Contact printing using a uv-plate burner..

[Danny van Ryswyk]

I can buy these uv-boxes used and new. All seem to have a timer, the first 2 are used, and the last I can buy new. (I want to make contact prints with digital negatives on liquid emulsion.)
I wonder if they are good for making contact prints..

 

[glbeas]

They are great for alt processes like platinum, salt prints, cyanotype. I think they might be too bright for liquid emulsion.

 

[rternbach]

I can buy these uv-boxes used and new. All seem to have a timer, the first 2 are used, and the last I can buy new. (I want to make contact prints with digital negatives on liquid emulsion.)
I wonder if they are good for making contact prints..

I'm not an expert but I have done some of what you're asking about. My suggestion is to contact the manufacturer of the emulsion or uv sensitive material you will be using and give them the specs on type and number of bulbs in the unit you'd like to use. To get this info you may want to contact the manufacturer/supplier of the tubes (visit the website?) to get the spectral output characteristics.

Enjoy!

 

[Nicholas Lindan]

Those aren't 'plate burners' - they are low-end exposure units for printed circuit boards and for DIY labels. The double sided one is for double sided printed circuit boards.

They are not a good choice for your purpose.

• Liquid Light is not a UV emulsion.
• They have poor contact pressure.
• The light is uncollimated.

Use a standard spring back contacting frame and a small light bulb hanging about 3 feet above the frame.

A plate burner will have a vacuum blanket to clamp the materials together and the light source will be a mercury vapor or HID lamp that is several feet from the frame. The smallest are about the size of a washing machine. There are also overhead units with the light above the contacting frame and a curtain that pulls around to shield you from the light.

There are boxes that are similar to plate burners made for exposing silk screens. The blanket system is not designed for flat a/w but for silk screen frames. Some of these units use banks of flourescent bulbs.

 

[Danny van Ryswyk]

Use a standard spring back contacting frame and a small light bulb hanging about 3 feet above the frame.

Nicholas, what kind of light bulb do you recommend?

 

[rternbach]

Nicholas-

Of course you're right but couldn't Dan hang one of the units pictured, with it's timer, in place of a single bulb?

-Rudy

 

[Nicholas Lindan]

The standard bulb used for contacting is a 7 1/2 watt round style. If you can find one nuArc made the CP25 point source contacting light that's quite nice: timer, adjustable brightness, VC filter holder on the lamp housing (though it wants 3" gels, not standard under-lens filters) - if you wait long enough you can usually find one for $25 or so.

For exposure control you can use an enlarger timer. Adams used a footswitch and metronome and he did a dance with his hands above the contact frame for dodging and burning.

 

[cowanw]

Or cobble a open bottomed box together and sit it on top of the Aqua blue one and set the spring back contact frame on top face side down. How high the box is will determine how far away from the light your print is (needs to be).

 

[Danny van Ryswyk]

Great info, thank you all so far, very helpful.

 

[JBrunner]

Silver emulsions are far too fast, and these units would have too much unpredictability on start up for any kind of consistency, as full exposure would likely be reached just after striking, for these to be of use for liquid light or similar silver based emulsions.

For silver contact printing I use my unfocused enlarger as a light source. Very controllable, allowing for stopping down to extend exposure times, which is more often what is needed.

 

[Nicholas Lindan]

Edward Weston's darkroom - you can see the bulb hanging above the contact printing frame at the right side of the picture.

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