Tuesday, August 03, 2010

Using the Exposure Unit

A few weeks ago I tweeted that I loved McClain's photopolymer exposure unit, and I got a few questions and requests to learn more, so I thought I'd share my experiences with everyone here. This isn't my light box, it's Asheville BookWork's, and although it was my first time using it a few weeks ago, Frank Brannon has been working with it for a few months and came up with these ingenious designs to make it more user-friendly.

The exposure unit from McClain's is only a part of this whole assembly - just the box itself. Frank hinged it on the bottom right edge to a wooden base and added a darkroom timer. The little black square you see glued to the base is a piece of foam to protect the handle when you open it fully.

Here's another view.

The unit comes with the timer that you see on the front, but it's hard to get an accurate reading of exactly how much time it's set for. Having the large darkroom timer makes it possible to be very exact. I exposed my plates for 1min 30 sec, and it was perfect for line drawings and some type - the type was 12 pt. Old Newspaper Types, fairly large and already has a 'rough' look. I would play around with the exposure time for smaller or more delicate type.

Here it is opened. The black square is another piece of foam padding, also glued in place. This is where you put the photopolymer plate.

A piece of glass cut to the size needed for the plate and two heavy weights are used to create good contact between the negative and the plate (the weight have felt feet). We have about 6 different sizes of glass sheets. Another good option is to use a contact frame to press the negative tightly to the plate.

Here is how it would look in position to expose a plate. I had surprisingly good results, since I'm used to exposing plates in a vacuum table and was expecting poor contact with light bleeding through. All of my plates turned out perfectly on the first exposure!

All of the plates were made in a dimly lit room, of course. I'll be using the same exposure unit to teach this fall at Warren Wilson College, and will probably create the same set-up except for one difference - instead of using sheets of glass and weights, I'm going to stick with using just contact frames instead. It just seems safer and easier to have fewer parts and pieces to keep up with in a classroom environment. Sorry I don't have any images of the contact frames... I'll post some more photos after I get the set up ready to go at WWC.

This is one of the prints, a page out of my current book project, a reprinting of the book Spoon River Anthology.


BookGirl said...

Now you HAVE to do a class for those of us who want to learn, Jessica. Thanks for the post.


Jessica C. White said...

Clara - we'll do this in the Printed Book class, and I'm going to teach a special segment on how to print the type without cranking up a Vandercook, just for you! (and everyone else who's asked for it).