Minimizing Moire patterns when scanning large format negat..

In article <kLccg.87426$TK1.68135@fed1read06>,
Terry Smith <TMSmith.TakeThisOut@abriget.com> wrote:
>I'm a large format photographer using an Epson 4870 scanner to scan my 5x7
>negatives. I've had a custom 5x7 carrier made to hold the negatives (similar
>to the 4x5 transparency carrier that came with the scanner). In general,
>this setup work quite well, but I'm getting moiré patterns, especially in

Those aren't "moire patterns", they're Newton's rings. They're caused by
interference between re-reflections of the image across the airspace between
an imperfectly flat negative and an imperfectly flat piece of glass (both
of which are more or less inevitable).

If you dare, the most effective way to address these when scanning is to
coat the negative with special oil. Then you'll just have to clean it --
and your scanner -- before you use it for anything else...

Oil immersion is still standard practice when doing high-resolution drum
scans, I believe.

--
Thor Lancelot Simon tls.TakeThisOut@rek.tjls.com

"We cannot usually in social life pursue a single value or a single moral
aim, untroubled by the need to compromise with others." - H.L.A. Hart
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

tls RemoveThis @panix.com (Thor Lancelot Simon) writes:
> If you dare, the most effective way to address these when scanning is to
> coat the negative with special oil. Then you'll just have to clean it --
> and your scanner -- before you use it for anything else...

There's special glass mounts you can get that avoids it somehow, at
least for 35mm slides, I dunno about large format. Look for
"Anti-Newton" glass.
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

"Terry Smith" <TMSmith.DeleteThis@abriget.com> wrote:
> I'm a large format photographer using an Epson 4870 scanner to scan my 5x7
> negatives. I've had a custom 5x7 carrier made to hold the negatives
> (similar to the 4x5 transparency carrier that came with the scanner). In
> general, this setup work quite well, but I'm getting moiré patterns,
> especially in the middle of the negatives where there is a lot of single
> tonality area (like open sky) mostly on B&W negatives.
>
> Does anyone have a clue on how to minimize this moiré pattern problem?
> (and no, I'd rather not send my negs out to be drum scanned... <s>)

Are you sure it's not Newton's rings? Is the film touching the glass? My
experience with the 2450 was that Newton's rings was a nasty problem, but
the 4800 ppi Epson scans I've seen would lead me to doubt that Moiré would
be an issue.

David J. Littleboy
Tokyo, Japan
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

David, Thanks for the correction. I'm sure they are Newton's rings; I don't
know why I called them Moiré patterns...


"David J. Littleboy" <davidjl RemoveThis @gol.com> wrote in message
news:e4rncv$c10$1@nnrp.gol.com...
>
> "Terry Smith" <TMSmith RemoveThis @abriget.com> wrote:
>> I'm a large format photographer using an Epson 4870 scanner to scan my
>> 5x7 negatives. I've had a custom 5x7 carrier made to hold the negatives
>> (similar to the 4x5 transparency carrier that came with the scanner). In
>> general, this setup work quite well, but I'm getting moiré patterns,
>> especially in the middle of the negatives where there is a lot of single
>> tonality area (like open sky) mostly on B&W negatives.
>>
>> Does anyone have a clue on how to minimize this moiré pattern problem?
>> (and no, I'd rather not send my negs out to be drum scanned... <s>)
>
> Are you sure it's not Newton's rings? Is the film touching the glass? My
> experience with the 2450 was that Newton's rings was a nasty problem, but
> the 4800 ppi Epson scans I've seen would lead me to doubt that Moiré would
> be an issue.
>
> David J. Littleboy
> Tokyo, Japan
>
>
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

In article <e4rncv$c10$1@nnrp.gol.com>,
"David J. Littleboy" <davidjl.TakeThisOut@gol.com> wrote:

> "Terry Smith" <TMSmith.TakeThisOut@abriget.com> wrote:
> > I'm a large format photographer using an Epson 4870 scanner to scan my 5x7
> > negatives. I've had a custom 5x7 carrier made to hold the negatives
> > (similar to the 4x5 transparency carrier that came with the scanner). In
> > general, this setup work quite well, but I'm getting moiré patterns,
> > especially in the middle of the negatives where there is a lot of single
> > tonality area (like open sky) mostly on B&W negatives.
> >
> > Does anyone have a clue on how to minimize this moiré pattern problem?
> > (and no, I'd rather not send my negs out to be drum scanned... <s>)
>
> Are you sure it's not Newton's rings? Is the film touching the glass? My
> experience with the 2450 was that Newton's rings was a nasty problem, but
> the 4800 ppi Epson scans I've seen would lead me to doubt that Moiré would
> be an issue.
>
> David J. Littleboy
> Tokyo, Japan

Flipping the original and scanning from the emulsion side does wonders
with the 2450.
--
The sometimes insomniac.

www.gregblankphoto.com
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

"Terry Smith" <TMSmith RemoveThis @abriget.com> wrote in message
news:kLccg.87426$TK1.68135@fed1read06...
> I'm a large format photographer using an Epson 4870 scanner to scan my 5x7
> negatives. I've had a custom 5x7 carrier made to hold the negatives
> (similar to the 4x5 transparency carrier that came with the scanner). In
> general, this setup work quite well, but I'm getting moiré patterns,
> especially in the middle of the negatives where there is a lot of single
> tonality area (like open sky) mostly on B&W negatives.
>
> Does anyone have a clue on how to minimize this moiré pattern problem?
> (and no, I'd rather not send my negs out to be drum scanned... <s>)

Try scanning the negs with emulsion to the glass, then flip the image in
software.
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

How do I keep the negative flat on the glass?


