Moire Pattern on Epson 4990 scans

[Bob Parker]

Hello,
I am new to this board and new to scanning film negatives. I have an Epson 4990 Pro and am using Silverfaast AI Studio as my software. I have scanned about 20 6x12cm Noblex 150 panoramic negatives previously with this scanner and Silverfast, with what seems to be excellent results. Today however, I notice that my 6x12 negative scans show a moire pattern in the dark brick of the building I photographed in the negative. I am using the manufacturer supplied negative holder. I do not think this moire has shown up in the other negatives I scanned, and this is confusing to me. Can anyone give me advice on how to deal with this problem? Is it a scanner problem, can it be fixed in Photoshop? Thanks in advance for all responses. If I find out any additional info outside of the board, I will post what I find.

Bob Parker

[Ed K.]

Hi Bob,
A couple of questions:

1. When you look at the "actual pixels" in Photoshop ( 100% magnification ), does the pattern go away? If so, then the scan itself is good, you just need to resample if you want it for web size
( monitor resolution ). If you have something very sharp and then look at it at reduced size on your monitor, patterns can show up that are due to the frequency of the monitor pixels vs. the image content. If you're really lucky, you may have a pattern that actually does produce moire with the resolution of scanning you have selected. What res?

2. Sure that it is moire and not the neg sagging down from the holder, touching the glass for a newton ring effect?

3. If not the above, try changing the res and sharpening settings, but best of all maybe you might post a sample of it on the site here, at 100% for the affected area so that everyone can see what you're talking about. Then suggestions might be better...

[Leonard Evens]

Sometimes you see a moire pattern as a result of interference between a pattern in the image with characteristics of the display. Photshop is usually pretty good at avoiding that, but in some cases it may still crop up. A clue that this is your problem is that it disappears on higher magnification.

[Kirk Gittings]

" is moire and not the neg sagging down from the holder, touching the glass for a newton ring effect?"

That would be my guess. Leave it in a book overnight to flatten it, then scan it curve up. Epson says not to that way but I do it 40-50 times a week and it works fine on curly color negs.