Using heat and acid to reduce cyanotype exposure times!
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- เผยแพร่เมื่อ 8 ก.พ. 2022
- In this video I am re visiting some tests I did a few years ago on trying to reduce exposure times for cyanotypes. The main reason for this was because back when I was running these tests I had not optimized my UV light source or negatives for use in projection/enlargement . So i am re visiting these tests I did to see if there is still anything useful from them. I believe if everything is optimized 30 minute exposures could be possible for a 8X10 cyanotype enlargement! I am going to upload a bonus video after this one where I take some of these principles and attempt to make a 24"X48" cyanotype!
See my other videos on how to modify a projector to do the same types of enlargements!
I add citric acid to the mixed cyanotype solution. And also vinegar to the first bath. I’ve been thinking about heat during exposure today and that’s what led me to your video. Thanks for making it. 🙂
Does citric acid lowers exposure time?
I've been using vinegar with water to develop in camera cyanotypes it works extremely well for reducing exposure. It's at least one stop if not two.
Really great video btw very interesting how much the heat together with the vinegar does.
Very helpful, i am very keen to tinker around :) thanks for sharing!
greetings from germany
Amazing tests and results ! Very important work!
Thank you!
Hi what a great idea with the proyector ! Can you tell us where to buy it ?
Thanks for sharing all your experiments! What would happen if you increased the strength of the solution or added the vinegar to the solution?
I would assume you can use several different acids like citric or oxalic, you can get gallic acid concentrate as well. You would have to test to see if anything stronger would help or hurt but I would imagine that at a certain level it would just convert everything to blue and wash out the image. As for adding it to the solution the only time I have ever heard of doing that is in glass cyanotypes which I have made and it takes a small amount of oxalic acid in the emulsion, although I have not tested it on paper I would assume it could speed up the exposure as well.
Thanks for testing them I had tried with a video projector but the time was very long and the image blurred. Do you use a video projector or a dispositive projector? Doesn't it consume too much electricity from the lighter for several hours?
I was using a modified film slide projector but a video projector should work as well
Wonderful video! Question: Did you ever try using an electric heater to heat the paper?
I have. Essentially any type of heater will work as long as you can keep the coated paper from moving around, I used infrared lamps to prevent any kind of buckling but any heat source should work
If you put a regulated heating pad behind the easel, would that be an easier way to do testing? I was thinking about an aluminum plate as the easel with a heating pad (reptile warmer) behind it. The slight buckling of a negative with a high intensity UV COB that could influence sharpness might be due to heat. I think a water cooled heat sink might make a difference. Temperature of the acid cyanotype developer/toner/bleaches might make a difference as well, though I have not tested that. I've used a citric acid rinse for my cyanotypes in all stages, though I am working on reducing it down as far as possible to not lose rich blues. The ph of my tap water is 9. Consistently. I have to acifify it.
The audio fades out on part of your video.
There is no buckling on the negative when you are dealing with 380nm LED light, even up to 100 watts it does not produce enough heat to affect the negative which is why I moved to that wavelength. As far as heat there are better devices such as high temperature heating pads and other things as well but for demonstration purposes the heat bulb works fine. You could possibly make the exposure time even shorter with temperatures over 100F but I would imagine that there is a point where it would do more harm than good. My tap water is loaded with dissolved limestone which causes all kinds of issues, I have read about paper acidification as well as developing in acidified solution and have had some ideas about acidifying the cyanotype solution itself although I have not tested this. You add oxalic acid to cyanotype emulsion for glass plate cyanotypes and I noticed that on this same system it was only a 30 minute exposure time, I do not know if it was because of the acid of the nature of exposing on glass itself being the reason for this. I think perhaps this would be another idea to test out and see.
And yes sorry about the audio in that section still getting microphones ironed out.
Hello friend, let me ask you, the led you use in the projector is white light? or a UV one? In the video seems quite green but maybe thats the whitebalance of the camera
It is a UV led
I am surprised that you got the Canson XL to work. My test sheet started to turn blue after 4 hours and by 12 hours it was almost fully "exposed" when i did a test peint. Canson has an alky buffer in it, calcium carbonate.
You are correct about the blue color over a short period of time and normally that would happen to me but the only thing I can think of is that it has something to do with humidity. Last time I ran these tests the humidity in my basement was anywhere from 55% to 70% and this time it is anywhere from 30% to 45%. I had assumed the paper was somehow acid buffered as it turns blue and I have only witnessed this in the presence of acid. Usually when the paper is alkaline it goes pale and blue fades away. I may do a video on testing the papers PH using a blender and PH strips to see what each paper is which would kind of help people decide on what to use for there application. I have made literally hundreds of prints on Canson XL so ether way it seems to work.
@@matthewbary1 Thanks
@@Pixelwaster No problem