Fish and Chips

A classic dish in the UK is fish and chips. It is traditionally served with salt and vinegar (acetic acid). This has become the title for this post, as the bleach I intend to make is one I found on the Moersch Photochemie website, as it uses vinegar and salt. The formula is listed below.

Water approx. 50°C	750	ml
Potassium permanganate	6	g
Sodium chloride	13	g
Acetic acid 98%	50	ml
Water on	1000	ml

The appeal for me to try this bleach is the rehalation uses chloride not bromide. This may change the toning outcome from a bromide paper. 

(The term rehalation means to add a halogen ion to the silver ion. A halogen or halide is one of the group 17 in the periodic table that includes Fluorine, Chlorine, Bromine, Iodine and others. The term derives from Greek for 'salt producer' as it combines with alkali metals to form salts such as common table salt sodium chloride. Three of the halogens are the basis for silver-based film and papers, silver chloride, bromide, and iodide. When paper or film is exposed and developed the silver ion is reduced by the developer to make metallic silver Ag+ -> Ag. Bleaching converts the silver back to an ion Ag ->  Ag+ where it can be fixed away with fixer as with Farmers reducer. Or rehalated if bleached in the presence of a halogen ion. The most common bleach is Potassium Ferricyanide + Potassium Bromide which converts the metallic silver to silver bromide.) 

I got started on this track in an earlier session of lith printing where I picked up a suggestion to use Kosher salt in the lith developer itself. The results were not as expected but it got me thinking about chloride rehalation as an alternative to the normal potassium bromide formula. I started with a simple minded bleach using my existing potassium permanganate bleach and adding sea salt. 

The problem with this is the acid I use for this bleach is sulfuric acid. It is strong enough to cause the chlorine in the salt to be expelled as chlorine gas of which there is a faint smell.  In fact, mixing salt with sulfuric acid is one way of making chlorine gas. This means I am probably not getting much chlorine in the rehalation process. 

Fortunately I stumbled onto Wolfgang’s salt bleach formula. It uses acetic acid to activate the potassium permanganate bleach which is a weaker acid so it allows the H+ CL- to exist in solution. This means the Cl (Chlorine) ion stays in solution for rehalation of the bleached silver. 

To test this new bleach I started with an old lith print made on Oriental Seagull paper. One clever use of failed prints is to test bleaching and toning strategies before risking better prints. Here is one I made last year…

Original Test Lith Print
(Oriental Seagull Fotospeed Lith Developer)

I bleached this print. The bleach is extraordinarily strong as I mixed it and it took less than 60 seconds to bleach almost all the image away. Probably too much to be useful. In future I will dilute it. 

Photo of Bleached Print after Clearing Bath.

I took this bleached print, washed it, and placed it in a potassium metabisulphite clearing bath to remove the yellow stain from the paper.  I then redeveloped the print in the Moersch EasyLith developer. Slowly the image returned over many minutes. 

Photos of Development Progress.
(Not all these photos are very well exposed.)   

The shadows retained their cool black tone, but the highlights came back warmer than before. I did note in the prior post that EasyLith gives a slightly warmer tone than the Fotospeed lith developer. However, if I compare the bleached print with one of the earlier lith prints, the bleached print was a more intense pink color which I attribute currently to the chloride rehalation.  

Bleached and Redeveloped Version

For the next round of experiments I started with a dilution of the Fish and Chips bleach. The action was so fast on the original that it was difficult to control the depth of the bleach. So I have come to think of it as a stock solution and now mixed my first 'working' solution at 1+9 by taking 50ml of stock and 450ml water. This I put in a 1000ml bottle so I had room to dilute or concentrate it further. 

I took one of my Oriental seagull prints from my last lith session and bleached it in the working solution until the highlights were mostly gone. The bleach works on shadows rapidly as well. 

Bleached Fish and Chip 1+9

Then tried my Moersch MT7 Iron toner kit to tone it blue. I reasoned that if I mixed the Parts 1, 3, and 4 and skipped part 2 which is the Potferri bleach thinking since I had already bleached the print I wouldn't need more bleach. It seems however the iron toner needs a silver ion not a silver halide to work on. There was no hint of blue toning on the image until I relented and added the Potferri. I then got the following version where the existing silver was converted to blue. This meant it really needed the Potferri to breakdown the silver to silver ions that could then be toned. None of the bleached highlights turned up. 

Bleached and Iron Toned

Since this was not what I was after I decided to redevelop it in EasyLith developer. Since EasyLith is alkaline I knew I would lose the blue iron toning. Hopefully the highlights would return. Which they did. I then applied the blue toner.  

Blue Toned

A nicely blue toned version. I am not sure Fish and Chips made this any different form iron toning from the start but I learned something about bleaching and toning.

The second print was another of the same lit prints but this one I toned first in selenium toner 1+19 for 3 minutes. This should help me hold the shadows from the bleach and allow me to bleach the highlights more exclusively. I then bleached the highlights a redeveloped in EasyLith the highlights. The result is more neutral in tone. I am not sure the bleach had much effect here as it is more likely due to the Selenium. 

Selenium Toned Bleached Redeveloped

It is interesting that this process did show the fallacy of expecting archival qualities from a 1+19 selenium toning bath. Below is a photo of the print that had been bleached after a 3-minute bath in selenium toner. You can note that much of the untoned areas have been bleached away. 

Bleached Print after Selenium Toning

In the end I am not sure what if anything I have achieved.