Thin Glass Sheets

[Lawrence Francis]

I'm looking for a source of thin plate/sheet glass. Something as big as 8x10 to as small as 4x5. With regards to thickness; 0.100" (2.5mm) or as close as I can get to it.

Stephen Shuart use to carry a line of Jena Glass Products, but I think he is out of business, I can't find his website.

I'm using this to keep my large format negatives flat & in focus on my flatbed scanner.

Any suggestions...Thanks

[Michael S. Briggs]

S. I. Howard Glass lists a wide range of thicknesses of several types of glass: http://www.howardglass.com/. I have never purchased from them. Focal Point might have something suitable: http://www.fpointinc.com/web_store/Products/focal/prodindx.htm.

[Joe Hunt]

Regarding using glass under/over the negative on flat bed scanner, can anyone clarify this for me:

Flat bed scanner neg holders (of the Canoscan w. filmholder variety) hold the negative higher than a print on the platen. Is the filmholder the ideal focus position for film scanning or is it just inevitable (and not desirable) that the neg will be held at that height?

If replacing the plastic neg holder with a sheet glass, should I place the neg on the platen glass (with a thin sheet on top of neg) or raise the neg to match the depth of the supplied plastic neg holder?

Surely there's a focus/depth of field issue here. I'm wondering if depth of field of a short focus scanner lens allows the varying heights, or whether there is an optimum height, such as on the platen.

If the platen is the best position I could make up suitable masks for differing formats.

Or have I wrong assumptions on flatbed scanner optics? Best wishes

[Lawrence Francis]

Michael: Thanks for the lead, their (S I Howard) website is loaded with possibilities.

Joe: You are looking at the same situation I am. Surely some plane on/above the platen glass is "THE" best place to be for optimum focus. My Epson 2450 neg carrier is 0.040" thick. Negs scanned in their holder are terribly out of focus. There not even held flat! Scans with the neg directly on the flatbed glass are not much better. I'm going to try neg scans on the platen; and then every 0.020" above it till I get to 0.100". Out of those six planes, one of them will be the correct place.

Well..I hops so anyway!

[Ernest Purdum]

I have just noticed that several sizes and thicknesses of glass sheet are available from Surplus Shed (www.surplusshed.com). Check out the optical windows category.