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  #11  
Old 2nd March 2018, 10:23 AM
Richard Gould Richard Gould is offline
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Originally Posted by skellum View Post
Water has a limited capacity to hold dissolved material in solution. Distilled water comes with no 'preloading' of minerals in solution, so has more capacity to accept the chemistry we want to dissolve.
In areas of hard water (with more minerals to start with) you'll find it harder to fully dissolve thing like Hypo clear. I think it comes close to being a saturated solution- that is, at the limit of how much dissolved solid material the water is capable of holding.
The solution can sediment out and form crystals if it gets cold (reduced ability to hold material in solution) or sometimes just by standing stagnant.
I'm in a soft water area, so have little trouble dissolving chemistry, but even so I find Part B of my PMK sometimes drops a little bit of crystallised sediment. I warm it up, shake, and usually it redissolves.
We have very soft water down here, I have never hap problems mixing any chemistry, certainly Hypo clear always dissolve the powder, I can only think that it has been exceptionly cold here lately, below 0, which is most unusual, and the bottle is kept in my unheated darkroom, so maybe the cold has affected it, it is almost all gone so I will mix some new and store it in a corner of the lounge, somewhere out of sight
Richard
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  #12  
Old 2nd March 2018, 10:26 AM
jeztastic jeztastic is offline
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Hmmm. Sounds like a combination of cold and hard tap water. We are on the South Downs so lots of chalk and hard water.

So next question - mixing hypo clear in de-ionised water? Apparently it has a low pH. It is much cheaper than distilled water. Will it be OK for hypo clear?
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  #13  
Old 2nd March 2018, 11:29 AM
Richard Gould Richard Gould is offline
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It might be cheaper, in the long term, to get a water filter of some kind, maybe a Britta water filter?
Richard
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  #14  
Old 2nd March 2018, 11:50 AM
jeztastic jeztastic is offline
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Perhaps, but I've read that the carbon can escape into the water and cause spotting... We'll hang on, that would only matter for developers. Wouldn't make a difference to hypo-clear. Good suggestion.
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  #15  
Old 2nd March 2018, 12:26 PM
Richard Gould Richard Gould is offline
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Originally Posted by jeztastic View Post
Perhaps, but I've read that the carbon can escape into the water and cause spotting... We'll hang on, that would only matter for developers. Wouldn't make a difference to hypo-clear. Good suggestion.
One other suggestion is that when you defrost the freezer keep the melted ice water and use that for mixing, it is in effect distelled water,In the days before most car battery's were maintence free we would use the freezer water as distelled water to top up the battery, and I have used it to mix chemistry with no ill effects,and when I have had it for the final rinse again with no ill effects
Richard
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  #16  
Old 2nd March 2018, 12:54 PM
Terry S Terry S is offline
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I'd have to look it up, as I only use FB papers occasionally, but from memory, I read somewhere that if you mix your own, it's best to mix fresh each time. I don't remember a reason ever being given, but maybe what seems to be happening to peoples solutions, is the reason why?

It's something like a teaspoon of SS per one litre of water if I remember. It's also possible to use Sodium Carbonate (Washing Soda), which I used for decades and prints from the 1970's which were washed with this, still look good!

I'll have a browse of a couple of books soon and report back if I can find the info.

Terry S
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  #17  
Old 2nd March 2018, 01:21 PM
jeztastic jeztastic is offline
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Thanks Terry, that would be very helpful. A teaspoon at a time would suit much better. And washing soda would be cheaper still.
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  #18  
Old 2nd March 2018, 01:44 PM
Richard Gould Richard Gould is offline
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An old formula for Hypo clear is water at 30 750l
sodium sulphite 20
water to make 1000
use for one session and discard, mix fresh every time in effect water at 30 degrees, add 20 grams of sodium sulphite, which is around 1 desertspoon full disolve in the water then add another 250ml of water, use for session then discard, clearing time is around 2-3 minutes at 20 degrees
I used to use this formula and it worked, but it is now very hard to get the chemistry over here so I tend now to use Hypo clear bath from kodak.
Richard
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  #19  
Old 2nd March 2018, 04:33 PM
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Martin Aislabie Martin Aislabie is offline
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I only ever make up hypo clear as I need it.

A couple of spoonful's of sodium sulphite into 750 mL of tap water at 30 C and when its dissolved add cold tap water to make 1 L.

I throw it away at the end of a session.

Regarding de-ionised water, I buy 5 L from Halfords for £3.75 and it leaves almost no residue when it dries - its the nearest thing to distilled water I can find.

Martin
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  #20  
Old 3rd March 2018, 03:19 PM
Terry S Terry S is offline
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Just checking The Darkroom Cookbook, it seems Richard is about right with his 20 grams of Sodium Sulfite (or Sulphite) per litre of water, with the solution being discarded after use. As stated by a few, dissolve in 750ml of warm water and top up to one litre with cold water to bring to temperature.

The formula given in the book says for a stock solution, use 200 grams of Sodium Sulfite in one litre of water, which is then diluted at 1 + 9. This would equal 20 grams of SS in a litre of working solution. Just checking, and 20 grams of SS is two SLIGHTLY rounded teaspoons. I have a kitchen set of stainless steel spoons for accuracy, and they are kept with my chemicals and are used for this use only!

The freshly made one litre of solution can be used on up to 80 10x8 inch prints.

Terry S
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