Washaid concentrate life?

[Doremus Scudder]

I'm looking at my copy of C.E.K. Mees' Fundamentals of Photography, c.1935, he's writing about how easy it is to simply taste your prints to check for residual hypo.. Awesome!
Mike

Mike,

I'm interested in learning more about this. Would you mind posting the relevant passage from Mees for those of us who don't have ready access to the book?

TIA,

Doremus

 

[Gerald C Koch]

I'm looking at my copy of C.E.K. Mees' Fundamentals of Photography, c.1935, he's writing about how easy it is to simply taste your prints to check for residual hypo.. Awesome!
Mike

Not a particularly good idea as used fixer contains silver. This book was written when the toxicity of some substances was poorly understood. The buildup of silver in the body causes a condition called argyria. While silver is not particularly toxic as heavy metals go argyria causes the skin to turn blue. The amount needed to cause the condition is very small perhaps a few milligrams. The effect is cumulative and cannot be reversed. If you google on argyria you will find several sample photographs depicting the condition. Unless you want to look like one of the walking dead forget about tasting your prints.

 

[silveror0]

Hoffa,it's likely to be fine but you should get into the habit of mixing your own.HCA is the easiest darkroom chemical to make yourself. a formula is in he back of WBM.

Ralph, I checked out the formula in WBM2 and found that the sodium sulfite is mixed in 120F water; if only a little working solution (e.g., one liter) is needed for the session as a one-shot, how is it cooled for use short of stashing in a bucket of ice? How is that convenient? Is that high temp really needed for quickly dissolving?

 

[mshchem]

Mike,

I'm interested in learning more about this. Would you mind posting the relevant passage from Mees for those of us who don't have ready access to the book?

TIA,

Doremus

This comes up in a couple places in EKCo books from the 30's . I have a copy of Elementary Photographic Chemistry, EKCo. 1931 page 35. There is discussion about using hypo test solution etc. "An even simpler test is to taste the prints since hypo containing silver has a sweet taste"

Sounds a little looney to me. However back when you had to pump your own water this might have been a good trick with an experienced palate. I don't think I would try this with a print that had been fixed in a rapid fix with sulfuric acid added.

This is great source literature, they recommend cascade washing all good advice. This statement sums up the chapter on washing. "Six changes of water, allowing five minutes for each change, should be sufficient to eliminate the hypo effectively from any ordinary photographic material"

Pretty good advice as long as you rock the tray every minute or two.
Best Regards Mike

 

[mshchem]

Not a particularly good idea as used fixer contains silver. This book was written when the toxicity of some substances was poorly understood. The buildup of silver in the body causes a condition called argyria. While silver is not particularly toxic as heavy metals go argyria causes the skin to turn blue. The amount needed to cause the condition is very small perhaps a few milligrams. The effect is cumulative and cannot be reversed. If you google on argyria you will find several sample photographs depicting the condition. Unless you want to look like one of the walking dead forget about tasting your prints.

No argument on this point. Same era when the literature references cyanide as having the odor of bitter almonds. Yikes!
Best regards Mike

 

[mshchem]

Not a particularly good idea as used fixer contains silver. This book was written when the toxicity of some substances was poorly understood. The buildup of silver in the body causes a condition called argyria. While silver is not particularly toxic as heavy metals go argyria causes the skin to turn blue. The amount needed to cause the condition is very small perhaps a few milligrams. The effect is cumulative and cannot be reversed. If you google on argyria you will find several sample photographs depicting the condition. Unless you want to look like one of the walking dead forget about tasting your prints.

One thing to note, there are several appliance companies, and water purification pitchers that use ion exchange media to remove lead and some other heavy metals from drinking water. The mechanism is by exchanging silver ions for lead. NSF approved for lead removal
Best Regards Mike

 

[Gerald C Koch]

No argument on this point. Same era when the literature references cyanide as having the odor of bitter almonds. Yikes!
Best regards Mike

I can attest to the fact that hydrogen cyanide and its salts do have the odor of bitter almonds. For the reason why read the following very interesting article. You may never eat again after reading it. Despite their toxicity cyanides have many uses in chemistry.

http://www.foodsafety.govt.nz/elibrary/industry/Cyanogenic_Glycosides-Toxin_Which.pdf

 

[hoffy]

Hi Folks,
Another quick question. I managed to buy some Sodium Sulphite the other day. When I picked it up, I was told that once mixed, it oxidises rather quickly and it starts to lose its effectiveness in as short as one hour. Is this correct? I was told to mix 1 tbsp per litre.

 

[CMoore]

FWIW:
I can only give you the Opinion/Perspective of a complete beginner, but.....when i hear things like this, i always wonder what is meant by statements such as "starts to lose its effectiveness". Does that mean it is only 97% as good as it was, or 50%.?
Seeing as how a lot of guys use straight water, or no stop at all, i just figure i am way ahead, no matter if the chemical is 100% or 69% at days end.
No doubt the guys with the real answers will weigh in shortly.

 

[hoffy]

Thanks CMoore. I totally understand that, but I suppose if you wash, expecting a level of archivalness (is that a word?), but there is a step in the process that falls short, it's good to know at what point it is breaking down!

 

[CMoore]

No doubt.
I am talking about what "works".
You are discussing what works, to what degree, to a certain industry standard.
So you need the smart guys, and not me.

 

[hoffy]

Now now CMoore - as I kept on being told, don't underestimate your own contributions! I'm sure you are a smart guy!

 

[Gerald C Koch]

"Starts to lose its effectiveness" is one of those statements that one can drive a truck through. As a wash aid it should be effective for several days if not stored in an open tray. Once used it should be discarded as the used solution does grow mold.

