Pure Hyo Sodium Thiosulfate - Like Zone VI Hypo Fixer

Going through my stash of darkroom chemicals today I discovered that I've run out of Zone VI Hypo (sodium thiosulfate) that I use for my 2nd fixer when processing FB paper prints. Since Zone VI/Calumet chemicals are long gone, I need to find a substitute.

Note: This is not the Zone VI Film & Print Fixer, it's their plain hypo fixer.



I don't mind mixing my own so I found a number of on-line vendors that sell sodium thiosulfate. The best price seems to be from ChemistryStore:

https://www.chemistrystore.com/Chemicals_S-Z-Sodium_Thiosulfate_Penta.html

It is in pentahydrate form.

I found a formula for making 'plain hypo fixer':

water 125 degrees F 750 ml
Sodium thiosulfate pentahydrate 250 g
Sodium sulfite anhydrous 30 g
Water to make 1000 ml

Questions:

1. Does anyone know if the Zone VI Hypo had sodium sulfite anhydrous mixed in or was it just sodium thiosulfate, ie 'pure hypo' ?

2. My understanding is that sodium sulfite is added to extend the life of the fixer by absorbing oxygen. Without it, how long should the plain hypo fixer last in a tray? Should I add it in anyway?

I've attempted to convert the formula to make a gallon of fixer at a time:

water 125 degrees F 85 oz
Sodium thiosulfate pentahydrate 946 g
Sodium sulfite anhydrous 114 g
Water to make 128 oz

Did I get my math right (I didn't do well in chemistry ) ?

Thanks!

Pure hypo. ..I don't know where you are located but I have a friend in friend in west new Haven that carries chemicals..I buy 25 lb pails and mix my own for paper with a little sodium bisulfite

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Peter Schrager said:

Pure hypo. ..I don't know where you are located but I have a friend in friend in west new Haven that carries chemicals..I buy 25 lb pails and mix my own for paper with a little sodium bisulfite

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Click to expand...

you are very lucky !

i called and called and called around rhode island
and no one carries it, so i am left to buying
it in a few lbs at a time containers from adorama
who has good prices on it, formula hypo
less than list price...

the Photographers Formulary sells in bulk.

I bought 25 lbs of hypo on eBay for about 65 with shipping, about 18 months ago. Seller is/was called prosupplyoutlet.

Tony,

Surf on over to jbhphoto.com/blog and click on the tiny header (right under the main banner) entitled "FORMULAS - Updated 07/14/2015". Scroll down the page a bit and you'll find a table showing the quantities needed for various final volumes of Plain Hypo.

Hope this helps.

My friend ships..city chemical
Easy breezy just measure out 1 lb in a plastic and mark it...then add 15gms sodium bisulfite...if anyone here calls tell him you know peter

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they also have one of the largest stocks of chemicals anywhere...not esoteric stuff like amidol...but great stuff like gold chloride and a few thousand other chemicals
I've mentioned this before but people like paying retail...
have a nice day!!
peter

Yes, the Chemistry Store sells it and their prices are reasonable and you can buy large quantities up to 50 lb containers. Go to Products/Chemicals A-Z. They also sell many other chemicals used in photography except developing agents. Besides inorganic chemicals they also sell TEA and various glycols.

http://www.chemistrystore.com/

aoresteen said:

1. Does anyone know if the Zone VI Hypo had sodium sulfite anhydrous mixed in or was it just sodium thiosulfate, ie 'pure hypo' ?

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There is no reason for us not to add Sulfite to such a fixer. It is no more expensive that Thiosulfate, added in small amounts and doesn't hurt fixer performance in these quantities.

aoresteen said:

2. My understanding is that sodium sulfite is added to extend the life of the fixer by absorbing oxygen. Without it, how long should the plain hypo fixer last in a tray? Should I add it in anyway?

Click to expand...

I have read statements that fixer without Sulfite lasts for a (short) dark room session but not more. With Sulfite it can last quite some time. Sulfite will scavenge Oxygen until it is used up. Oxygen will then go after the Thiosulfate, leading to a Sulfur precipitate, which in turn renders the fixer unusable.

