epson 4990 focal plane help

[mervynyan]

I just got few rolls of mounted 35mm slides back, it is first time I had them mounted. I placed the slides directly on the glass and fixed the position using 6x6 holder, they fit alright but it seems the slides can't be focused properly. it is no comparison with the viewing on light box. Even though I understand the focal plane is not 100% correct, but when I scan other unmounted slide strips using 35mm holder, the photos look sharper on screen.

I was thinking unmounted all slides and wasted all the paper clips, then mount back again. just seem very complicated.

Is there any work around? I need some expertly help here.

Cheers,
Mervyn

 

[wintoid]

I thought the 4990 came with a 35mm slide holder...

 

[xvvvz]

With the 4990, the *mounted* slides are not supposed to sit in a holder. It comes with what looks like a holder but it is really more like mask that fits around the outside edges of the mount but don't actually hold/suspend it. This due to the theory that a mounted slide is (hopefully) going to actually suspend the film about 1 mm off the glass. If you put a mounted slide into a film holder, the holder will raise the mount by 1 mm plus then the mount raises the film further. Theoretically, you are now at 2 mm. Often this will make the scanned image unsharp. There are lots of words like "supposed" and "theoretically" in this post because slide mounts may or may not suspend film at 1 mm, there may be film curl in the mount which adds another variable, and/or your 4990 may or may not actually have an optimal focus point at 1 mm (which is what Alex was talking about in his post).

If you have lost your slide mask, use your 35 mm film strip holder as a template for the outside shape and create a mask out of black material. Then cut apertures in the center just large enough to fit slide mounts.

Doug
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www.BetterScanning.com