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-   -   contact printing frame (http://www.film-and-darkroom-user.org.uk/forum/showthread.php?t=13657)

NeilCannon 22nd February 2021 05:28 AM

contact printing frame
 
Hello, contact printing frame's look really expensive, so I thought I'd make my own. I have a question regarding the glass, does it have to be a specific type? I have some float glass, from framing, so has a slight green tint to it, will this affect the processing?

Many thanks,

Neil.

Bob 22nd February 2021 12:25 PM

Welcome aboard.

Glass blocks UV-B but allows most UV-A through. I believe wavelengths in the UV-A range are what alternative processes require so pretty much any glass should do the job. A green tint should not be an issue as UV wavelengths are a long way from green.

However, a green tint might affect silver based variable contrast papers as they use green to control the low-contrast exposure but I don't know if the very feint tint in window glass would be enough to make a noticeable difference.

That's the theory, but I do not use alt. procs so I leave it to others to provide the practical! :)

The only caveat I might make is that window glass breaks in dangerous ways so if it will be used by little hands, perhaps go for toughened safety glass.

Cheers, Bob.

Terry S 22nd February 2021 12:57 PM

Yeah, I'd recommend that you seek out a local glazier and get a bit of toughened glass as well. I did this many moons ago and it didn't cost much more than 'ordinary' glass for sale.

Terry S

alexmuir 22nd February 2021 02:09 PM

I tried to re-glaze some old frames myself using float glass bought for picture frames. I couldn’t cut it accurately, so I took the wooden frames to a professional picture framer. He cut several pieces of glass to fit, so that I have spares.
It was just standard picture frame glass, and works fine for normal contacts. I haven’t tried any alternative process with these frames.
Alex


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Nat Polton 22nd February 2021 02:38 PM

Picture frame glass tends to be quite thin.
A thicker glass might be more suitable considering the bumping around that the contact frame might experience during use.

Cheers.

alexmuir 22nd February 2021 03:12 PM

The frames I have are only 4x5. If it’s something like 8x10, or larger, a heavier glass would be best.
I can recommend the Printfile model which, I think, is 10x12. It’s actually quite reasonably priced compared to others.
Alex


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NeilCannon 22nd February 2021 04:19 PM

Fantastic, thanks for the prompt replies, I've done a bit of framing, so can cut the glass to size, but it sounds like the 3mm glass I have will be a bit too thin. I'll look for some thicker stuff. Cheers.


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