Monday, April 18, 2011

Space Bag Contact Printer--Results are In

After a bunch of talk, I finally tried exposing a solar plate in the sun using a contact printer of sorts. I gave my space bag a trial run shown in this picture. (After going to two stores, imagine my consternation when I saw a logo and crap printed on the bags as I pulled them out of the box. What?!! Luckily the back of the bags are logo and swirly-free.)

Unfortunately today is cloudy. In the spirit of experimentation and not letting nature keep me down, I went forth anyway, since the forecast for the entire week is cloud cover. I exposed my plates at high noon so I could use it as a benchmark for future exposures. I checked the UV rating on www.wunderground.com and it reads 0 out of 16. That can't be right. I am undeterred. 

First, my supplies and associated costs:
  • Original Space Bag, size large (2 in package)--$9.99
  • Black Poster Board (I'll cut to size of canvas board so I don't have to paint it)--$.99
  • 8 x 10" Solar Plate--$16.00
  • canvas board (fresh out of convenient sized plywood, but this seems to be working fine)--already had it
  • 3M Multipurpose Transparency Film, CG6000--already had it, but it costs about $35 for a box of 50
  • Photoshop--already had it
  • Baby powder--$3
  • Soft brush--already had it
  • Tray for water bath--already had it
My steps:
  1. To get ready for the big exposure, the first thing I needed to do was cut my poster board down to the size of my canvas board and give the space bag a trial run.
  2. Get Transparency ready. I already had my image scanned so I just opened it in Photoshop (I have version 5.5 which is probably super old) and converted it to Grayscale. Under Image>Mode>Bitmap, I changed my output to 300dpi, then under Method, selected Diffusion Dither. I then printed out my image on transparency on my 300dpi LaserJet.
  3. Next, I cut a test strip out of my first sacrificial solar plate in order to test exposure times. It's important that your solar plate be cut so that it doesn't warp, which might result in uneven exposure. In the WPA studio, which has no windows, I turned off the lights and put on my handy red headlamp that we use when camping, put the plate face down on a cutting mat and used a utility knife and ruler to cut the steel backed plate. I don't recommend this, at least for the .34 plates that I have. A paper cutter would do a better job. However, I'm continuing, still undeterred. (You can see in the picture below where the plate was slightly warped--on the wording side. It's barely recognizable.) 
  4. Next I dusted baby powder onto the surface of my mini plate to keep them from sticking to the transparency, and one by one exposed them for 1.5 minutes, 3 minutes, 5 minutes respectively, in my super duper, space bag contact printer, pictured above. (I was doing this in the dark essentially, so my vacuum seal wasn't superb. I plan on buying a yellow bug lamp and using that instead. It'll be brighter and I'll be able to see what I'm doing.)
  5. Next I developed my plates in a water bath for about 2 mins, scrubbing with an old dish brush--still in headlamp but the door is open with the hall light on. I then blotted my plates with a paper towel and put them back in the sun to harden for 10 more minutes. I can see the images burned into the plates and I'm getting excited about printing them!!
  6. Time to print. I'm using Akua ink and trying Arches lightweight and rice paper since I've had success with it before. The Arches is a beautiful creamy color that you can't really detect in the picture below. (Rice paper on top, Arches on bottom.)
My Results in 1.5, 3, and 5 mins exposure lengths (there is a flaw in the toner cartridge of my LaserJet, and that's what the line is on the 1.5 min exposure--it was on my transparency) :


What I don't understand is the 1.5 min exposure looks the darkest. The forehead lines are holding a lot of ink and bleeding a bit. It's either a problem with the dithering of the file in Photoshop or the transparency to plate contact wasn't great during exposure for the 3 and 5 mins times. I think I'll investigate buying or making a separate halftone screen and expose my plates twice, so the areas that are reading black will actually be made up of little dots vs. a valley. That's got to improve things anyway.

I have to admit I'm pleased with such a lo-tech method! I think I'm interested in learning more about this technique, which is good because I have 4 more 8 x 10" solar plates and they have a limited shelf life. 

    2 comments:

    Junanne said...

    Now I have to go buy a space bag..is their no end..hehehe..thanks for all the information and sharing ...I will try this......

    Cathy Savage said...

    I totally know what you mean! I need a new process like I need a hole in the head. And my 10 x 10' home studio is stuffed--one more piece of paper and the foundation under it just might give. My excuse to buy the space bag was that if it didn't work, I could use if for my blankets. :)