Gum printer and educator Peter J. Blackburn shares two simple, experience-based tips for making gum bichromate printing more approachable. He challenges unnecessarily complicated workflows and shows two options for lighting: The sun and indoors.
There is no shortage of instructions and opinions for creating gum prints, my writings included. But it seems the more I print, the more I learn, and the more I learn, the more the stack of ideas grows. So, this short article adds more writing to the pile detailing a scattering of bits and bobs of ideas that some gum printers, both new and experienced, might find helpful.
The thread in this piece is simplicity. It is written in response to so much gum instruction, I believe, that needlessly complicates gum printing.
Using the sun for gum printing
Here’s item number one for simplicity. Try the sun for your exposures. It’s free and requires no electricity, extension cords, switches, or replacement parts. Just keep away from clouds, haze, dusk, and dawn. Those conditions mess with your UV. Ideally, print from late morning to early afternoon.
- Use a small (3 inches by 5 inches) negative to test for proper exposure.
- Start with an exposure lasting 10 minutes.
- Then soak your print to process it.
If the image falls completely off, double or triple your time for your next print. If the image will not process or is very blocked, ease off your exposure time by half or more. When your exposure is determined, you can print with your larger paper with confidence and less waste. There are more professional ways to determine exposure, and I will share some of those options in the future.
Indoor gum printing
If you desire to stay indoors and mainly create images 8×10 (inches) or smaller, you might want to invest in a simple dome-reflector-style lamp. Smith-Victor makes a nice unit, such as the Model A-12. Check your favorite e-commerce auction vendor for a gently used purchase. The bulb I use for my A-12 setup is the Philips 23-watt Mini Twister (6500K, 1600 lumens).
How to print:
- Place the unit directly on top of your negative/paper, being sure the dome completely covers your image.
- When you have determined your exposure using a smaller test print, you can use that exposure time every time you print with the exact emulsion/paper/negative combination.
Simplicity is achieved with consistent practice and when equipment is kept basic, affordable, and reliable. I’ll share more simple ideas next time.
World Anthotype Day
World Cyanotype Day
Hello Phil! Apparently it does. After my prints are exposed for the appropriate amount of time (usually around 15-30 minutes depending on other variables), they soak in water until the image is revealed. Were there no UV, the mixture would simply wash down the drain. I have used this bulb since I became aware of it almost ten years ago. Before that, I used hot tungsten photographic bulbs. They also work.
If you browse through some of my most recent articles on this site, the majority of the gum and casein work used for illustration was produced using the Philips bulbs. I hope this information help you. All the best to you.
Does the bulb actually emit UV which is required for Exposure?
Philips 23-watt Mini Twister (6500K, 1600 lumens).