question for fixer experts

removed account4 · Dec 2, 2009

hi

every once in a while people ask about
home brew fixers or things that can be used
to fix film and paper without using something
bought specific from a chemical supplier that caters to photographers
or a photography branded product.

often times pool suppliers are mentioned because the chemical used
to reduce or neutralize chlorine is the same as hypo.

i know plain hypo is sodium thiosulfate
the stuff pool suppliers sell is sodium sulfite ...

what exactly is the difference between the two ?

thanks in advance!

john

Ian Grant · Dec 2, 2009

Sodium Sulphate Na2SO4 is entirely different to Sodium Thiosulphate Na2S2O3 and is used as a hardening agent in tropical developers. It's not a silver solvent so no use as a fixer.

Ian

CBG · Dec 2, 2009

Sodium thiosulfate is used in pool chemistry.

Fix = Hypo = sodium thiosulphate - used in swimming pools and aquariums to reduce chlorine levels.

Photo Engineer · Dec 2, 2009

Sodium Sulfite is also used in pool chemistry. Both Sulfite and Thiosulfate will scavenge Chlorine.

Are you sure that you didn't get the name Sulfate mixed up with Sulfite?

PE

removed account4 · Dec 2, 2009

thanks for your help ...!

yes ron, i was a bit mixed up ...

john

juan · Dec 2, 2009

I've found listings for Sodium Thiosulfate at online pool supply places. Other folks have said they have found it at local pool supply places, but it seems these people are all in the northeast or midwest. I have checked with every pool supply place within 100-miles of my home in Florida, and none of them have Sodium Thiosulfate, just sodium sulfite. I wonder if the chemical is used regionally.
juan

RalphLambrecht · Dec 2, 2009

CBG said:
Sodium thiosulfate is used in pool chemistry.

Fix = Hypo = sodium thiosulphate - used in swimming pools and aquariums to reduce chlorine levels.

Just as a side note, ever wondered why the word 'hypo' is not a part of sodium thiosulfate?

Commercial fixers are based on sodium or ammonium thiosulfate and are often called ‘hypo’, which is short for hyposulfite of soda, an early but incorrect name for sodium thiosulfate. Unfortunately, some practitioners have continued using the erroneous term and expanded it referring to any type of fixer as ‘hypo’ now.

removed account4 · Dec 2, 2009

juan said:
I've found listings for Sodium Thiosulfate at online pool supply places. Other folks have said they have found it at local pool supply places, but it seems these people are all in the northeast or midwest. I have checked with every pool supply place within 100-miles of my home in Florida, and none of them have Sodium Thiosulfate, just sodium sulfite. I wonder if the chemical is used regionally.
juan

hi juan

when i was in france the summer of 08'
i checked spa and pool supply places there
and they they had sodium sulfite
and most all of the pool suppliers around me here in rhode island
have sodium sulfite as well. today, i managed to find someone who carried
sodium thiosulfate, but in the end it will costs the same ( or more! ) to buy it from them
as it would if i just bought it from the formulary or b&s ...

i usually use rapid fixer ( sprint ) the factory is a few miles from my house
and i can get it online or from my local photo retailer ...
i was hoping to try my hand at salt printing soon, since you can't use
rapid fixers with that, and i was planning to buy plain thiosulfate cheaply without
having to deal with shipping from montana or the land of enchantment,
... at least now i know the difference between sodium sulfite and sodium thiosulfate,
and how it won't save me any money buying local ...

thanks again!

Photo Engineer · Dec 2, 2009

juan said:
I've found listings for Sodium Thiosulfate at online pool supply places. Other folks have said they have found it at local pool supply places, but it seems these people are all in the northeast or midwest. I have checked with every pool supply place within 100-miles of my home in Florida, and none of them have Sodium Thiosulfate, just sodium sulfite. I wonder if the chemical is used regionally.
juan

Hypo, or Sodium Thiosulfate is generally not used in hot humid climates. This is due to its hygroscopic nature, or the tendancy to absorb moisture from the air, and its tendancy to decompose with heat. Therefore, special tropical packing is needed for Hypo in Fla and generally across southern US.

The Military has specs for "tropical Hypo, packing thereof" which is to be adhered to to prevent problems.

