U of S | Mailing List Archive | alt-photo-process-l | Re: Mottling in lighter tones in cyanotype?

Re: Mottling in lighter tones in cyanotype?

Try another paper / another batch of the same paper... (COT 320 is
wonderful for instance.)

Optional: Also switch to New Cyanotype (it's much better in highlights
delicacy, but it's even more finicky with paper...)

10 minutes of air drying (at max.) is enough if you force dry the paper
later; you need the sensitizer in paper, you can start to blow hot air as
soon as the surface shine is gone...

Why are you diluting the sensitizer BTW?

22 Ocak 2009, Perşembe, 9:17 am tarihinde, Brian Pawlowski yazmış:
> Hi. Trying to work out a last kink in cyanotype.
> I am seeing mottling in my mid and light tones in both the image and an
> exposed Stouffer step tablet.
> I am using Arches Platine and a 1:1:2 Water:Sol'n A:Sol'n B cyanotype
> emulsion (20gm/100ml ferric ammonium citrate, 8gm/100ml potassium
> ferricyanide).
> The Arches Platine has minimal runoff in the (inverted) wash I use.  I
> am brush coating. I have rod coated also - but I seem to be seeing the
> mottling regardless.
> Ihave an exposure time to where I just merge the first two steps on a
> 31 step tablet.
> Roughly some things I've tried:
> 	acidified and straight from tap wash water (my tap is alkaline)
> 	Tween 20 10% and none whatsoever (one drop per 60 drops
> 	emulsion)
> 	Peroxide accelerate or not
> I was working on a very low key print earlier and I was not seeing
> mottling in the dark shadowed tones.
> But I'm struggling here wondering if something slightly odd is
> occurring suddenly.
> My prep area is about 65 deg. F and 50% humidity.
> I air dry the paper after coating for about one hour and use a hair
> dryer to make it bone dry before exposure (in a glass vacuum frame).
> Help!!!!!!!!!!!!!!!!!!!!!!!!!
> Brian