im back at attempting to making direct postive reversals again.
there have been a number of different ways to do these over the years,
some use toxic chemistry ( sulfuric acid dichromate bleach ) some use a somewhat dangerous process
( wet plate ) and others are rather finicky ( silver gelatin ferrotypes ). there used to be a direct postive paper made by ilford
which was a single step, use normal photographic chemistry ( reglar old developer ) and it would develop a postive, instead of a negative,
these days when one says direct positive that is what comes to mind first … the good folks at galaxy have come up with their version of direct postive
( not sure what is in it, probably sulfuric acid ) i havne’t tried their chemistry yet but from what it seems in their website/video it seems pretty fun and easy.
there is another reversal process that uses permanganate instead of sulfuric acid …
i’ve tried a few of these processes .. the ilford paper is by far the easiest … the permanganate one worked OK but i messed up the PH of the clearing bath.
i love making silver gelatin tintypes, but it is a finicky process …
a few weeks ago ( maybe a month ago ) joe van cleave posted a video that was reposted on photrio.com ( neé apug ) that detailed
his experiments with a reveral process he discovered someplace online, and through conversations he had with the person who posted it.
the process uses hydrogen peroxide and citric acid as a bleach, no clearing bath and if you go to joe’s website ( strongly recommend lots of fun stuff there ..
he is a paper negative artist, afghan camera user and an avid typist ! ) you will see his 3 videos and the images he has made with the process.
be advised he uses STRONG hydrogen peroxide, about 15%, which can be purchased at a variety of places,it is not the weaker less concentrated hydrogen peroxide
you might find at your local pharmacy. i am kind of a scardie-cat when it comes to concentrated chemistr. its not that i don’t have good lab-technique, or
a rubber apron, gloves or a respirator, its just that if i can get away WITHOUT using peroxide that strong, i’d rather do that. it is one of my reasons
not currently doing wet plate photography … if i can do without collodion i am good with that, and if i DID do wet plate work, i would definately use
speed fixer instead of the traditional Potassium Cyanide.
so the other day i went to big lots and got a few cheap quarts of hydrogen peroxide ( 89¢ each ) and i headed over to whole foods
to get some citric acid. and i made a few exposures and attempts. first i was unsuccessful.
i was using coffee developer with a little d72 powder ( home mixed ) to boost the contrast and shorten development time. the negative looked great.
into the weak citric acid stop bath, short rinse with water too, and into the hydrogen peroxide ( about 1/2 cup ) and citric acid ( abou 1 tsp ) bleach ..
it is supposed to take about an hour but it didn’t do anything and by the end of it all, even after i waited a couple of hours, and then turned the lights on to fog the paper
( part of the process ) nothing happened.
i did a 2nd try, and still, it didn’t want to work.
so … i consulted someone who i knew would have a clue. he’s a photographer in california ned lewis, he’s a brilliant photographer a goes by the handle NedL ( on ipernety, photrio ).
i know he would know what was going on, he’s the guy who discovered how to fix lumen / retina/sun prints and he’s a paper negative artist who makes calotypes
( like the original fox talbot process ! )
has also been working the past week to get this 3% system to work, and he has had fantastic results.
he thought that maybe there was carry over from the sodium carbonate rich developer that was killing the bleach. makes sense to me. so, i changed my print developer
and mixed up some sprint print developer great developer, great chemistry, great folks !
and .. i exposed a 3rd paper negative and it worked great !, so i exposed another one.
instead of beng on a tiny scrap of paper stuffed in a 35mm camera, i put a 5×7 sheet into a graflex 3a and photographed the
dining room window. it took forever to bleach ( i had a 2nd 5×7 exposure n the same bleach bath ). 1 change of bleach, and about 6, maybe 8 ( i left and came back so i don’t
know exactly when it happened ) the paper negative was completely white, so i turned the lights on, fogged it and redeveloped it and it came out great. ( the 2nd one not so great bt that’s OK )
basically here is how it works:
you expose a paper negative and develop it in print developer,
you short stop bath it in a little bit of water and citric acid
and then put it in about 1/2 cup of 3% hydrogen peroxide with about a teaspoon of citric acid.
( there are actually gram measures and real volume measures he and joe use but im just tinkering to see if it works )
with joe’s recipe the print bleaches to white in a short amount of time, with NedL’s it takes about an hour, maybe a little longer.
after it is bleached so it looks like a white piece of paper you expose the print to light ( joe and ned both have the kind of light, time and filtration )
you redevelop in print developer, and it turns into a postive print .. stop and fix and there you have it !
stay tuned !