So, yes, there is probably a regional preference for the pool conditioners as well.

PE

totalamateur · Dec 2, 2009

A quick googling shows one source
http://www.horizonpoolsupply.com/website/store/index.php?strWebAction=item_detail&intItemID=1094
at a little over a buck a pound. Don't know that I'll use 50Lbs of fixer in this lifetime..

Compared to the formulary's price of $3/lbs or so.

Then again - would you rather your fixer come in a brown paper sack or a reagent bottled marked 99.9% USP?

Not much other useful chemicals on the pool site, though I have heard of people using heated bromine pool tablets to produce bromine gas - might be useful for something...

removed account4 · Dec 2, 2009

totalamateur said:
A quick googling shows one source
http://www.horizonpoolsupply.com/website/store/index.php?strWebAction=item_detail&intItemID=1094
at a little over a buck a pound. Don't know that I'll use 50Lbs of fixer in this lifetime..

Compared to the formulary's price of $3/lbs or so.

Then again - would you rather your fixer come in a brown paper sack or a reagent bottled marked 99.9% USP?

Not much other useful chemicals on the pool site, though I have heard of people using heated bromine pool tablets to produce bromine gas - might be useful for something...

hi totalamateur ..

thanks for the link!

i wish i had room for 50lbs of sodium thiosulfate!
if i did, it would cost 58$ for the chemical and 35$ to ship it to me ..
since i couldn't find any sizes less than 50lbs on their website, i called and found out that
... a 10lb bucket costs about the same as the formulary
... and a 25lb bucket costs about as much as their 50lb bag ...

- john

BetterSense · Dec 2, 2009

I wanted to lay in a good supply of sodium sulfite but couldn't find any locally at all. I checked all the pool stores I could find around north Dallas and none of them had Sodium Sulfite....or else none of them wanted to sell me any. I ended up having to buy a 13-pound bucket from thechemistrystore.com.

totalamateur · Dec 2, 2009

The local photo shop sells Kodak branded fixer for $3 for a liter package. Since I only go through one a month or so, it doesn't hurt my feelings. Since I use my Hypo to sensitize film emulsions, I'd prefer it to be a reliable grade since emulsions seem to be picky about impure addenda

I think the hardener in the Kodak fixer is giving me issues with my thicker than normal plate emulsions. The next batch I'm going to mix up straight 5-10% hypo and fix with that to see if I get any better results, with a separate sodium metabisulfate hardener.

Silver Nitrate on the other hand is just outrageous. Wish I could get that for $3 a pound. It's almost enough to make me want to take a trip to mexico to buy silver and red fuming nitric acid.

I'm rambling so I guess I'll hit the submit button.

removed account4 · Dec 2, 2009

its funny

buying sodium thiosulfate from a pool supplier has the same stink
as buying things from e-Boo. because we are buying from them
we think we are getting a sweet deal, but in reality it is probably cheaper
and much less of a hassle to buy from a photo store ...

juan · Dec 2, 2009

I buy mine from The Chemistry Store. Be warned that they add a fee at the very end of checkout. I usually get together with several local photographers so that shipping is spread among several people.

Thanks, PE. That's interesting, but I've used plain sodium thiosulfate for years, leaving it out in the heat, and never knew I might have problems doing it.
juan

neelin · Dec 2, 2009

OTOH if you want Ammonium Thiosulfate, rapid fixer, you could get this from your Agricultural/Turf chemical dealer (think golf if you live in the city).

Ammonium Thiosulfate
www.plantfoodco.com Ammonium Thiosulfate 12-0-0
I've been using it for about a year. 2.5USG was about US$48 at the time I bought it.
robert

dancqu · Dec 2, 2009

The Difference -- One Atom

jnanian said:
i know plain hypo is sodium thiosulfate
the stuff pool suppliers sell is sodium sulfite ...
what exactly is the difference between the two ?
thanks in advance! john

Sodium sulfite; Na2SO3 - Sodium thiosulfate; Na2S2O3
The later is a THIO sulfate. One of the two sulfur atoms
is standing in for one oxygen atom. Thio, sulfur.

Sulfur will dissolve in sodium sulfite yielding
sodium thiosulfate.

BTW, you did say sulfite. Dan

question for fixer experts

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