I certainly do remember the Rives BFK discussion. I was also under the
impression that this is a buffered paper. Since there were differing
opinions about this and because I am of a scientific orientation, I
decided to find out. Here is how I did it.
Sometimes when I am wearing my Archivist's hat I do a little demonstration
with acid-containing paper (e.g. that black, photo album paper). What I
do is soak said paper in distilled water then pour off the water into a
test tube and add a few drops of universal indicator. I get a nice red
color which indicates a low pH. I then test the distilled water and some
Permalife paper and get a yellow-green color which indicates a pH of
about 7.
After last year's discussion about BFK, I did the same thing with
it and it tested neutral (pH 7). After reading your recent post, I
decided to repeat this simple test since I just got a new shipment of
BFK. I must report that it again tested neutral. My conclusion is that
Rives BFK is NOT buffered and is therefore safe for cyanotype. Since last
year I have been using it a lot. My students have been using it with
good results, at least, good for students. I like it because of its
ease in coating. Anyway, whatever works.
Schramm prints WILL NOT FADE. Schramm will fade and may, in fact,
be fading already.
It is possible that at one time, there was a buffered BFK produced.
There are a lot of buffered products being made for archivists, but
I think that some manufacturers may be adding a buffer to their paper
to make up for the fact that it is crappy paper. Anyway, we have to
watch out for buffered storage folders and boxes and keep cyanotypes
out of them. If in doubt, test.
BTW, I also tested West Virginia tap water and, to my surprise, I
got a green color (mild base). I would have guessed acidic because we are
in a high acid rain locality. Know I am wondering if I should use
a weak acid rinse on my cyanotypes. Of course, as you pointed out,
I am useing an sensitizer with acid in it.
I posted all this to the list since I thought the results of my
tests would be interesting to others.
Bob Schramm