# Help, Odd pattern on my prints.



## PlasticSpanner (Mar 8, 2006)

I sometimes get an odd swirly pattern on my prints from where the negative touches the glass in the holder & creates a pattern similar to oil spreading on water. (but only on the glossy, non emulsion side)

I've completely degreased the glass and tried fresh negs never touched with greasy fingers but still seem to get it sometimes. I don't really want to change to a glassless holder though because I like the crisp images from a completely flat negative especially with astro stuff.

Can anybody tell me what may be the cause of this problem or suggest a different way to clean the negs/glass?

Many thanks. :thumbup:


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## ThomThomsk (Mar 8, 2006)

Newton's rings?

http://van.hep.uiuc.edu/Van/qa/section/Light_and_Sound/Diffraction/20021028002405.htm

Thomsk


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## PlasticSpanner (Mar 8, 2006)

Very similar in appearance to the close up pic of the Newtons rings but that isn't the cause.  The pattern can be seen on the glass/negative combination in the holder before it's placed inside the enlarger.  The pattern is also not circular but random shapes and isn't apparent on all the negatives.

It must be something to do with the contact between the gloss side of the negative and the glass plate above, but like I've said the glass is spotless and de-greased and the negative is fresh from the tank and has never been touched with fingers apart from the edges.  (not the sprocket holes, the absolute edges)


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## PlasticSpanner (Mar 8, 2006)

Should I get rid of the top glass & replace it with a "mask"?

It just seems to be the glass & gloss causing the problem.


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## ThomThomsk (Mar 8, 2006)

At least you would then know for sure if the top glass is the problem. Have you tried asking about this over on the APUG enlarging forum?

http://www.apug.org/forums/forumdisplay.php?f=41

Thomsk


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## Philip Weir (Apr 29, 2006)

It sounds to me like "Newtons Ring" they don't need to be perfectly circular. Use a glassless carrier, it's the best way to go and also avoids four glass surfaces which collect dust. Stop down further if your'e worried about the image being slightly out og focus. Philip.


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