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  #11  
Old 1st March 2018, 01:14 PM
Terry S Terry S is offline
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Originally Posted by Mike O'Pray View Post
1. A pity that the before and after cards can't be shown as this might help me to decide about trying it.

2. Secondly half a teaspoon in 200 mls sounds quite strong but clearly you were able to stop the action quickly once you got to where you wanted to be.

3. Was it an immediate dunk in stronger than normal fix or just normal fix? Crucially can you wait and only dunk when what you see in the pot ferri solution is what you want or do you have to "predict" where it will be in say X secs so the fix is given the time it needs to work?

4. In theory over exposing and bleaching back should produce no better an effect that getting the exposure right, shouldn't it? However in practice it may in fact be easier to get the same of slightly better effect from this than attempting the "perfect exposure" I just don't know.

1. (cont;d) For instructional purposes I'd love to see 3 prints, namely, 1. the overexposed;2. the bleached back and 3. the correct exposure to compare and contrast.

Mike
Hi Mike and all.

Quite a few questions there Mike, but I'll have a go at answering each one.

1. After a couple of weeks, to let the prints sent get received by the recipients, I'll scan and put some prints for comparison at the end of these posts. Hopefully my scanning will be good enough to show the effects, but as we all know, what looks good on my monitor, (which is calibrated by a Pantone Huey btw) may look totally different on others monitors.

2. I have no idea what sounds strong or not, as various chemicals are used at various amounts in different formulas, but I was very happy to find the 'easy way' to make some Pot Ferri up. I preferred this rather than ending up with litres of the stuff and this can be stored and reused for a while at least. Using half a teaspoon of Pot Ferri in 200 mls was a nice easy way to mix some up and I didn't have any trouble controlling its action. It was also just the right amount to put some postcards in (doing them all individually), using a 7 x 5 inch tray. When I thought a now bleached print looked right, I whipped it out as quick as i could and put in in a tray of water and agitated for about another 30 seconds and the prints came out fine. There might have been a very slight difference between the various prints at the end after drying, with some having an extra second or so in the solution, but nothing was noticeable to my eyes. And I presume one could dilute the solution with a bit more water for slower action but I was able to use it with no problems at this dilution.

3. As for re-fixing, directly after the rinse, I put the prints in a freshly made solution of plain Hypo. Again a small amount was made and put in a 7 x 5 inch tray. I believe Hypo is recommended as it doesn't have a bleaching effect, which the faster fixes might have on something that has just been bleached in Pot Ferri.

4. In theory, yes, over exposing and bleaching back should produce no better an effect that getting the exposure right, but as said that's in theory and theories do not always seem to follow through. The only way to tell, for me anyway, is to look at prints, side by side, after I have done another print as before but with slightly less exposure. I will then compare the two or three prints together. Whether one process is easier than the other is open to debate and I'm sure some would prefer one process over the other.

I hope I have answered all of your questions.

Terry S
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  #12  
Old 1st March 2018, 01:28 PM
Terry S Terry S is offline
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...I forgot to add where I got the chemicals from.

Some time ago I made a big order with Silverprint and got the chemicals then as they were the cheapest that I could find in smaller amounts, when including the overall postage to be added.

Having just looked, Silverprint are still the cheapest FOR POT FERRI at least, BUT there is postage to be added.

When ever I buy any chemicals now, I always compare Silverprint with ebay.co.uk and often find a Polish supplier is cheaper, especially when adding the postage on top, it still works out much cheaper than a Silverprint order plus postage for one or two items.

Eg, just now 100g of Pot Ferri on ebay.co.uk, with the button, include the EU, in the search, for a 100g is £9.99 including postage from Essex.

Silverprint on the other hand is £6.72 BUT if ordered alone, one has to add £4.50 for carriage up to 2kg, making it £11.22; so the choice is yours as they say.

So, you really need to shop around and compare but usually for one or two items I use ebay.