Therefore, regardless what Zone VI Hypo did, do add the Sulfite. The recipe you suggested sounds quite reasonable. Don't worry about the exact composition of your fixer, you can safely multiply the numbers by four to convert from liter to gallon, i.e. 1000g Sodium Thiosulfate and 120g Sodium Sulfate to make 4 liters or one gallon or anything within that range.

The Zone VI "Plain Hypo Fixer" was, if I'm not mistaken, the same formula published by AA. Zone VI just packaged it for convenience sake (although mixing hypo and a bit of sodium sulfite isn't really a chore).

Adam's recipe follows:

Water at 90°-125°F - - - - - - - - - 750ml
Sodium thiosulfate pentahydrate - - 240g*
Sodium sulfite anhydrous - - - 30 to 60 grams (use more sulfite if storage is anticipated, 2 months maximum in any case.)
Water to make - - - - - - - - -1 liter
* Note: you can substitute 160g of the sod. thiosulfate anhydrous, but then be sure the water temp is not over 80°F!

Best,

Doremus

Thanks all! I will order the chemicals and make my own hypo. I will add the sodium sulfate to it.

mike c said:

the Photographers Formulary sells in bulk.

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I looked at their site. Their price for 20 pounds of sodium thiosulfate shipped to Georgia is $116. The Chemistry Store sells the same stuff for $53 shipped to Georgia.

aoresteen said:

Thanks all! I will order the chemicals and make my own hypo. I will add the sodium sulfate to it.

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Be sure to get sodium sulfite! Not sulfate...

Doremus Scudder said:

Be sure to get sodium sulfite! Not sulfate...

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Thanks! I checked my order and I did get sulfite

Alan9940 said:

Tony,

Surf on over to jbhphoto.com/blog and click on the tiny header (right under the main banner) entitled "FORMULAS - Updated 07/14/2015". Scroll down the page a bit and you'll find a table showing the quantities needed for various final volumes of Plain Hypo.

Hope this helps.

Click to expand...

It did, thanks. I re-did my conversion to 1 gal using JBDPHOTO's Hypo formula and here's what it is:


Water at 100-125° F 96 FL oz

sodium thiosulfate pentahydrate 32oz (908g)

Sodium sulfite anhydrous 4oz (114g)

water to make 128 FL oz (1 gallon)

Is the pool-supply grade of sodium thiosulphate adequate? It might be easier to acquire than some other variety of the chemical.

MartinP said:

Is the pool-supply grade of sodium thiosulphate adequate? It might be easier to acquire than some other variety of the chemical.

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Probably fine. It's not as critical as making developers. Maybe you can check with the distributor. If you can get a sample I'd check it for insoluble impurities.

I bought some bulk chemical years ago for a non-photographic purpose and was surprised to read on the bag something like 87% purity, and 7% insoluble. (this was aluminium sulphate for water purification) Some impurities sank, some floated! I'm glad I didn't have to put my negs in it!

Also, more recently, some cheap powdered pool chlorine (Chinese) from a major hardware chain left significant amount of scum.

john_s said:

Probably fine. It's not as critical as making developers. Maybe you can check with the distributor. If you can get a sample I'd check it for insoluble impurities. .....

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Sounds like you would have to filter it before using it.


UPDATE:

RE: my order with The Chemistry Store

Good news: The sodium sulfite arrived yesterday via UPS

Bad news: The sodium thiosulfate is on back order

The sodium thiosulfate arrived Monday. It's not packed in a bucket but in a heavy paper bag like a cement bag. I need to get a 5 gal bucket & top to keep it in.

I measured out the sodium thiosulphate tonight. I broke it down to 1 gal quantities and put it in 1 gal freezer bags, 908g (32oz). In total I got 25 bags as expected. 20 bags fit nicely in a Home Depot bucket (with top).

The sodium thiosulphate was not a powder. It's 'rice' size crystals. The bag was labeled as "PHOTO USE". Next up is to add the sodium sulfite and mix up the first gal.