How to keep negative sheets flat on Epson 13000XL scanner?

[narikin]

Maybe somebody else has come across this issue, but I purchased a 13000 XL so I could scan 40 years archive of film photography from my negative file sheets.

I have been simply putting the (transparent polyester) file sheets, holding my MF and 35 mm negatives, but... they lift up at one end, reducing the top to bottom height of that sheet, and giving a warped non-square scan.

Other than taking every single negative strip out and putting them in the film holder, then back again, (which I may well end doing!) is there some sort of sheet I could put on top to flatten? It would need to be anti-newton glass to avoid those rings, I guess, and not frosted or that would be scanned as a sandy detail in the images.

Any suggestions how best to do this ?

[Richard.Wills]

If you are using the scanner to make functional contact sheets, then try regular 3mm low ion glass, but run strips of camera tape around the edge, to reduce the pressure. One or two passes can be enough, and the tape helps prevent the glass from scratching the scanner glass. You may still get rings at the edges, but it'll work as well as a darkroom contact with an 8x loupe