I have a piece of mystery equipment and was hoping that someone could help me figure out how it works….
It is a NuArc N1000 Instant Mercury Printer, a vapor table top exposing unit that I understand could be used to make photopolymer plates. I am attaching images of the equipment. Unfortunately, I have no idea how this would work since I am only used to making polymer plates with a proper platemaker with a washup unit.
Has anyone ever used this equipment to make a photopolymer plate or maybe has access to a manual?
Any help or advice is appreciated. Thanks!
One of the reasons these types of exposure units can be made to work, but not work anywhere near as well as the units built specifically for relief photopolymer has to do with the light arrangement. Relief plates and offset plates both have photopolymer emulsions sensitive to the same part of the light spectrum, though relief plates have thicker emulsions needing more light. But the AMOUNT of light hitting the exposure plane is much less in an offset platemaker, by the law of inverse square. That is, if the lamp in an offset platemaker is, say, four times as far from the emulsion as it is in a relief platemaker, then it provides 1/16 the amount of light (and the distance is actually more than four times). Then, no matter what the wattage of the lamp in the offset platemaker, the relief platemakers have multiple lamps, eight or more, giving coverage to the entire frame, at close distance.
But we all tend to do things on the cheap until we can afford better. I used the NuArc 26-1K for over fifteen years exposing relief plates, but once I got a Ludlow PL-150 photopolymer exposure unit the quality improved considerably, and is even better with the present ReliefMate. But if one was getting an offset plate burner for free–and dealers have no market for them now due to CTP technology–it is a way to get started. You can always build a UV-tube box to nest over the contact frame.
Vida
These have been used for processing photopolymer plates but that is not their purpose. And will likely not serve you well either. Eric has had a great deal of experience in the printing world and can make this work. Let me repeat that without quoting it. But this does not mean that you can replicate his achievement, I certainly could not.
I guess what I am saying is either find a machine specifically manufactured for processing photopolymer plates or purchase your plates from someone who furnishes such processing. It will be far less frustrating.
Gerald
http://BielerPress.blogspot.com
Just to add my $.02… most platemakers produce their vacuum pressure with a frosted vinyl material called kreene. This not only creates the contact for the exposure, but also acts as a diffuser. It can be purchased from any platemaker supplier (Boxcar for example) and is quite cheap.
If you’re feeling frugal however, I think it is not too different from frosted vinyl from a fabric supply house (like JoAnn’s). You could probably add this either above or below the glass (inside or outside the vacuum, it may not matter at this point…) But what this may do to add time on an already slow exposure, I’m not sure.
Good luck!
Thank you so much Eric! This is really helpful. I will do some tests following your advice.
I used a NuArc 26-1K exposure unit to expose photopolymer relief plates for many years. This unit is similar in function. It can work but is far from ideal, and exposures will be much longer than on a proper photopolymer relief unit. I had exposures as long as 40 minutes when the lamp was getting weaker.
You will need to prep negs and plate material (back-trimming all four plate edges) carefully when using the glass contact frame, as there can be air pockets trapped that will spoil the plate. The vaccum system has a bleed valve that you need to use; partly open, the majority of the air will be withdrawn and after the material is drawn up to the glass you slowly close the valve to evacuate all the remaining air. When that happens you will see an interference pattern called Newton’s Rings which indicate good contact; you may also see any dust or hair that may require you to shut off the vacuum, clean the glass and negative and start over.
Note that this is a point-light source with the chamber painted black to reduce reflection. Photopolymer relief platemakers have multiple bulbs that expose the plate from many dfferent angles. Placing white paper over the black walls may improve plate formation and certainly reduce exposure time.