Joe experiments with the citric acid / hydrogen peroxide reversal process for both still-life and daylight exposures, using his 8x10 sliding box camera. More details of the process: joevancleave.b...
Hi Joe. In order to try to maximize the white intensity of the highlights, I suggest to make an exposure strip and take note of the amount of light needed to achieve the full black tone of the second exposure. In my experiments with this reversal process, the overall balance of the image (midtown, blacks and highlights) was substantially influenced by the amount of light given in the second exposure. In comparative tests, going progressively darker on the second exposure, I witnessed the second exposure "eat" the lighter part of the image. Ideally I would give it just the right amount of light to achieve the full black tone, but I ended up actually doubling that amount to make sure that a full black was actually achieved.
There may be other factors that make a difference in our setups, but I suggest you to try fine tune and quantify the second exposure and see if that makes a difference. Keep up the good work Joe!
Hi Joe. Alway appreciate these videos. I must admit I couldn't get the bleaching right when I tried it with Ilford multigrade. BTW: Ansel Adams says in "The Camera" that he could manage exposures of 1/4 second without a shutter - but with practice! So maybe a training regime 😉 Your 8x10 camera looks great. Are the plans openly available?
I like your idea of a training regime, involving taking as many 8x10 images as I can! Regarding the camera, Ethan Moses of Cameradactyl Cameras has plans for the box camera project.
The brown/copper tones remind me of silver-chloride salt prints. Could the citric and peroxide reactions result in a form of POP? Do you know the silver salts used in the paper emulsion? {Bromide, Chloride, Iodide?} Maybe try and use some weak fixer on a test exposure to see of it goes away. Really enjoying the channel, thanks for making it.
It also reminds me the tone of NaCl salt prints. But the usual papers have a chloro-bromide emulsion, the matter becomes more complicated. Really interesting process to explore, thanks.
Have enjoyed this series do far. I have not tried this yet but will soon. So I have a few questions/thoughts. If doing a negative in the zone process you expose for the shadow and develop for the highlights. Would this be just the opposite. Also if you had a second developer with a little potassium bromide or similar restrainer would that work for the highlights. Again I have not tried this yet.
Great video joe, but I wanted to ask you since the last video, what hydrogen peroxide do you use? I tried your very same process but I couldn’t bleach my copy, I used grosery store hydrogen peroxide
It has to be stronger than grocery store peroxide. I get 35% food grade peroxide at a health food store that sells it for peroxide therapy. You can also get peroxide from beauty supply stores, but be sure you get the liquid, not the "creme" version, which is more like hair conditioner.
Can you use this reversal process to make enlarged negatives for hand coated processes? How well would it work to make an 8x10 neg from a 6x6 or 35mm in an enlarger?
I have a smith corona manual typewriter from the 1940’s and wondered if you knew any ways to do a little bit of cleaning without taking it apart? Thanks
You can do some cleaning of the segment area (in the slots where the type bars move). And depending on the Corona model, many had the underneath side open for access as well.
I have the one rotary shutter I've built, but it has a narrow range of speeds, due to its crude design. For the reversal process I'd need a shutter with a wide range of speeds, from 1 second down to about 1/100. Sounds like an electronically controlled shutter would be more appropriate.