 

[darkroommike]

I still have several bags of Kodak Hypo Clearing Agent, KHCA. I only use a wash aid when processing fiber prints, film and RC papers wash fine without. When I use this up I'll be mixing up a simple sulfite solution to use one-shot, one tray at a time.

 

[Gerald C Koch]

While the idea of just mixing up a simple sulfite solution to use as a wash aid is appealing if you live in an area with very hard water you may have a problem. This is because calcium will produce a cloudy solution containing calcium sulfite. This could leave a residue on the surface of prints. Should this happen then you will have to add a calcium chelating agent to the mix. Then too the solution should be slightly acidic and contain a buffering agent and voila you're mixing Kodak HCA.

 

[hoffy]

So, according to the water quality audit for my area, my water hardness is 92 mg/L, which from my research is slap bang in the middle of acceptable standards. I hope I should be OK without using Calgon on Sodium Metabisulphite

 

[john_s]

I don't know how to interpret 92mg/L but I was under the impression that Adelaide water had a significant amount of minerals compared to, say, here in Melbourne. It might be a good idea to get some sodium metabisulphite from a home brewing shop to be on the safe side. You only need a teaspoon of it per litre, and for a few dollars you will have a lifetime supply. Your water supply will be different in summer to winter. If you do a test now your results might be different during the next dry season.

I have also read (and I am definitely not an authority!) that Calgon in different markets or at different times is not always the same. I'm sorry to be vague, I just thought I should tell you.

 

[hoffy]

Thanks John,

The only reason I keep on mentioning Calgon is it was the product/chemical my folks used to use with their bore water (or well water for our American friends) on the farm. Now, that stuff was hard as the proverbial if you didn't use Calgon - soap never lathered at all, it used to produce a flakey scum on top of the water.

But, yes, I'll get some sodium metabisulphite.

 

[mshchem]

While the idea of just mixing up a simple sulfite solution to use as a wash aid is appealing if you live in an area with very hard water you may have a problem. This is because calcium will produce a cloudy solution containing calcium sulfite. This could leave a residue on the surface of prints. Should this happen then you will have to add a calcium chelating agent to the mix. Then too the solution should be slightly acidic and contain a buffering agent and voila you're mixing Kodak HCA.

I don't know what is the exact shelf life of Kodak HCA but I mix up the gallon concentrate and store in 1 qt. bottles. I dilute and use once and toss. I usually use RO water to mix as here in Iowa (I live in Coralville, i.e. bedrock is 99.9% Calcium Carbonate) water is HARD. I use HCA with fiberbase always. When I am printing with fiber or RC I go from fix into Selenium toner mixed into HCA. I use it with TMAX films to help remove the purple. Kodak HCA is cheap and easy. I've used it forever.
Best Regards, Mike

 

[Gerald C Koch]

Calgon (s0dium hexametaphosphate) is a polyphosphate that is it contains several phosphate groups. For many years it was used as a cheap water softener. However it does hydrolyze into simple phosphates and thus contributes to phosphate pollution of lakes and streams causing algae buildup. Because of this governments have tried to discourage its use. Fortunately for photo enthusiasts there are a couple of other phosphates that can be substituted for it. A calcium ion gets trapped inside the ring of phosphorous atoms as can be seen from the article below. Once inside it cannot cause trouble.

https://en.wikipedia.org/wiki/Sodium_hexametaphosphate

 

[darkroommike]

Thanks John,

The only reason I keep on mentioning Calgon is it was the product/chemical my folks used to use with their bore water (or well water for our American friends) on the farm. Now, that stuff was hard as the proverbial if you didn't use Calgon - soap never lathered at all, it used to produce a flakey scum on top of the water.

But, yes, I'll get some sodium metabisulphite.

My father was a well driller and I am a Certified Pool Operator, deep well water is usually hard but shallow domestic wells can be very soft. Soft water is good for soaping up but hard on copper pipes hard water causes soap scum and is bad for galvanized pipes. I should add that rain water (not acid rain!) is soft and the water captured from a dehumidifier is very neutral. My domestic water is fine with just a sulfite washaid but if you want to mix up a stock solution you need both sulfite and bisulfite and if your water is hard you will also need Calgon (the real stuff, sodium hexametaphosphate, not the stuff now sold in grocery stores).

 

[silveror0]

...Fortunately for photo enthusiasts there are a couple of other phosphates that can be substituted for it...

Gerald, would you please identify that couple? TIA

 

[Gerald C Koch]

Certainly. sodium tripolyphosphate and sodium tetraphosphate. Not quite as good as sodium hexametaphosphate but easier to obtain under today's restrictions. The Chemistry Store sells one of these but I don't remember which.

 

[darkroommike]

Certainly. sodium tripolyphosphate and sodium tetraphosphate. Not quite as good as sodium hexametaphosphate but easier to obtain under today's restrictions. The Chemistry Store sells one of these but I don't remember which.

I looked, The Chemistry Store sells Sodium Tripolyphosphate and Sodium Hexametaphosphate. The latter is much more expensive, minimum purchase for either is FIVE pounds.

 

[CMoore]

Ebay has it for 8-15 dollars/Pound with free shipping.

So, how important is this stuff.?
Or how accurate do you need to be.?
Can you just add a small teaspoon or less into your mix.?

My water is "hard". Where the sprinklers hit the fence (not that we water a lawn anymore) it bleaches and rots the wood.
Glass in the shower gets a film that is almost impossible to remove. Sink and shower fixtures do the same.
That said, the sink in my darkroom runs through a filter, but not sure if it filters That Stuff or not.