scanning..Evan Clarke
Regarding the variation of the focus point, there is
this
note about the 2450/3200, which outlines a procedure one could apply to the
4870 as well. There seem to be some variability with the 4870, since at 1.5mm, unlike Sandy, I
got scans that were significantly softer than on the glass. I use a piece of matboard
and tape the film on opposite edges too.
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