Re: Toned cyanotype query
Hi Linda Whilst there are recipes around which use sulphuric acid as a cyanotype toner, I would be cautious about trying it as strong acids can cause the release of cyanide if there is any residual ferricyanide in the print. I would recommnend sticking to weaker acids such as tannic and gallic. Dave ----- Original Message ----- From: "Linda Stinchfield" <linda@turtlesilk.com> To: <alt-photo-process-l@usask.ca> Sent: Saturday, October 27, 2007 10:44 PM Subject: Re: Toned cyanotype query > Hi Chris, > > Thank you for your very helpful reply! I've done a little toning using > washing soda and tannic acid-- but hadn't figured out the general > alkaline/acid relationship. That gives me lots of new things to try! I > don't remember ever hearing of gallic acid, but apparently it's found in a > lot of plants that grow locally, so it should be easy to come by. > > One book I have recommends sulphuric acid for purples, but I don't have > any of that laying around the house! My husband has some muriatic acid and > I've been working up the nerve to try that... > > Thanks again, > Linda S. > > > > > On Oct 27, 2007, at 3:03 PM, Christina Z. Anderson wrote: > >> Hi Linda, >> Nice to see a "newbie" post for once on this quiet weekend!!! >> >> With toning cyanotype it is very easy: you use an alkaline to bleach the >> print, and then an acid to "redevelop" or tone. The alkaline can be TSP, >> sodium carbonate, ammonia, borax, sodium or potassium hydroxide, etc. >> Then the toning part is tannic or gallic acid and that from tea bags, the >> actual powdered form of tannic or gallic, walnuts, other nut hulls, etc. >> etc. >> >> There are myriad different formulae and recipes to get different colors >> from yellow to brown to purple to black to deep blue. >> >> Now, the question you ask is how to get eggplant tones--from my >> experience the more purplish tones come with ammonia as the alkaline and >> redeveloping in gallic. But that soooo depends, because you can actually >> tone first and THEN bleach, bleach partially and tone long, on and on. >> And each method has a characteristic color produced that can only be >> found by trial. >> >> If you have none of these chemicals except household stuff, try a test >> print of a brief ammonia bleach (partial bleach) and then tone in tea (1 >> bag per cup water). >> >> This'll get you started. Kai Hamann may still be on the list and he will >> give you OODLES of ideas, as are other people, too--Sam Wang, Judy >> Siegel, come to mind as having done a fair amount of toning of cyanotype. >> Jill Enfield and Christopher James' books have different colored toner >> formulae in them. How about googling the Metoyer guy and asking, too? >> If you do, report back to the list. >> >> Happy Hunting. >> Chris > > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: > 269.15.12/1096 - Release Date: 27/10/2007 11:02 > > ----------------------------------------- Email sent from www.virginmedia.com/email Virus-checked using McAfee(R) Software and scanned for spam |