Re: Cyanotype

No white spots. Definately has more of a problem, or potential for problems,
with grain using the 40% solution. I'm going to do another set of tests to
be sure. I also noticed a bit of oxidation(dark edge line?) at the edges of
the emulsion. But with a good brush, coating technique and the right paper
it could be viable for those who currently double coat. Drying time was also
a tiny bit longer. The first test I did I souped it on pretty thick and the
test had trouble clearing in the highlights. The next tests I used a 1"
fine-haired watercolour brush to give just one or two passes and it fixed
that problem. The thing that impressed me the most was the dmax, it looked
like a double coat of my standard 1:1 mix. I'll try to scan the results
later and post them. I don't own a densitometer but my Ep3200 does an OK
job.

~m

----- Original Message -----
From: "Christina Z. Anderson" <zphoto@montana.net>
To: "Alt List" <alt-photo-process-L@usask.ca>
Sent: Thursday, February 16, 2006 8:18 AM
Subject: Re: Cyanotype

> Cool, Michael.
> Did you see any graininess or white spots in the 40% coat? What makes the
> 40% coat harder to coat?
> Is there any way you could post a jpg of the comparison of dmax of the
> three? Or do you have a reflection densitometer to measure the
differences?
>
> It seems you are saying that the only benefit to the 20% 2:1 is speed...
> Chris
> ----- Original Message -----
> From: "Michael Koch-Schulte" <mkochsch@shaw.ca>
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Wednesday, February 15, 2006 11:14 PM
> Subject: Re: Cyanotype
>
>
> >I mixed up the 40% and tried it:
> >
> > Single coats:
> > 40% "A" 1:1 Had best dmax, similar to double coating 20%.1:1 Needs a
> > defter
> > touch when coating. Definately could cause problems if overcoated. Not
for
> > wimps.
> > 20% "A" 1:1 Still had a deep blue, not as deep. Same number speed as
> > above.
> > 20% "A" 2:1 Lightest dmax but acceptable, Faster by about a stop though.
> >
> > ~m
> >
> >
> >
> >> Question: which leads back to Michael, I think, who asked instead of
> > using
> >> 20% FAC 2 parts to 8% potassium ferricyanide 1 part, why not mix a 40%
> >> solution of FAC and then use that 1:1 with an 8% solution of potassium
> >> ferricyanide...I wondered if mixing it up that heavily would lead to
> >> undissolved FAC in solution, if there is a point where FAC falls out of
> >> suspension....and then might lead to graininess or some such thing. You
> > say,
> >> below, you get crystallization on the paper--do you mean white spots,
> > actual
> >> crystals, graininess, etc??? Short of just mixing up a 40% and trying
it
> >> myself, which I might do, I'm just wondering if graininess that people
> >> complain about with the traditional formula has to do with too much
> > FAC...OR
> >> even, if the amount of FAC doesn't even matter that much as one person
> >> has
> >> suggested.
> >>
> >
> >
>
>
Received on Thu Feb 16 12:00:35 2006