Salt in Perceptol

[eSPhotos]

I am a big fan of Perceptol and want to mix my own.
Ordered S Sulfite and Metol but not sure of where I can get salt (NaCl).
Table salt contains iodine and the sea salt contains only 85% NaCl.
Where can I get pure salt OR can I use any of above cooking salt?

 

[Hexavalent]

"Kosher Salt" is usually plain NaCl - no iodide, no flow agents etc.,

 

[eSPhotos]

Thanks Ian.

I read some past threads on Perceptol and D-23 and salt was often mentioned in that thread.
Basically saying that salt with iodide should avoided.
What does iodide do to film developer or to film?
What about the other trace elements in the salt (all types) like magnesium, calcium and potasium?

 

[Jerevan]

Some time ago in another thread, Nicholas Lindan mentioned that even Kosher salt contains a anti-caking agent. Depending on where you live, you may use something called pickling or canning salt. In the US you may find pure NaCl at for example http://www.bostick-sullivan.com/.

 

[Ian Grant]

Actually the Iodised salt would have no ill effect with Tmax and Delta films as they have a high Iodide content anyway and it's already in the emulsion as Silver Iodide and this leaches into the developer during processing. I've used D23 with Sodium Chloride added, and tested both Iodised table salt and lab grade Sodium Chloride with no effective differences however that won't be the case with all films.

The presence of Iodide can enhance adjacency effect and it does build up in replenished developers along with bromide which is why bleed replenishment is used with Metol/Hydroquinone developers, PQ developers are more tolerant of Iodide levels so can be replenished by topping up.

In practice Iodide was added to High Acutance developer fomulae but in more recent years it's been found to have no effect, purely because the level in the films is no so much higher greater.

Ian

 

[eSPhotos]

Thanks guys,
Just in case, I bought a couple types of salt to try out on not-so-important films.
Washed sea salt with no additives and rock salt with no additives.

 

[Ian Grant]

Neither are likely to be pure enough, to many other trace elements.

Ian

 

[Gerald C Koch]

The problem with using table salt is not only that it contains iodide but that it usually contains an anti-caking ingredient that is insoluble in water. This makes solutions of it cloudy with the chance of leaving a residue on the film. It is possible to buy table salt without added iodide.

Kosher salt also contains an anticaking ingredient. This tends to be different for various brands. Some brands contain sodium ferrocyanide. Before buying read the label.

Pickling salt is probably the best choice. It is available at least seasonally in the US. It contains either no additives or none that would be photographically active. When making pickles you don't want a cloudy brine or anything which might change the color or taste of the pickle.