Salt water final wash observation

[Photo Engineer]

Seawater acidic? I recall from the days when I kept a salt water aquarium, that I'd shoot for a slightly alkaline ph of around 8 or so. That, and lots of very expensive actinic lighting, would keep the fish and corals happy.

And if anyone thought photography was expensive, try a reef tank on for size.

That might well be due to the ammonia released by the fish, however the sea is a huge 'container' of carbon dioxide which would tend to buffer the water at about 6.8. The other salts such as Magnesium Chloride and Magnesium Bromde are acidic as are their Sulfate salts.

Therefore, my assumption that it is slightly acidic is chemically and physically justified but may be wrong.

In any event, the heavy salt content would tend to repress swell all by itself.

PE

 

[Paul Verizzo]

Vodka, orange juice, and Haist

That's what I settled for instead of swill. I mean wine. How sad that my Saturday nights have become chemistry texts.

The next time I process I'll dip a big bucket in the bayou in the back yard. That will no doubt save a lot of money.......once I strain out the mullet, pelican poop, and floating debris.

Oh yeah, specific comment back to PE, yes I too have photos 100 years old in perfect condition.....some of which as mentioned were processed on board ships. Others weren't and obviously got the super wash. My reason for starting this thread was that ALL 450 were in great shape. My father told me that after WWII when he was a pro he always used a HCA. Those pictures, too, are in perfect condition.

So tell me again why we selenium tone? (Boy, that ought to set off a war of words.)

Happy Daylight Savings Time to all....

 

[Paul Verizzo]

That struck me, too.

That's interesting that bicarbonate is as effective as it is, given how easy it is to come by.

Although only half the effectiveness of sodium sulfite, my gosh, it is so cheap and available, as you say. No mail order required, maybe soak a bit longer.

However, based on that chart I'm going for the Red Devil............

 

[David A. Goldfarb]

However, based on that chart I'm going for the Red Devil............

Well, since I've been experimenting with monobaths, my drains seem to be running better.

 

[janjohansson]

That might well be due to the ammonia released by the fish, however the sea is a huge 'container' of carbon dioxide which would tend to buffer the water at about 6.8. The other salts such as Magnesium Chloride and Magnesium Bromde are acidic as are their Sulfate salts.

Therefore, my assumption that it is slightly acidic is chemically and physically justified but may be wrong.

In any event, the heavy salt content would tend to repress swell all by itself.

PE

Seawater pH is generally 7.7-8.3. Acidic water or even too close to neutral would
make it impossible or very difficult for shellfish to live a decent life. =)

-j

 

[Photo Engineer]

Why selenium tone?

Well, that is interesting. It was developed not as a preservative, but as a toner, ergo the name. Someone got the idea that it was a preservative. It is, but when the paper is in worse shape than the image, selenium is not much good nor is any other preservative or toner.

I have pictures 50 years old that look good, but pictures from my collection from 100 years ago or thereabouts, show considerable wear and tear of the paper and deterioration of the image. Family photos from 150 years ago, not modern silver halide but tintype, look surprisingly good. One good picture was taken of a great grandmother on her way to the innaugural ball of President Grant.

Ctein used two of my phootos in his book on digital restoration. He has shown one of the good and most useful aspects of digital. My 87 year old uncle was able to see his father's face clearly for the first time as a young man thanks to Ctein.

PE

 

[Photo Engineer]

Seawater pH is generally 7.7-8.3. Acidic water or even too close to neutral would
make it impossible or very difficult for shellfish to live a decent life. =)

-j

Yes, I should have looked it up.

The formation of sodium carbonate and bicarbonate at the high salt content (ionic strength) offsets the effect of CO2. There are actually 3 scales for measuring pH of seawater, and all depend on ionic strength effects and require 3 sets of electrodes.

The pH values I found range from 7.2 to about 8.5 and vary by as much as 0.12 units. Electrode and location variations make it difficult to pin down more than that.

So, I would say that the entire mechanism is ion exchange, as the salts would offset the alkaline pH and swell would not be enhanced in a photo material while washing. Just a guess, as I have not tested it.

PE

 

[Chazzy]

It's amazing what a person can learn on APUG.

 

[Paul Howell]

In the 80's I lived in Southern Italy on the east cost, I washed my prints in the ocean, just tossed them in a net bag and let them wash for a couple of hours in a somewhat sheltered cove. The wave action kept the prints turning. Then a 1/2 hour soak in distilled water. 25 years later no issues at all.

 

[Paul Verizzo]

I love it!

In the 80's I lived in Southern Italy on the east cost, I washed my prints in the ocean, just tossed them in a net bag and let them wash for a couple of hours in a somewhat sheltered cove. The wave action kept the prints turning. Then a 1/2 hour soak in distilled water. 25 years later no issues at all.

And I'll bet they'll be good for another hundred years!

 

[Rafal Lukawiecki]

Do you use the Pole to carry the water with a pole and the buckets?

Erhm - clearing throat.

Rafal Lukawiecki

 

[Photo Engineer]

Erhm - clearing throat.

Rafal Lukawiecki

Rafal;

I understand, but my family came from 4 different parts of Europe (east and west), and a lot of them were Polish, Czech, and etc. So, no offence was meant. In fact, I cant see anything offensive in the post. My uncle, who was Polish, used to tell me Polish jokes. Half of my family needed an interpreter to be understood by the other half. So, again, no offence intended.



PE