"rm" <rm@hotmailDOTcom> wrote in message
news:4471ad3c$0$25133$afc38c87@news.optusnet.com.au...
>
> "Terry Smith" <TMSmith.RemoveThis@abriget.com> wrote in message
> news:kLccg.87426$TK1.68135@fed1read06...
>> I'm a large format photographer using an Epson 4870 scanner to scan my
>> 5x7 negatives. I've had a custom 5x7 carrier made to hold the negatives
>> (similar to the 4x5 transparency carrier that came with the scanner). In
>> general, this setup work quite well, but I'm getting moiré patterns,
>> especially in the middle of the negatives where there is a lot of single
>> tonality area (like open sky) mostly on B&W negatives.
>>
>> Does anyone have a clue on how to minimize this moiré pattern problem?
>> (and no, I'd rather not send my negs out to be drum scanned... <s>)
>
> Try scanning the negs with emulsion to the glass, then flip the image in
> software.
>
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

In article <qNlcg.87432$TK1.42357@fed1read06>,
"Terry Smith" <TMSmith.TakeThisOut@abriget.com> wrote:

> How do I keep the negative flat on the glass?
>
>
> "rm" <rm@hotmailDOTcom> wrote in message
> news:4471ad3c$0$25133$afc38c87@news.optusnet.com.au...
> >
> > "Terry Smith" <TMSmith.TakeThisOut@abriget.com> wrote in message
> > news:kLccg.87426$TK1.68135@fed1read06...
> >> I'm a large format photographer using an Epson 4870 scanner to scan my
> >> 5x7 negatives. I've had a custom 5x7 carrier made to hold the negatives
> >> (similar to the 4x5 transparency carrier that came with the scanner). In
> >> general, this setup work quite well, but I'm getting moiré patterns,
> >> especially in the middle of the negatives where there is a lot of single
> >> tonality area (like open sky) mostly on B&W negatives.
> >>
> >> Does anyone have a clue on how to minimize this moiré pattern problem?
> >> (and no, I'd rather not send my negs out to be drum scanned... <s>)
> >
> > Try scanning the negs with emulsion to the glass, then flip the image in
> > software.
> >

The idea is not to have the original flat on the glass....the reason for
the Newton rings is somewhere the original is touching the glass.
--
The sometimes insomniac.

www.gregblankphoto.com
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

> I'm a large format photographer using an Epson 4870 scanner to scan my 5x7
> negatives. I've had a custom 5x7 carrier made to hold the negatives
> (similar to the 4x5 transparency carrier that came with the scanner). In
> general, this setup work quite well, but I'm getting moiré patterns,
> especially in the middle of the negatives where there is a lot of single
> tonality area (like open sky) mostly on B&W negatives.
>
> Does anyone have a clue on how to minimize this moiré pattern problem?
> (and no, I'd rather not send my negs out to be drum scanned... <s>)
>

I used to experience a similar problem. In the center of my negatives,
I would get what looked like almost an oil immersion effect. Really
annoying. I solved the problem by flipping the negative over so that
it curved in the opposite direction (If you looked at the negative
end-on, the short egde was curved up, like a smile. That's when I
would see the problem. When I flipped over the negative such that the
short egde looked like a frown, that's when the problem would go away).

Kevin
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

"Terry Smith" <TMSmith.TakeThisOut@abriget.com> wrote:

> David, Thanks for the correction. I'm sure they are Newton's rings; I
> don't know why I called them Moiré patterns...

Then all you have to do is keep the film off the glass.

Which would be, I'd think, quite hard. Sigh. (In my experience, the emulsion
side down trick doesn't really work.)

David J. Littleboy
Tokyo, Japan
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

I had my custom 5x7 carrier made out of 4 ply flat black matte board.

Would a thicker matte board (or some other material) lessen the chance of
the film touching the glass? If so, how does the scanner know where to
focus???




"David J. Littleboy" <davidjl DeleteThis @gol.com> wrote in message
news:e4tdj0$r48$1@nnrp.gol.com...
>
> "Terry Smith" <TMSmith DeleteThis @abriget.com> wrote:
>
>> David, Thanks for the correction. I'm sure they are Newton's rings; I
>> don't know why I called them Moiré patterns...
>
> Then all you have to do is keep the film off the glass.
>
> Which would be, I'd think, quite hard. Sigh. (In my experience, the
> emulsion side down trick doesn't really work.)
>
> David J. Littleboy
> Tokyo, Japan
>
>
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

In article <e4tdj0$r48$1@nnrp.gol.com>,
"David J. Littleboy" <davidjl RemoveThis @gol.com> wrote:

.. (In my experience, the emulsion
> side down trick doesn't really work.)

"Y"
--
The sometimes insomniac.

www.gregblankphoto.com
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat.. 

"Terry Smith" <TMSmith RemoveThis @abriget.com> wrote:
>I had my custom 5x7 carrier made out of 4 ply flat black matte board.
>
> Would a thicker matte board (or some other material) lessen the chance of
> the film touching the glass? If so, how does the scanner know where to
> focus???

The Epson flatbed's don't focus. You need to test for optimal focus, and
hold the film at that distance above the glass. The new V700 (or V750)
provides means for doing that.

David J. Littleboy
Tokyo, Japan
 >> Stay informed about: Minimizing Moire patterns when scanning large format negat..