View Full Version : Simplest Contact Printing Method for 7x17?

Robert McClure
1-May-2005, 20:34
Hello Everyone!

Would welcome your comments. Thanks very much!

My assumption: two sheets of 1/4" plate glass ought to be adequate for contacting 7x17 negatives. Right or wrong? I assume further that a regular frame (with "springs") might give the added benefit of eliminating slippage of negative and paper. But I could live, temporarily, without that.

Back to the two sheets of plate glass. Would not the weight of the glass, itself, press film to paper snugly enough to yield adequate prints? Any need for special glass?

Any of you who might be just getting started like me now working with simple glass? I can see no reason why this would not be adequate for 7x17 prints. It worked with 4x5 and 8x10.

Many Thanks!!

Michael Kadillak
1-May-2005, 20:49
Go for it Robert! Adequate? By all means. Like you said, if it worked for the other formats that you worked with to your satisfaction, then you should be pleased. Think of it as doing two 8x10's side by side.

From my reference point after trying many alternatives, the only thing I find truly acceptable is a vacuum frame pulling about 20#.

Enough said,


John Kasaian
1-May-2005, 20:53

I can't say about 7x17 specifically, but I use a sheet of table top glass from an import store---used for making end tables out of tribal drums or coffee tables out of camel saddles of something llike that---anyway these are thick pieces of glass and Pier 1 and Cost Plus sells them in various sizes with nicely finished edges. The bottom of the sandwich is a piece of firm rubber matting with no pattern or tread. I think it came from Orchard Hardware. Flattens things out nicely. Maybe its overkill but I've got no complaints.


Oren Grad
1-May-2005, 21:00
Robert -

I've used the glass sandwich approach successfully for formats up through 8x10. But based on what I've read and heard from others, there's some doubt about whether it will reliably do the trick for ULF. Two potential problems are ability to maintain adequate contact for full contact-quality sharpness across a large sheet of double-weight paper, and ability to maintain sufficiently even pressure to avoid Newton's rings. Another practical issue is the sheer weight of a really large piece of quarter-inch glass, which gets to be quite literally a pain to sling around.

With regular spring-back contact printing frames, Newton's rings can be a problem - some users say they have problems, others say they don't. If you search the other threads here you'll find plenty about that, although much of the discussion is focused on 8x10 or smaller rather than specifically on ULF. Conceivably some spring-back frames have a design that's less prone to Newton's rings, but I don't think anyone's ever reported controlled tests to prove that, and my own spring-back frames certainly don't qualify.

I've ended up investing in a vacuum frame for my 11x14 and 7x17 experiments. Just arrived recently, though, and I haven't had a chance to try it yet.

Steve Sherman
1-May-2005, 21:40
I had an older 16X20 wooden contact printing frame which yeilded so so results. Recently purchased a vacuum frame and couldn't beleive the difference in image sharpness. Couldn't recommend a more important piece of equipment if one is contact printing anything above 8X10.

Clayton Tume
2-May-2005, 03:05

2 pieces of glass will work just fine, last week I printed some 8x50 negs with 1/4 inch glass top and bottom. Been doing it that way for years as I never got around to building a proper contact printer.


John D Gerndt
2-May-2005, 14:50
There was an article a while back that asked if paper was sharp enough to capture what was on a negative. It is, but with one caveat: you need a lot of pressure to get the most out of contact printing. This leads me to believe that though 1/4 inch glass might do well, a pressure applied to that glass might do better. I am working on a contact printer for 12x20 negs right now. When I have a good solution I will post it.


Robert McClure
3-May-2005, 07:15
Wow! Thanks, guys. As usual many thought-provoking answers!!

Michael - Makes sense to me. Glass sandwich will be adequate for starters. Thanks! But, as I had suspected, more pressure via vacuum couldn't help but do better. I'll look at that later. (I think I recall Sandy King saying the same thing about vacuum. I wonder if he actually produced two prints from the same negative and then compared. The issue I guess becomes how significant the difference and what it is I want to accomplish.

John Kasaian - Yep, I'll start with Pier 1. What, exactly, is your thought behind the padding? And what do you mean by its flattening things out? Thanks!

Oren - please let us know how your VF works out. I will be curious. Guessing neighborhood of $500-$700 for 20x24 frame and pump. I will read the other threads. Thanks!

Steve - another vote for vacuum frame, I see. BTW, I'm shortly going to ask for just a few clarifications on terminoligies in your last VCM article on stand development. Sure would like to hear from the guy who wrote it! Many thanks in advance!

Clayton - thank you. I like cheap and easy, too.

John Gerndt - thank you, too. Was the article in VCM? I will look thru past issues.

Best Regards