Just something I like to do when after a printing session I have prints which could benefit for a little (or more) punch (contrast)..partial bleach in either a sepia bleach of a Copper bleach and redevelop in FSA toner; gives a considerable boost, but obviously also a colour change..
Best,
Cor
I did a Google search for FSA toner and from another thread you made actually saw that it was thiourea dioxide - I have some thiourea here, what else do you need to make it?
Also, that post reminded me about the Toning Book and the author, Tim Rudman. I knew there was something out there like that. However, anyone have any suggestions on a source for one not $150-200 like advertised on Amazon???
NotedOriginally Posted by agregov
Thank you
Hmm, I assumed the recipe and procedures are soemwhere on the WWW..but it seesm not that easy: I got my first info on the toner from:'The best kept toner secret' by Tony McLean in the then Photon magazine. I contacted him directly. Later I bought Tim Rudman his book, but not at that premium..! I assume I cannot share from that book, perhaps you can try to contact Tony (from Darlington),
Good luck !
Cor
Copyright-wise, I believe the issue is whether or not Rudman (or someone else) has a patent on the formula. If he is publishing the formula found freely elsewhere then you should be able to share it here. Perhaps this is a good discussion topic for elsewhere.
Ok, I tried to contact Tony McLean, but his mail is not working (last contact with him was in 2000 perhaps no surprise). I am taking the liberty here to post his article here from Photon 'The best kept toner secret' by Tony McLean, from conversations with him I deduce that he is all in for sharing...
Thiourea dioxide, also known as formamidine sulphinic acid (FSA for
short) is a common chemical used in the textile industry as a bleach in the dyeing process. It has replaced the more toxic hypochlorites, as it is safer and does less damage to the environment.
The process is simple and the chemistry relatively safe. In fact thiourea dioxide is much safer than its chemical cousin, thiourea (as used in odourless sepia toning kits), which is a suspected carcinogen. The technique is applicable to both resin coated and fibre based prints and, because the result is a print which is composed of just colloidal silver, the image can be subsequently toned or returned to its original state. One major advantage of FSA over the usual bleach and tone formulae is that there is no loss of image density, if used with the correct beach. In fact, there is an intensification of the shadow tones with no loss of highlight density.
FSA is a powerful reducing agent whose application to monochrome printing was discovered by George Wakefield a couple of decades ago. When mixed in solution with an alkali, it will reduce the rehalogenized image back to metallic silver with variable particle size, and therefore colour.
FSA can be purchased here in the U.K. as a raw chemical, from Rayco and Silverprint, and in kit form from Silverprint (made by Speedibrews). The use of this substance is still very much underrated, and its potential still largely unexplored. The effects one can achieve can vary between subtle blue greys to, at the other end of the scale, over the top vivid colours. The choice is yours.
There are three main variables to consider in using this process.
These are the enlarging paper itself, the composition of the bleaching
(rehalogenizing) baths and the alkalinity of the FSA solution.
Generally, most enlarging papers purchased today are either chlorobromide (warm tone) or bromochloride which are more neutral in tone.
Yes, there will be readers among you who still have a box or two of gaslight papers or pure bromide papers secreted away, but they are in the minority. All papers that I have experimented with over the last couple of years have reacted positively to the process and I have not discovered any major difficulties with any of the common multigrade papers available today.
The elemental silver of a developed and fixed print can be converted to either one of three silver halides dependent on the type of bleach used. Silver bromide, chloride or iodide. Of course, the bleaching process does not have to be taken to its final conclusion and some of the original image silver can be left unaltered. This is yet another variable to exercise. In fact, I usually make up my bromide bleach deliberately weak to allow me the choice of full or partial rehalogenization. The bleaches can be stored in light proof, labelled containers but I cannot vouch for their shelf life. I prefer to make up fresh for each session.
In order for the FSA to become an effective reducing agent, an alkali must be added to the solution. The pH of the alkali determines the efficiency, or reduction potential of the FSA solution. The higher the pH, the quicker the reduction takes place, and the cooler the print tones. I prefer a slower acting solution with consequently warmer tones (smaller colloidal silver) and therefore use the lower pH alkali, sodium carbonate.
However, if you wish a colder, more blue-black image, then substitute the same quantity of sodium carbonate with sodium hydroxide.
I have found that a print of about one third of a stop lighter, together with a reduction in contrast of one grade, is a good starting point. Stop and fix as normal in a non hardening fixer and wash RC prints for 10 minutes and hypo clear FB prints and wash for a minimum of 30 minutes.
Beware, any residual fixer left in the print will combine with the bleaching bath and lead to a reduction of highlight density. To achieve an even reduction in the bleaching solution, dry prints must be presoaked and agitated constantly in the bleach.
