Local bleaching of prints
I am trying to figure out how to bleach a small area of a print. There is an area of clouds in one of my prints that just seems too dark and out of place.
I have some potassium ferricyanide salt from the Photographer's Formulary cyanotype kit. I could mix that up. But then I need to figure out what strength to use.
At that point, as I understand it, I could paint it lightly on the area in question after it is fixed, right?
I also have the liquid cyanotype kit with solutions A and B -- is one of those potassium ferricyanide?
If you have potassium ferricyanide, that is all you really need. Actual farmers reducer also has potassium bromide as well. But it's ok. I usually take 6oz of warm water (while the print is still in the fixer, or in a water holding bath) and add 1/4 of a teaspoon of potassium ferricyanide to solution and stir. Then I test the strength of the bleach on a test print. If too weak, I'll add just a tad more potassium ferricyanide.
Tips for bleaching: Blow off the areas (yes, with your mouth) that you're going to bleach before bleaching, this stops the bleach from running into other areas. Other squeegee their prints. Have running water ready to stop bleaching as soon as you see a change, or quickly re-immerse in fixer. Be careful not to go too far, cause you can't reverse the process once you've gone too far.
In the case of the clouds in your print, once you've found a strength of bleach that you like, I'd use a cotton ball to apply the bleach to an area like a cloud.
Good luck and keep us updated on the results!
pot.ferricyanide works faster (or at least the effects are visible faster) in light areas of the print than in the dark areas. --therefor: increases local contrast.
bleaching a light area in front of a dark background is usually very easy to to. but lightening an dark area before a light background can be very tricky; one has to be super-careful not to spill any of the pot.ferri solution on the light area, because it would be visible instantly.
That's very helpful, thanks a lot for your help.
I could pick up some Farmer's Reducer, they have it on the shelf at Calumet here. How would that differ in terms of the local contrast effect?
I use a selection of Chinese calligraphy brushes and have a little hose with running water going. As I bleach the area, I apply water to the area below to keep the bleach from running. Use the running water to stop the bleaching action..it can go fast. This is the Bruce Barnbaum method, he is a master of local bleaching...EC
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
I do everything that EC does, but I place the print onto a sheet of glass and lean it on the sink wall at about 60 degree angle, that way the print is stable and you have no problems with the print being strained or even damaged, by being handled continuously by gloved hands.
Another vote for Mick and EC's method - I do the same - works well with the hose running under.
Hey Evan, where'd you learn that technique?
Mix the bleach until you get a (no kidding) weak pee color. It's better to have a slower working bleach, since it's much easier to control.
When the print comes out of the fix, rinse off the print, then squeegee it. Rinsing the fix off will help soften the edge where you're bleaching. If you don't rinse the fix off, the bleach can work too fast, which will leave a sharp edge. In other words, you'll be able to see where you've bleached.
I've never used cotton balls - I always use brushes, and place the print on a PVC sheet mounted on a stand in my sink. Light above, hose with running water handy. I always run water over the area directly below the area where I'm bleaching to prevent any 'bleach over'.
It was alluded to above, but I change the orientation of the print on the board so that a dark area is always below the area I'm bleaching (if possible). Then, if a bit of bleach runs off the area being bleached into a dark area, you won't see it since it takes much longer to affect a dark area.
Once you've bleached for a bit, return the print to the fix to neutralize the bleach. Then repeat the above steps until you're done. Generally speaking, it will take multiple applications - you don't want to throw the long bomb on the first play, since chances are, you'll bleach too far and ruin the print.
It's also important to understand that fix will accelerate the bleaching process - this is why you have to rinse the print off first - so you can control the process. However, it also means that when you return the print to the fix to stop the process, it can cause the bleaching process to proceed past the point where you bleached to. This is why you never bleach until it's 'right' - bleach a bit, return to the fix, and iterate. In effect, you want to 'sneak up' on it.
It can be a scary technique when you're bleaching a print that requires a bunch of manipulations under the enlarger, but once you've done it a few times, you'll have another valuable tool in your toolbox.
I learned this technique from Bruce Barnbaum - if you pick up his How-To book, a full description of how he bleaches is contained therein, along with a lot of other very useful information.
Shouldn't the print be re-fixed after the bleaching?
Ed Sukach, FFP.
I'm suprised no one has said that yet. Yes...the print should be re-fixed after bleaching.
Originally Posted by Ed Sukach
I use about 30ml of water in a little plastic cup. I put "a pinch" of pot. fero in it to start. If it's working to slow, I will increase it slightly.
The print is placed on a sheet of glass sitting upright in my sink. I use the hose and keep the water running dirrectly BELOW where I'm painting on the bleach to avoid any dripping. I also never let the bleach sit on one area for longer then a few seconds, as I find it will start to stain that area a color. This color is usually removed when re-fixed, but not always. If your doing alot of fixing on one image, I will often return to the fixer several times while bleaching.
Some papers bleach better then others. I'm using Kodak AZO and find it responds VERY well with no color stain. However, I've experimented with Ilford and a few other papers and had terrible results.
Good luck! This has been one of my secret tools in the darkroom for the past few years.