Newtons Rings? - replace your scanner glass!greenspun.com : LUSENET : Large format photography : One Thread
I'm new to this board and I just responded to a question about solving Newtons rings when scanning negs/trannys on 'consumer' flatbed scanners. I then saw this was a common problem people were having and I decided to post the method I have used to solve this perenial problem! Quite simply replace the standard glass in your scanner with some non reflective picture frame glass and sandwich your film with with another plate of the same on the top! Non reflective glass has a 'very' fine etched surface on one side - this eliminates Newtons rings very effectivley. Most film adaptors hold the film away from the glass but I still find that under the heat of the lamp they bend and touch the glass - additionaly most scanners are focused on the glass surface so any seperation of the film from this undesireable. I have not managed to pick up the 'etching' as a texture on my scans but I managed to get a couple of choices at the framer's and chose the least etched. I did this mod to an Epson 1640SU - the glass was held in place with some double sided sticky tape and was simple to get out. If anyone has one of these (or the 1200 range which shares the same chassis) and wants to do it they can e-mail me and I will give them the glass sizes and a 'trick' to get the top off without fouling the head.
-- John Griffin (email@example.com), November 06, 2001
Sounds like a complicated solution to a non-problem to me.
The emulsion side of film is usually too rough to give problems with Newton's rings, so only the back of the film needs to be in contact with anti-newton glass.
If you place the film emulsion side down on the scanner platen there should be no problem with rings, no need to risk the reduction in sharpness that anti-newton glass can give, and no need to void the scanner warranty by taking it apart.
Of course, the scan is then the wrong way round, but that's what the 'mirror' or 'flip' tool is for, isn't it?
-- Pete Andrews (firstname.lastname@example.org), November 07, 2001.
It's never been a 'non problem' to me or many others who use tranny film which has no 'roughside' - you get rings either way round! The etching is so fine that the scanner just can't pick it up and as there is another bit of glass pressing it down from the top it can't scatter the light. Good point about voiding the warranty but I'm a proffesional - these scanners cost the price of 4 boxes of quickload film -I don't care as long as it gets me the results - which it does.
-- john Griffin (email@example.com), November 07, 2001.
Wouldn't AR coated glass be a better choice? TruView, Denglas, etc., available from the same framing sources as etched "non-glare" glass.
-- Sal Santamaura (firstname.lastname@example.org), November 07, 2001.
I have the same scanner and the same problem. Reality check: if you put emulsion down on the platen glass, you get a normally-oriented image. Think about it! (unless you shot through the film base in your camera - not recommended!)Otherwise, how could you scan a print in 'opaque original' mode? BTW, I checked again, my 4x5 trannies are smooth, too ;-)
-- Paul Chaplo (email@example.com), November 08, 2001.
Reality double check.
You have to view a negative or slide through the base for it to be right-reading.
-- Pete Andrews (firstname.lastname@example.org), November 12, 2001.