Anti-Newton Ring Glass??!!?!

[Dave Aharonian]

I'm hoping somebody can help with some info. I'm scanning 5x7 negs on a Microtek 1800f, placing the negs emulsion side down directly on the scanner glass. Sometimes the scans are perfect, other times there are lots of Newton Rings. I've been wet-mounting negs on the scanner glass with mixed results - the main problem being small bubbles in the liquid. I've read that some people use a sheet of anti-newton ring glass on top of the neg. How exactly does this work? I understand that between the neg and the AN glass there should be no rings, but wouldn't there still be rings between the scanner's glass and the negative? How does putting a piece of AN glass on top of the neg help - or am I missing something?

Thanks in advance!

Dave

[Daniel_Buck]

for my Epson 4990, I use the AN glass with frosted side facing down, negative with emulsion facing up against the AN glass. I stick a penny under each corner of the glass, so that the negative is suspensed above the scanner glass, with the negative touching only the AN glass. No rings!! :-D This works well for my 4990, because I believe it's actually focused *above* the scanner glass.

[Walter Calahan]

Place the negs emulsion up and then place a piece of anti-newton ring glass on top. Placed the anti-newton ring glass' 'frosted' side towards the emulsion.

I got my ANR glass here: http://www.fpointinc.com/glass.htm

[Songyun]

Place the negs emulsion up and then place a piece of anti-newton ring glass on top. Placed the anti-newton ring glass' 'frosted' side towards the emulsion.

I got my ANR glass here: http://www.fpointinc.com/glass.htm

which one did you get? 1mm , 2mm or 3mm?

[Daniel_Buck]

I would get the 3mm, I believe I have 2mm and it feels a little thin.

[buze]

Hmm having the emulsion up doesn't make much sense. It should be down, toward the lens; otherwise you are scanning thru the film base.
I scan the same way as Daniel, using run of the mill window "frosted glass" where I tape the film. The fact the 'frost' is against the smooth film base is enough to prevent any rings, and the scanner can focus on the real thing : the emulsion.

Also most film I tried have a tendency to blow slightly 'toward' the emulsion side, so taping it with the emulsion downward makes the film natural curve push itself flat against the glass.

I got a level of sharpness out of that 4990 I've never achieved before...

[Remigius]

frosted side down, emulsion down, film taped on bottom side of anr glass of better scanning film holder.