Terry S
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  #13  
Old 1st March 2018, 05:12 PM
Mike O'Pray Mike O'Pray is offline
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Thanks Terry for that comprehensive reply. It goes to show how my impressions in this based on nothing more than a "feeling" were wrong I'd have thought that a lot more than 200mls were needed for even postcard size and that half a teaspoon in 200mls made it quite strong. My use of the word "strong" here is wrong. What counts is "controllable" and quite clearly it is.

Mike
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  #14  
Old 1st March 2018, 05:28 PM
Mike O'Pray Mike O'Pray is offline
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Since replying to Terry, I realise there was one more question I need to ask and is addressed to all who know about such things. Is it actually the case that after using pot ferri and to avoid any further bleaching effect, hypo as opposed to Rapid Fixer has to be used?

I ask simply because I never use hypo and if I can avoid stocking an extra chemical then all the better.

Thanks

Mike
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  #15  
Old 2nd March 2018, 12:18 PM
Terry S Terry S is offline
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I too would like a comprehensive answer to this question Mike, for I have only followed what is written in books and all of the ones I have read, say to use Hypo rather than a modern faster and stronger fixer.

Does anyone have a link to anything that says otherwise?

Terry S
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  #16  
Old 2nd March 2018, 01:30 PM
Terry S Terry S is offline
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Having just read a thread on another forum, one user says, 'It's not a good idea to use modern rapid fixer as that makes reduction very much faster and less controllable.' As well as this it is mentioned that modern fixers restart the bleaching process, when you actually want it to stop.

I haven't found anything in print to offer yet, so we can only take the above comments as written, but to me they both make sense.

Maybe it's another little experiment I will have to look into doing when the snow clears and I can get to the darkroom at the end of my garden?

Terry S
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  #17  
Old 3rd March 2018, 02:27 PM
Terry S Terry S is offline
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Quote:
Originally Posted by Mike O'Pray View Post
Secondly half a teaspoon in 200 mls sounds quite strong but clearly you were able to stop the action quickly once you got to where you wanted to be.

Mike
EDIT: It seems you were correct in your thoughts Mike.

Something made me look at my measuring spoons again last night as something didn't click quite right in my thoughts. So, back to skimming through The Darkroom Cookbook, to find my original source. Luckily I have dozens of post-it-notes on various pages for things that are relevant to me.

And there we have it at the bottom of page 303:

'Alternately, dissolve approximately 1/4 (!!) teaspoon of ferricyanide in 200ml of water.'

So there we have it, it is 1/4 and NOT 1/2 teaspoon as I first wrote.

Apologies to anyone who might have followed the first post, although if your reactions are were quick enough you might have been fine.

Terry S

Last edited by Terry S; 3rd March 2018 at 02:52 PM.
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  #18  
Old 21st March 2018, 07:44 AM
JOReynolds JOReynolds is offline
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I was taught to use plain hypo, not acid fix, with Ferri. If it is intended to use Farmer's, use non-hardening fix. Farmer's reducer is ferricyanide and hypo mixed. If there is sufficient density ferri can be used to increase highlight contrast but there is a risk of long-term brown/purple staining, more noticeable when used locally. Quite a few archival collections have prints that show this, especially those behind glass.
I used to see Farmer's used on cotton swabs and on areas masked with rubber solution (Cow gum).
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  #19  
Old 21st March 2018, 01:00 PM
Terry S Terry S is offline
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Having now done various tests, I can agree with you JOReynolds. A couple of prints that I purposely overexposed by two stops and then bleached back, already have yellowy brown staining. It was a bit worse before putting through the hypo, which reduced the stain colour, but it's still very noticeable.

I'm feeling a bit under the weather at the moment, but hopefully will scan in some test pictures to show what I'm talking about soon.

Terry S
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  #20  
Old 21st March 2018, 05:26 PM
Mike O'Pray Mike O'Pray is offline
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Jo and Terry, your last two posts have sounded alarm bells for me. It sounds as if there is no way to stop the staining? If you are getting yellowy brown staining on prints already, this is worrying assuming that nothing went wrong in the process.

Mike
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