Non-hardening vs hardening fixer

[sam_groo]

What is the difference?<br> Why does it depend on what type of developer your using?<br><br>

Thanks

[ronald_moravec1]

I used to be required for old films to harden the emulsion. All films are prehardened today

excepts for perhaps EFke. I never used hardener on them either. They protect only wet

film.

 

Paper will not not tone properly if hardened and does not dry flat.

 

I have discarded dozens of bottles of hardener furnished with Rapid Fix . My current TF4

has no hardener in it so i need not throw it away.

[brucecahn]

I agree with Ronald. Hardener is not normally needed. The exception is sheet film being washed in a big tray with other sheets. Hardener keeps it from getting scratched.

[larrydressler]

Since I use a lot of EFKE I keep a Gallon of Fixer with hardener on hand for that and Foma film but all other film gets Non Hardening Fixer.

[ckp]

I agree with everybody on a non hardening fixer for films but I like to use a hardener for paper. preferably an A B so I can hold out hardening till after toning on fb papers (staining). It really does make a more durable print even after drying and flattening. Although I have a passionate dislike for spotting hardened prints.

[tomweis]

I believe hardener makes prints less archival.

[profhlynnjones]

You almost never need hardened hypo. among other thngs if you need any kind of after treatment it becomes very difficult and is hard to be evenly absorbed.

 

Lynn

[caesar_augustus]

Ekfe and other sensitive emulsion films do call for hardener in their film tech/data sheets.

 

This is the way I view it: Hardener is used absolutely last, in the last fixer treatment, after you tone for the final time.

 

For film: selenium toner makes film denser. This is because it is applying a layer of selenium metal over the layer of already exposed silver halide metal.

 

What you do is this: use a non-hardening fixer > Rinse > HypoClear > Rinse > Selenium Toner > Rinse > Hardening Fixer > Rinse > HypoClear > Rinse.

 

The last Fixing step, "hardens," the selenium and silver together.

If you use a Hardening Fixer before Selenium Toning, it has a hard time toning at all.

 

Now you may get an argument that this totally goes against the idea of reducing wet times but that is another ball of wax.

 

With Paper it is the same process. Selenium Toner and fixer don't like to come in contact with eachother that is why it is important to hypoclear between the two chemicals.

[frank.schifano]

By the time the sensitized material is introduced to the toner, there should be no more silver salts (halides) left in the gelatin. If there are, stains will occur. The purpose of a fixer is to convert these silver salts into a water soluble form and wash them out of the emulsion. There is no need for re-fixing after selenium toning, since there should be no un-reduced silver halides remaining. The toner affects only the reduced silver in the print or negative, converting some or all of it to silver selenide. The amount of converted silver is dependent upon the strength of the toning solution and the time the film or paper is in contact with it.

 

These days, hardeners are typically potassium aluminum sulfate. This stuff simply toughens up and slightly shrinks the emulsion, kind of like the way a skin forms on the top of a bowl of Jello after a couple of days in the refrigerator. The hardener has no effect at all on the silver in the emulsion. Hardeners make it more difficult for aqueous solutions to diffuse through the toughened layer, and that's why wahing and toning become less efficient. In the past fomaldehyde was used, but is no longer because of its toxicity.