Re: Cyanotype Redux
Brian - I'm intrigued by your lightbox that gives such short exposures for traditional cyanotype. My own (paper about 5 inches from a bank of 20-watt BL tubes) gives a PDN standard printing time of 21 minutes. It would be nice if it were less! Best wishes Henry On 3/3/08 17:45, "john@johnbrewerphotography.com" <john@johnbrewerphotography.com> wrote: > Hi Brian > > If not rod coating I use a brush similar to the Richeson ( a Da Vinci) and > have never had any problems. I do use a little tween and my favourite paper > is Aquarelle Arches hot pressed for cyanotypes. I have tried different > ratios of A and B but always revert back to the regular 1:1 mix. I have used > foam brushes in the past and not found it abrasive but I kept getting > streaks in the developed print. > > John. > > www.johnbrewerphotography.com > > -----Original Message----- > From: Brian Pawlowski [mailto:beepy@netapp.com] > Sent: 03 March 2008 17:31 > To: alt-photo-process-l@usask.ca > Subject: Cyanotype Redux > > It can't POSSIBLY be this... > > I mentioned a while back problems with runoff with Cyanotype. I've > tried a few papers over a long time - and was finally trying Crane's > Weston Diploma Parchment. > > I kept getting a lot of run off and bleeding into highlights. I did > get a PH meter after someone commented on Bay Area water (mine reads > about 8.3) - so I consistently acidify (very very dilute hydrochloric > acid - pool chemistry - cheap). I follow Sam Wang's advice through Mark > Nelson to clear inverted. I am using Classic Cyanotype - went from 1:1 > Solution A to Solution B to 3:2 - but then as my highlight bleeding > problems plagued me I went back 1:1 (and with a new UV box my exposures > are 1m 50s even at 1:1). > > But Judy Seigel sent me a note along the lines of "This is a really > simple process. Why are you using a hake brush - use a foam brush. > Etc." > > I went to Home Depot, and picked up a couple cheap black foam > brushes with wooden handles. After several back and forth > tests, I'm concluding the foam brush outperforms the hake and > Richeson brushes for my cyanotypes - I'm getting virtually *no* > runoff - whereas before it looked like a Smurf took a bath in > the tray. > > Can it *really* be that simple? The foam brush moves more roughly > across the paper surface. Kevin Sullivan in an e-mail sometime back > when I made a comment about runoff on COT 320 said it might be > necessary to rough up the surface (to break the sizing?) on very smooth > papers like COT 320. > > Anybody want to weigh in on this? I've been mostly running calibration > sheets (step tablets for PDN work). I'll probably do a few prints > later. > > My only concern is that the foam brush will abrade the surface of the > paper too much with resulting loss of image detail (on the other hand - > cyanotype running off willy nilly and bleeding into highlights suck). > > > >
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