From: Monnoyer Philippe (monnoyer@imec.be)
Date: 07/26/02-07:21:47 AM Z
Sandy,
Too bad for the test. R&D is very often frustrating...
But if you want solutions for your contrast problem, you will find them.
Have fun.
Cheers,
Philippe
|-----Original Message-----
|From: Sandy King [mailto:sanking@clemson.edu]
|Sent: Friday, January 01, 1904 18:32
|To: alt-photo-process-l@skyway.usask.ca
|Subject: RE: Ferric citrate in VDB formulas
|
|
|
|The test with pure sodium ferric citrate did not turn out well. In
|the test a 10 minute exposure of the test wedge, when developed in
|water and then fixed, gave a very flat image. I consulted Steven's
|book on the kallitype and it appears to suggest that when using
|sodium ferric citrate as the sensitizer a developer other than water
|is required. Apparently Nichols experimented with SFC and in fact
|patented a kallitype procedure based on its use, called the K1 a
|process by Stevens.
|
|Sandy
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|>Philippe wrote:
|>
|>>
|>>I am pretty sure that only sodium citrate helped dissolving the
|>>ferric citrate.
|>>With the solution you are trying now (10g/10g), you will have
|>>mainly sodium ferric citrate in the solution + an exces of 1.67 g
|>>of pure ferric citrate.
|>> To have pure sodium ferric citrate, you should have added exactly
|>>12.01 g of sodium citrate (assuming the you have sodium citrate
|>>under the form tribasic, dihydrate).
|>
|>
|>Yes, you are right in that the sodium citrate by itself has
|>completely dissolved the ferric citrate. After seeing your message
|>above I went back and added an extra 3g of sodium citrate to the
|>solution (now 10g of ferric citrate + 13g of sodium citrate in 35ml
|>of water) and everything has now dissolved. I should be able to test
|>the solution very soon.
|>
|>Sandy
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|>--
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