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> eh_up from south yorkshire |
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eh_up from south yorkshire
Hi All,
this is great forum and I have learned a lot over the last few months through 'lurking'. However I would appreciate a little specific help. Although not new to the darkroom I have only used those at art college / university so have been used to chemicals on tap. A few months ago I set up my own studio/darkroom and realised I don't know how long working solutions last! Despite searching for info via google etc I still require help with the following: AGFA FIX Ag fixer & Rollei RPN print developer. I am currently printing about 20 - 8x10 prints per week. Can anyone tell me how long I should expect to continue to get good results with these chemicals before I need to make up new solutions? John |
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it varies depending on your particular developer which I don't know.
However there is a technique called Factorial developement: Using freshly mixed working strength developer, you place first print in the developer and time how long it takes for the image to start emerging. Then if developing to completion takes 2 minutes in total, you divide the 2 minutes (120 seconds) by the emergence time which gives you your factor. So if for example the emergence time was 20 seconds, then 120/20 = 6. Then for all subsequent prints in that working strength developer you time the emergence time and multiply by 6 to give the total time to leave the print in the developer. This gives consistent results as the developer is used up and becomes weaker. What you will find when the developer starts to become used up, is that the emergence time will start getting longer. When it becomes too long its telling you that your dev is approaching complete exhaustion and its time to mix up a fresh batch. The data sheet which comes with a box of paper should tell you the approx capacity of working strength developer. i.e. how many sheets of 8x10 it can develop in a litre of working strength or equivalent. Use that as a rough guide but manufacturers are quite conservative about how much it will develop and you can usually get more out of it, especially if you use factorial development to monitor it. edit: p.s. Richard makes some good point below. On a subsequent session if you find the emergence time has increased significantly between sessions, then it probably indicates your developer has oxidised in that time and should be changed. Last edited by Argentum; 27th November 2011 at 04:34 PM. |
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Hi John and welcome to Fadu, as far as chemicals last it really depends on how much paper you use at any one time, whether you use RC paper or FB paper, but as a guide I would always mix developer fresh for every session, or, if you want to chance it you can sometimes get away with a second session if it is within a day or so, but if your printing sessions are a week or more apart then always mix fresh,and with FB paper then every session needs fresh developer, with fixer, if you are using RC paper, and up to 91/2x12 then I litre of fixer can be safely reused for a second session, as long as you are not using 20 0r 30 sheets per session, if you use a lot of paper then fresh fix is safer, it depends upon the amount of silver in the fixer, but if the session is 7 or 8 prints then you can use the fixer 2 or 3 times max. With FB paper then I would use thge 2 bath method, fix for 2 minutes in the first bath, then 2 minutes in the second, which is the fresh fix, and after perhaps 7 sheets though out the first bath and use the second bath and a new mix for the second, You can get fixer test kits from Fotospeed and tetenal, just look at the websites of AG or Silverprint.and they wil tell you exactly when your fixer is exhausted and needs replacing.
Sorry for the long winded explaination, but I hope it makes sense to you, Richard
__________________
jerseyinblackandwhite.blogspot.com |
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Peter Hogan, one of our friends here at FADU also sells fixer tester. It is well worth getting to test for paper and film processing and lasts a long time at two drops per test.
Mike Last edited by Dave miller; 28th November 2011 at 08:09 AM. Reason: Link added. |
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Welcome John
I dont think I can add to what the others have said. sounds all good to me.
__________________
Mitch http://photomi7ch.blogspot.com/ If you eliminate the impossible whatever remains no matter how improbable must be the truth. |
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Hi John,
There are actually two answers to your question! Non-archival processing - I just want a result The developer is usable until the images takes longer than 1 minute to appear (there is a wide variance between different papers as to when the image first appears in fresh developer - for example more than 20 seconds between Adox MCC fibre paper and Adox Fine Print Variable Classic fibre paper). The general capacity of fixer will be given by the manufacturer in terms of so many square metres of paper. However, you should note that this can vary greatly depending upon whether you prints have a lot of highlights or shadows. The fixer will still work with up to 3 - 4 grams per litre of residual silver. You can buy HT-2 testing kits from most photographic suppliers to monitor the residual silver levels. If you store the chemicals in tightly stoppered brown glass bottles between sessions this will extend the usable life of the chemicals. KEY POINT: Never ever skimp on washing your prints as this will contaminate you dryer with chemicals and, if you choose to do archival printing at any time, will contaminate everything that you produce. Archival processing The defining principle of archival printing is to tightly control all stages of the processing sequence to ensure that each stage is completed to achieve optimal results in terms of quality and the print's longevity. Key factors are that:
Hope this helps - it is basically do I want my photographs to last a long time? - archival processing required. Am I just learning? - so long as the chemical work be happy.
__________________
David, d.s.allen, fotograf dsallenberlin@gmail.com http://dsallen.carpentier-galerie.de |
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Quote:
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Thanks everyone for being kind enough to take the time to say hello and offer so much great advice. It all seems to flow together to provide the kind of help I needed just now while establishing my new darkroom practice.
Argentum: Factorial Developement is new to me - thanks. Richard: thanks for the specific sheet number examples. Mike: I will order some fixer tester from Peter. Mitch: Enjoyed looking at your blog. David: I had forgotten that we used archival processing at college when preparing work for exhibition/sale - thanks for that. Dave: I am currently using RC while I get into the swing of things with the chemistry. Thanks again guys. John. |
#9
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some RC papers have very fast emergence times, especially if they are developer incorporated papers. This can make using factorial development tricky. In that case just wing it like everyone else.
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#10
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You will find that developer will last longer with R/C papers because they have accelerators incorporated in their emulsions. They also need much less washing than fibre papers, typically around 1 to 2 minutes as well as drying quickly too.
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