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banana_legs
02-28-2011, 05:58 PM
Just before Christmas, I noticed an addition someone had made to the canal. It must have seemed like a good idea at the time.

The cyanotype is a contact print off a 4x5 negative that was a test shot to establish a workable development process; the film is Kodak Ortho-X that appears to be from an early 1938 batch. The film is no good at its rated 125 ISO, but I have found that shooting at EI6 and then developing by inspection in paper developer seems to work really well with almost no fog on the negative. The film is actually half plate, but I still have not found time to make any bellows for my half-plate camera.

The camera was my home-brew 4x5 view camera with a 90mm lens at f/22 for 1 second.

Best regards,

Evan

PS. The observant will notice the notches that code my film holder are prominent along the top of the image, but also just visible is the single rectangular notch in the film, not the usual 3 notches for Ortho-X, hence the apparent 1938 date. Attached files http://f295.f295.org/uploads/bike_in_canal_4x5view_90mm__918.jpg (http://f295.f295.org/uploads/bike_in_canal_4x5view_90mm__918.jpg)

Doug K
03-04-2011, 10:28 PM
Excellent image. The tonal range is awesome with all the subtle details. Is this a traditional 2 part cyanotype? I've found I get better tonal range with an initial acid developer bath before finishing in water. How did you develop this?

banana_legs
03-05-2011, 10:57 AM
Thanks Doug.

The negatives being so old seem to develop best when left quite thin and are therefore ideal for cyanotype. The details on the actual print are astounding; you can see the tread pattern on the bike tyre and all the twigs on the tree; its a shame the web image does not show all the detail.

I use the classic formula with a 1:1 mix of parts A and B. My tap water is slightly alkaline so I develop in 1L of water to which I add 1.5ml of 10% hydrochloric acid; if I develop just in water, I lose quite a bit of density. I wash the print in distilled water that I condense out from the exhaust of my tumble drier.

Best regards,

Evan

Doug K
03-05-2011, 04:23 PM
Thanks for sharing the details, Evan. You confirmed my guess.

I've used both vinegar (about 100 ml of 4% in 3 liters) and a 1% citric acid solution. I'm too lazy to compare the chemistry right now. Naturally it all depends on what the chemistry of your water is as well. Our water here is slightly alkaline as well. Cities do this as an anti-corrosion measure. Ware recommends nitric acid with his process, and I will try that too some time.

Doug