RE: Cyanotype blotches

FWIW,

* You may try to increase the amnt. of clearing agent: I use 2 drops of
40% citric acid per ml of Cyanotype II sensitizer in the coating soln.
* Have you tried to use another paper? That way you can check if the
problem is due to the paper you're using.
* Do you use tap water to rinse the coating apparatus? Maybe there's
iron in your tap water, use drinking water without iron to rinse your
brush/coating rod ect.

Regards,
Loris.

> -----Original Message-----
> From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca]
> Sent: Thursday, February 17, 2005 7:22 AM
> To: alt-photo-process-l@sask.usask.ca
> Subject: Cyanotype blotches
>
>
> ...
> First, I noticed 5-10mm blotches all
> over the papers like salt sprinkles. The Beinfang's blue was
> OK (not as nice as the initial test) but the sensitiser
> practically fell off the Rives BFK paper during the wash
> rinse -- today using a kodak siphon tray running slooowly. I
> use a 10ml syringe fitted with an extension tube to draw my
> cyano solution from it's bottle and a separate dedicated eye
> dropper for adding the clearing agent. I drew 2ml of
> sensitiser and used one drop of clearing agent. It's possible
> that there were water droplets in the syringe from being
> cleaned after the first use, or possibly water in the sponge
> coating brush which I also cleaned with water yesterday. What
> other sources of contamination are common in this process?
> Could heat from the print dryer cause problems? 125F doesn't
> seem very hot. BTW the blotches were first evident after the
> initial coating of sensitiser had dried and I examined the
> paper coming out of the dryer, I thought maybe they would go
> away but development made the problem quite obvious. Also on
> the second test I "worked" the brush a little longer and
> harder into the paper probably making at least 4 or 5 passes
> to ensure the sensitiser was "in" the paper.
> ...
Received on Thu Feb 17 02:02:58 2005