karavelov
Member
Hello,
I have some experience in lith printing (mainly with non-formaledihyde developers). Some of my recent lithprints could be seen here:
http://flickr.com/photos/karavelov/
I decided to try a formaldehyde developer and mixed a batch of Ansco 79b. I have tried it with different papers I usually work with (Forte Fortezo, Polywarmtone, AGFA MCP, ORWO and old stocks of FOHAR). I have encountered some strange phenomena I could not explain, so I ask for your wisdom.
1. With all papers there is strong green cast in highlights. This goes versus all my previous experience in lithprinting. What could be the source of it? (Later I could post a scan)
2. Development goes to completion in more than half an hour. That is very slow compared to my previous experience. I have tried to speed it up with a little of carbonate with mixed results. And the green cast disappears. I have mixed the developer in hot water without results. For the next batch I will omit the bromide and half the boric acid. Is this reasonable? What is the function of the boric acid in the mix?
3. Does surplus of formaldehyde affect somehow the development process? I ask because by paraformadehyde is not dry, it is more like a paste and I could not measure it exactly.
Thanks in advance for all suggestions
luben
I have some experience in lith printing (mainly with non-formaledihyde developers). Some of my recent lithprints could be seen here:
http://flickr.com/photos/karavelov/
I decided to try a formaldehyde developer and mixed a batch of Ansco 79b. I have tried it with different papers I usually work with (Forte Fortezo, Polywarmtone, AGFA MCP, ORWO and old stocks of FOHAR). I have encountered some strange phenomena I could not explain, so I ask for your wisdom.
1. With all papers there is strong green cast in highlights. This goes versus all my previous experience in lithprinting. What could be the source of it? (Later I could post a scan)
2. Development goes to completion in more than half an hour. That is very slow compared to my previous experience. I have tried to speed it up with a little of carbonate with mixed results. And the green cast disappears. I have mixed the developer in hot water without results. For the next batch I will omit the bromide and half the boric acid. Is this reasonable? What is the function of the boric acid in the mix?
3. Does surplus of formaldehyde affect somehow the development process? I ask because by paraformadehyde is not dry, it is more like a paste and I could not measure it exactly.
Thanks in advance for all suggestions
luben