Not a Complete Failure...

Another try at bleaching a toning a cyanotype.


sonny rosenberg

2/6/20232 min read

This one is a little different. I bought an old 5x7 glass plate on Ebay that seemed to be in good condition. Happily, it turned out to be in as good of condition as it appeared on ebay. I also got this at quite a fair price, besides the cost, I was attracted to the image largely because it's a bus rather than someone stiffly posing for a portrait or handsome Victorian street scene (more power to the mundane!). It's a pretty cool old bus IMHO. I'm guessing the bus is from the 30s, when I suppose glass plate negatives were giving way to film negatives? I have no idea actually.

I really didn't have too high of hopes for this first test of a glass plate negative as I exposed it in my old 5x7 contact frame, I knew that the UV light going through two pieces of glass would probably need a much longer than normal exposure. Still, I wanted to try it with something similar to my normal cyanotype exposure times. My usual exposure is 20 or 25 minutes. This was exposed for about 35 minutes. Next time I'll try for an hour or so.

This was also the first time I've coated paper with a brush. I did a pretty bad job of it, allowing for a very inconsistent coating from sheet to sheet. Unfortuitously, this plate wound up exposed on one of the more thinly coated sheets, which as far as I can tell, only exacerbated its issues.

The bleaching and toning worked fairly well. I've come to the realization that toning in tannin requires bleaching. It seems that the bleach activates the tannin. I tried first with no bleaching, and even after several minutes soaking in the wine tannin solution, nothing really happened, but as soon as I very lightly bleached the image in a dilute sodium carbonate solution and then toned, the image began to acquire that beautiful purple black that tannin gives.

My highly sophisticated UV exposure rig. The image shown is not of the bus

As flawed as the image above is, I believe it shows that there's promise for me in this process. Soon I'll have the capability of relatively easily making 5x7 contact prints without resorting to digital negatives (not that there is anyhing inherently wrong with that). The experiments must go on!