hydrochloric acid

[sanking]

I sometimes use hydrochloric acid as a clearer of last resort in both kallitype and palladium printing. Just ran out of a large bottle I had on hand since about 1995. Have heard that muriatic acid, which one can sometimes buy at home supply stores, is same as hydrochloric acid.

Can anyone verify that muriatic acid is indeed same as hydrochloric acid?

Sandy

 

[magic823]

Muriatic acid

hydrogen chloride
Related: Chemical Compounds

chemical compound, HCl, a colorless, poisonous gas with an unpleasant, acrid odor. It is very soluble in water and readily soluble in alcohol and ether. It fumes in moist air. It is not flammable, and the liquid is a poor conductor of electricity. Hydrogen chloride is prepared commercially by the reaction of sulfuric acid with sodium chloride (common salt); niter cake, a mixture of sodium bisulfite and sulfuric acid that is a byproduct of nitric acid manufacture, is sometimes used in place of sulfuric acid. Hydrogen chloride is also produced as a byproduct of the manufacture of chlorinated organic chemicals. It can be prepared directly by reaction of hydrogen and chlorine gases; the reaction is very exothermic and takes place readily in sunlight or at elevated temperatures. Although anhydrous (water-free) hydrogen chloride is commercially available as a high-pressure compressed gas in steel cylinders, most of the gas produced is dissolved in water to form hydrochloric acid (see acids and bases ), a commercially important chemical. Pure grades of hydrochloric acid are colorless, but technical grades, commonly called muriatic acid, are often yellow-colored because of impurities such as dissolved metals. Most hydrochloric acid produced has a concentration of 30% to 35% hydrogen chloride by weight. The major use of hydrochloric acid is in the manufacture of other chemicals. It is also used in large amounts in pickling (cleaning) metal surfaces, e.g., iron before galvanizing. It reacts with most common metals, releasing hydrogen and forming the metal chloride; with most metal oxides and hydroxides it reacts to form water and the metal chloride. Hydrochloric acid is also used in small amounts in processing glucose and other foods and for various other uses. Concentrated solutions are strong acids and highly corrosive. Hydrochloric acid is not an oxidizing agent but can be oxidized by very strong oxidizing agents, liberating chlorine gas. In dilute solutions of the acid the hydrogen chloride is almost completely dissociated into hydrogen and chloride ions . A solution containing 20.24% hydrogen chloride by weight is azeotropic, boiling at a constant temperature of 110°C at atmospheric pressure. Hydrogen chloride also forms monohydrates, dihydrates, and trihydrates that are liquids at room temperature.

 

[Jorge]

Muriatic acid is just a lower grade of hydrochloric acid sometimes used by stone masons etc. It might have some impurities that could stain your print. It is what I use to pre-treat socorro and the few times I have used it for clearing I have seen at times a "developing" on the edges of the coating It looks like a very thin dark line that is impossible to erase.

Sometimes with double coating it is the only thing that clears the print, so I use it but it is a crap shoot. It is very hard for me to get high grade hydrochloric acid, but if it is easier for you I would recommend you stay away from muriatic acid to clear prints. I have ruined a few this way.

 

[donbga]

I sometimes use hydrochloric acid as a clearer of last resort in both kallitype and palladium printing. Just ran out of a large bottle I had on hand since about 1995. Have heard that muriatic acid, which one can sometimes buy at home supply stores, is same as hydrochloric acid.

Can anyone verify that muriatic acid is indeed same as hydrochloric acid?

Sandy

Muratic Acid is a 37% solution of hydrocloric acid. You can purchase 2 gallons at Home Depot for about $8.

Don Bryant

 

[dr bob]

Once upon a time, there was a company that used Hydrochloric acid in carboy quantities. Their supplier originally did not have the means to purify their product and it had a greenish cast (muratic acid). Then the supplier improved his method and shipped out a water-white product. The consumer complained that it didn’t look as potent as their old product – so the supplier retrieved all the carboys, dropped a penny nail in each and shipped them back. “That’s more like it.”, said the consumer.

 

[sanking]

Muriatic acid is just a lower grade of hydrochloric acid sometimes used by stone masons etc. It might have some impurities that could stain your print. It is what I use to pre-treat socorro and the few times I have used it for clearing I have seen at times a "developing" on the edges of the coating It looks like a very thin dark line that is impossible to erase.

Sometimes with double coating it is the only thing that clears the print, so I use it but it is a crap shoot. It is very hard for me to get high grade hydrochloric acid, but if it is easier for you I would recommend you stay away from muriatic acid to clear prints. I have ruined a few this way.

Well, I tried the muriatic acid and it worked fine for me.

I bought a gallon of the 30% solution at Lowes for less than $4.00. It is very clear and did not cause any kind of unwanted staining on my prints, either in kallitype or palladium.

Hydrochloric acid is the most effective clearer I have found for clearing double coated prints. It even did a nice job of clearing some old prints with stain that had been processed several weeks ago. I am using it in solutions ranging from 1/2% to 2%.

BTW, I think the fact that a hydrochloric acid solution as strong as 4% will not cause any bleaching or regression of a palladium toned kallitype is a good indicator of how effective the toning process is in replacing the silver with palladium. If you were to attempt to clear an untoned kallitype print even a very weak solution of hydrochloric acid would cause severe bleaching of the image

Sandy

 

[BBMOR]

muriatic acid is in Belgium the same as hydrochloric acid ,muriatic acid is the trivial name ,the color yellow to green is due to Fe contamination ,the specs of the products are different but both are strong acids and needs to be handeld with care

jm

 

[Photo Engineer]

Sandy, I would take that acid back. You didn't get the penny nail dissolved in it!

PE

 

[Jorge]

Hydrochloric acid is the most effective clearer I have found for clearing double coated prints. It even did a nice job of clearing some old prints with stain that had been processed several weeks ago. I am using it in solutions ranging from 1/2% to 2%.



Sandy

I am in the same boat, HCL is the only thing that will work for me when I double coat. Anyhow, sometimes it is better to be lucky than smart...

 

[nworth]

Muriatic acid (about 6M HCl) usually works for photo compounding. If you only need low concentrations and small amounts, an easier and safer way is to combine sodium bisulfate (_not_ bisulfite, but sodium hydrogen sulfate) and sodiun chloride (salt). Very roughly, 2g of bisulfate and 1g of salt should give the equivalent of 2cc of muriatic acid.

 

[psvensson]

Has anyone used muriatic acid in a cyanotype clearing bath? I don't think some iron impurities would mess up that process. I usually use citric acid, but it's actually not that easy to find.