RE: VDB metal bleed in water bath
Hi David, If your coating table is not level that will certainly lead to excessive coating in one part of the paper (and insufficent coating in the opposite part) - that was my point... 3ml per 11x14 looks like a good figure - of course, all depends on paper / emulsion though. (For instance, I use 2.3ml Ziatype coating solution on COT 320 for the same area.) Regards, Loris. -----Original Message----- From: david drake [mailto:daviddrakephoto@sympatico.ca] Sent: 26 Aralõk 2006 Salõ 17:38 To: alt-photo-process-l@usask.ca Subject: Re: VDB metal bleed in water bath thanks Loris, I don't think that excessive coating is my problem. IÊ was previously coating a 11x14 area with 1.8 ml sensitizer and getting bleeding. I've since increased to around 3 ml with much better dmax! However, the staining is still creeping in from the borders into the whites (it's fairly mild but shows in the whites).Ê Mabey, it's just a matter ofÊ getting the amount of sensitizer just right? But, I'm not left with giant puddles at the end of the coating runs (sometimes very small puddles).Ê I'm going to try the photoflo this week.Ê I did try pre-coating the paper with distilled water but by the second coat of sensitizer the paper was getting pretty bumpy for my puddle pusher. I'll stick with the humidifier. cheers and happy boxing day! david On 25-Dec-06, at 2:29 AM, Loris Medici wrote: Hi David, glad to hear that you're having better results. Indeed, use of excessive coating solution is one cause for bleeding. (Because the emulsion is not in the paper but on it and will slide off when you put the print in water.) I was using Ilfotol with Classic Cyanotypes (same sensitizer as Vandyke: Ammonium Iron(III) Citrate) a couple of years ago - amount was 1 to 4 drops per 10cc of sensitizer. (Don't add this in your stock sensitizer solution by extrapolating the figures!) You have to "experiment" to find the correct amount for your paper / working conditions. If you put a sheet of impermeable/airtight material (for instance a polyester sheet, a scrap piece of negative transparency material... ect.) under the paper, you'll end up sealing it by its two sides (negative in front, polyester sheet at the back). This won't totally prevent loosing moisture, but it will slow its pace considerably... Merry Christmas / Happy Holidays to all! Loris. -----Original Message----- From: david drake [mailto:daviddrakephoto@sympatico.ca]Ê; Sent: 24 Aralık 2006 Pazar 20:52 To: alt-photo-process-l@usask.ca Subject: Re: VDB metal bleed in water bath I've been really lucky lately, it's been mild here in toronto with above normal humidity. Before coating yesterday, I notice that my coating table was no longer level. This was probably the major culprit ( as I'm using a Puddle Pusher)! The prints turned out much more even with only minor staining (landscapes with paper white skies don't help). I will try your Everclear suggestion Sandy and order some Tween from B&S. Loris mentioned Photoflo in his post. Would this work just as well as Tween? How much would one use per ml of sensitizer? My coating room was just under 50% RH and exposure room was around 35%. So it wasn'tÊ outrageously dry. I just sealed my paper in a black plastic photo paper bag for transport between locations, to help keep in moisture. david drake photography www.daviddrakephotography.com
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