On Mon, 15 Aug 2005 18:32:06 +0000, jude.taylor@comcast.net said:
> Regarding the earlier post suggesting acids and their respective
> concentrations for pre-soaking paper for cyanotype and other processes,
> acetic acid wasn't mentioned. Is acetic acid in the form of white
> vinegar - grocery store brand - as effective as citric acid for a
> pre-soak?
I suggested acetic acid presoak as a better control to test hypotheses
as to why oxalic acid presoak is effective. If the mechanism is related
to pH shift, acetic acid would be also effective, but if the mechanism
is removal of ferric compounds as some people suggested, then acetic
acid would be ineffective. However, if there is no need to identify the
mechanism, citric acid is a superior agent for both modes of action.
Also, in the current discussion in general, I see the air that people
assume whether black specks appear or not in a particular brand of paper
is determined by the process during paper manufacturering. That is
certainly a possibility. However, there is a possibility that humidity
cycle is related to this. This is especially so when sparingly soluble
alkaline agent like calcium carbonate is used to alkalinize the paper.
Received on Mon Aug 15 12:50:42 2005
This archive was generated by hypermail 2.1.8 : 09/01/05-09:17:19 AM Z CST