Mottling in lighter tones in cyanotype?
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
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