Cyanotype is a method of print making that has many advantages to a modern printer. It's easy, cheap, produces high quality images, and can be toned into many colors beyond its natural blue.
The cyanotype process is most sensitive to UV and fairly slow, makding it unsuitable to use with traditional enlargers. Given that our best method for making larger prints is to make contact prints. Historically this meant that in order to make large prints you had to make large negatives, but with the advent of high quality inkjet printers we're able to print a high resolution digital transparency and use that instead. As print makers this gives us all of the powers of digital processing; digital editing, collage, adjustments; At the cost of having to sit in front of a computer.
Once you have a transparency, making a cyanotype isn't complicated. First the paper is coated. Starting with a suitable paper the sensitizzer is spread onto the paper and then the paper is dried. Then the print is exposed. The transparency is squeezed against the sensitized paper and exposed to bright UV light. Then the print is developed. Washing it in a bath of acidified water, then a bath of dilute hydrogen peroxide, then finally a long wash of running tap water. Finally the print is dried. At the end you should have a lovely bright blue print.
See Cyanotype for full instructions on how to mix and prepare either classic or "new" cyanotype.
Before coating there is some work to be done with the paper. If your paper isn't already cut to the right size you'll want to spend some time deciding what size print you want to make and ensuring your negative looks nice on it. I take this time to make some notes in pencil, this does two things, first many papers have different tooth on both sides. This is the time where I pick what is the front or the back, and making a note will help me remember when it comes time to coat.
This is also the time where I'll make note of the hummidity. I've found that paper that is excessively dry or wet wont take sensitizer properly and you can end up with issues in the print. If the room is below 40% relative hummidity I'll let the paper sit on a screen over a tray of warm water for 30 - 40 minutes before coating.
Materials:
The first thing I do is I get out my brush and I place it in a small bowl of distilled water and move it around to knock out all the air bubbles. This helps hydrate the brush so that it doesn't absorb all the sensitizer.
Next I prepare my sensitizer for coating, using new cyanotype, I measure aproximately 2ml of sensitizer per 8x10 print, then add 1 drop of tween 20 and 1 drop of citric acid solution for every ml of sensitizer. I then swirl this mixture for a while to ensure that it's well mixed.
Now I lay my paper out on the glass sheet. I take my brush out of the water, running it over the edge of the bowl to remove excess water, then I paint 1 or two strokes on the paper towel to further dry the brush.Then I just touch the tip of the brush into the sensitizer.
With the sensitized brush, starting a the top left of my print area, moving left to rigt top to bottom and begin to coat the print in light (almost no pressure), smooth, medium speed strokes. If at any point the brush gets dry I return it to the sensitizer and continue. When I've coated the full print area, I rotate the print counter clockwise and begin again, top to bottom, left to right. At this point I angle the print in the bias and do one more final pass top the bottom left to right.
Some things to watch out for:
Once your print is coated hang it from a line with the clothes pin and let it sit for about an hour or until it is dry and cool to the touch.