I may be wrong, but negatives are not supposed to be touching the glass on the Epson 4990. That's one of the reasons for the Epson holders.
To that end, Doug Fisher has created an entire series of holders that can be adjusted to achieve best focus, since there is some variability among individual scanners.
See www.BetterScanning.com for what he calls the Variable Height Mounting Station.
The "before and after" example shown here, may strike a familiar chord.
Sigh, please understand people that we are NOT talking about a global focusing issue, rather this is a problem with specific parts of an image. The relative levels of sharpness between the 'good' and 'bad' areas are constant through all the different shenanigans I've put this neg through as detailed on the previous page. I may still buy Doug's product, he has a good reputation, I don't think however that it is relevant to this discussion.
Ben, you might need to waste one Polaroid sheet. Pull the packet and see if the film is flat. When I first started in LF I made a mistake of buying an early Kodak Readyload holder and using it with Quickloads. I had similar problems to you. I wasted a sheet, but it showed me I had a horrendous ripple in the film. The holder went in the bin. The 545i I use with Readyloads holds the film flat, as does the Quickload holder with Quickloads. Sounds as if the film is either not flat in the film holder or scanner, but you've isolated the scanner.
Sounds like a mechanical/optical defect in the scanner. Try a new one...
I have my next sheet drying, I'll tell you how it worked out when I get a second to scan it.
To make things certain I now have neg sandwitched between two hardback books with another ten books on top. Want to make sure it's not my technique at fault!
Ben, my guess is that the film is "popping" during the scan due to the heat of the lamp. I had the same problem repeatedly with my Epson 2450; rather than OOF areas, I usually saw Newton's rings because the film would buckle downward and touch the scanner glass. My solution was to use Scotch tape to fix the narrow ends of the film to the Epson holder. One piece of tape about an inch long at the film end nearest the middle of the holder, then put a second piece of tape on the other end of the film and apply slight tension before sticking it down to the holder. I haven't had Newton's rings since. Perhaps this would address your problem; it won't cost anything to try.
It may be relevant after all.Originally Posted by Ben R
With proper holders, a negative is held not only at the point of best focus, but is also held flat. With Doug's large format holder for the Epson, the negative is taped to a piece of anti Newton's Ring glass, and is then held at the ideal distance above the scanner glass. The ANR glass is positioned above the negative, helping to block heat from reaching the film, from the lamp above. Blocking the heat, also helps to keep the negative flat. When the negative is flat, we don't see regions of varying focus.
According to that though Ken when I taped it flat against the scanner glass the focus should have been uniform for all that it would not have been optimal.
I see what you mean. True enough !
How about scanning the same negative you have already shown us - but move it or change its orientation. Make sure that the "blurry" sections of the negative are now above a different region of the scanner glass. If the same parts of the negative are coming out blurry in subsequent scans, then it's your negative.
Otherwise, it's probably best to get the Polaroid out of the equation, especially if it is difficult to tell under a loupe, whether the blur is on the film.
You might want to make your own "scanning target": Take a blank sheet of transparent plastic, and draw grid lines on it with a pen. If when you scan it, all the lines are rendered equally, then the scanner is OK. See if the scan quality varies, depending on the region of the scanner glass.
Have you tried scanning a reflective target - like a printed page from a magazine, or a dollar bill ? If even a reflective target ends up with a blurry image - according to a consistent pattern - then you know that the scanner is faulty.
For all we know, the scanner was damaged in transit, perhaps by a delivery service that gave it less care than it deserved.
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