Bleaching
(Rehalogenization)
The three bleaches listed below will convert the original silver image into silver bromide, silver chloride, and silver iodide respectively:-
Bromide bleach
Potassium ferricyanide l0 g
Potassium bromide 5 g
Water to make 500ml
Chloride bleach
Copper sulphate 25g
Sulphuric acid 10% 30 ml
Sodium chloride 25g
Water to make 500 ml
Iodide bleach
Potassium iodide 9.3g
Potassium ferricyanide 17.5g
Water to make 5OOmI
Prints should be bleached in subdued lighting, however, safe light conditions are not required. Ordinary tungsten lighting is appropriate, except when using the chloride bleach with chlorobromide papers. In this instance, both the bleaching stage, and the redevelopment should then be done under normal safelight conditions. Prints rehalogenized in the iodide bleach will reverse in tone and the borders and highlights will stain a brown colour. Do not be concerned, the staining will clear immediately on immersion in the FSA solution. However, I would recommend that a separate FSA solution for prints bleached back in iodide, as residual iodide in the FSA solution can lead to density loss in subsequent prints.
Preparing the FSA
FSA or thiourea dioxide is a fine white crystalline powder. It is irritating to both the skin and the respiratory system and should be stored in a cool place. Its reduction properties are non existent until mixed with an alkali, and the solution MUST be matured for at least one hour before use. If the FSA solution is matured for longer than two hours, a warmer tone will result. The solution does not keep well and exhausts pretty quickly so do not make up more than you need for one session. When mature, the solution has a faint sulphurous, biscuity (cookie) odour. I find it more productive to make up one litre of the solution and use 300ml at a time, replacing it after each lOx 8 print or equivalent. In an emergency, e.g. half way through redeveloping a print, the solution can sometimes be reactivated with the addition of a couple of grammes of sodium carbonate or a few millilitres of stock developer.
FSA solution
Thiourea dioxide lOg
Sodium carbonate lOg
Water to make 6OOmI
(Note: mature solution for a minimum of one hour before use)
After the print has been bleached, the print is washed for the appropriate time. Two minutes for RC papers and about 5 minutes for FB papers. Position the tray containing the bleach adjacent to your wash bath so that you do not contaminate the FSA with drips from the bleached print.
Bromide bleach with FSA
Full redevelopment will give you rich red brown shadow tones with pale grey-blue highlights. However, the image can be retrieved from the developer at any point giving a split-tone effect, with chestnut shadows and blue mid-tones, which will subsequently turn a yellow-green on drying.
It would be advisable to re-fix a print which has only been partly redeveloped.
Copper bleach with FSA
Chestnut shadows with grey-blue mid tones and highlights if only partly redeveloped. Full redevelopment will give neutral shadow tones with yellow-green mid tones on drying. With chlorobromide fibre prints, a neutral to blue-black tone is achieved depending on the alkalinity of the FSA.
Iodine bleach with FSA
The iodine stain from the bleach will disappear on immersion into the FSA.
However, it is probably best to wash the print for 10 minutes in order to remove the majority of the iodine. The shadow tones will then appear as a bright yellow (silver iodide) and will gradually turn pink, then red over a period of about 15 minutes. The re-development after an iodine bleach is much slower than either of the other two bleaches, just the thing for Lith printers taking a Sabbatical! It may take an hour or two to fully develop.
Although silver iodide is light sensitive, it is much less so when 'imprisoned' in its gelatin matrix, and I have not found any deterioration in the colours of prints made this way ....as yet. There is a substantial loss of highlight detail if the print redevelopment is curtailed at the yellow, silver iodide stage. It would therefore be advisable to adjust the contrast of the original print to compensate.
Like most things in life, the novelty factor of printing bright, multicoloured images on RC paper soon begins to pale. However, don't be disheartened... just try this redevelopment technique on a matte fibre based paper, perhaps using only partial bleaching, and your prints will be revitalised. I promise! Subtle pinks, blues and greens; a whole new paint-box is waiting to be used. Why not give it a try?
I'm with Bruce on this. A little RST cleans the green. Interesting thread on APUG (as was) on RST on the role of Sod.Sulphide..
Cor, thank you very much for posting this. With Thanksgiving and a lot of other stuff going on I just now have had a chance to look at it.
The funny thing is, when I first searched up FSA and found that it was thiourea dioxide, I figured it was basically thiourea and some sort of alkali. Some time ago I was experimenting with such for positive development of black and white films. I had actually deduced some months ago that I could use that chemistry to redevelop paper after reduction and bought a variety of reducers, but I hadn't gotten around to trying it out. So, time to get into the darkroom...
Since this thread is about Ilford Galerie, I have to mention that my first try with thiorea dioxide, which from now on I'm going to abbreviate as ThO₂, has produced beautiful chocolate brown tones. Very interesting! And easy to make. Bleached with Farmers Reducer.
Shadow density and contrast doesn't appear to have changed much, which is unfortunate as that's what I was hoping to achieve, but I'll have to look closer after drying.
Edit - not exactly color correct due to lighting but you get the idea:
Back to 130. It seems to give slightly cooler tones at somewhat elevated temperature. I presume that makes the hydroqinone more active in relation to the other ingredients. I prefer to work that way rather than upping the amt of hydroquinone in the initial mix, since I might print different types of paper in the same session.
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