NuArc 26-1K

[Jeff Bannow]

jbannow, there are there hinges on the glass, probably 2 on the back, one handle @ front to be precise, my problem is the whole rubber bed shift too far towards the back, the edges of the back hinges were caught on the outer rubber rim, that leaves a gap.

check out yours I bet the rubber bed was shifted over, I just came out of the basement, spent whole noon time to clean it and re-Velcro the entire bed.. its working wonderfully..

and for the valve thing, I agree with Jeremy, you just have to adjust to a point, and every time as you fire up the pump, if will reach and stay there...

Now I am ready to get wet...

Thanks everyone.

Andrew

I'll definitely check that out. Thanks!

[Jim Fitzgerald]

Jim, these just sound too fun!

Okay, you guys these things are cool! I don't know where you get them as they came from my good friend Gordon Chapple's estate. They have these really cool dark green lenses that flip up to clear lenses. If i put the appropriate head gear on i don't need a Halloween costume! Sorry I don't know where to get them. maybe Welders goggles?


Jim

[Andrew ren]

Okay, you guys these things are cool! I don't know where you get them as they came from my good friend Gordon Chapple's estate. They have these really cool dark green lenses that flip up to clear lenses. If i put the appropriate head gear on i don't need a Halloween costume! Sorry I don't know where to get them. maybe Welders goggles?


Jim

I bought a 100% Uv a&B proof glassware from Marks work warehouse shop this afternoon here local.

[Jan Pedersen]

My rubber bed does move to but towards the front. It's not a big deal and i can print a few sessions before i need to reposition.
I have always used maximum vacum so perhaps i could try to turn it down a bit and maybe not have to reposition the rubber bed so often.

I don't remember where i bought my goggles but a google search should bring up some options. Don't use it without goggles unless you walk out of the room when you expose your paper. Eyes are not easily replaced.

[E Thomson]

Frankly I have no idea why anyone thinks they should be bleeding off the vacuum. The vacuum press will work at its most efficient (will hold the materials tightly registered) when it is allowed to operate at full force. The valve is there so you can release the vacuum quickly and open the lid. That's why it's labeled "Release" (on my 26-1KS). Just let out the vacuum by turning it counter-clockwise, then close it clockwise again.

My unit came with self-adhesive velcro holding the rubber mat and seal assembly in place so it doesn't shift. Strips of hook stuck to the metal bed and strips of loop stuck to the mat assembly.

My unit also came with a sheet of corrugated cardboard laid under the mat, but cut to a size that would fit loosely inside the vacuum area. This has the effect of lessening the volume (or empty height) of the cavity within the seal. If you are only pressing thin materials, it means the vacuum will draw more quickly.

[Colin Graham]

For digital negatives on some media, the vacuum can practically transfer the ink from the negative to the interleaf or emulsion if left all the way up. On my vacuum frame 5" of mercury is plenty to hold everything tightly sandwiched together, even with unruly carbon tissues. But then again mine is a DIY, so not sure about the nuarc.

[D. Bryant]

For digital negatives on some media, the vacuum can practically transfer the ink from the negative to the interleaf or emulsion if left all the way up. .

IMO, this is more of a function of the negative substrate than the vacuum setting. I've had this occur with products like Ultrafine Clear Film printed with colored ink. UCF works best with black inks, at least Epson black inks. This has never occurred with me using Pictorico or a Pictorico work alike such as Arista transparency film.

Never the less working at a reduced vacuum may help prevent loss of water content of an emulsion which is usually important to maintain consistency with most alt. processes. A work around is to place the negative and sensitized paper between sheets of mylar.

But this is probably old news for you,

Don Bryant

[Jason Greenberg Motamedi]

With some soft papers I notice that with full vacuum the NuArc rubber mat can leave marks which are difficult to remove, even after a long chemical soak.

[clay harmon]

The reason is that an excessive vacuum will dessicate a paper that has been coated. This is important with pt/pd processes because the sensitivity (printing speed), image color, and contrast of the paper are influenced by humidity. A too-dry palladium print will be slower, browner, lower contrast and have less dmax. A sheet of mylar between the back of the print and the blanket will help slow down this dessication, but a high vacuum and long exposure will eventually dry out the paper no matter what steps you take. Using the minimum vacuum to get good solid contact between the negative and and the coated paper will buy you some leeway.

Frankly I have no idea why anyone thinks they should be bleeding off the vacuum. The vacuum press will work at its most efficient (will hold the materials tightly registered) when it is allowed to operate at full force. The valve is there so you can release the vacuum quickly and open the lid. That's why it's labeled "Release" (on my 26-1KS). Just let out the vacuum by turning it counter-clockwise, then close it clockwise again.

[Andrew ren]

this is interesting.

just had a test, put a paper towel under the glass, cranked to 15, the marks left over @ the back of the paper seems "permanent".

so whats the "ideal" pressure for standard pt/pd printing then?