Ascorbic Acid to dissolve silver off film..

[Athiril]

Is an NaOH / Ascorbic acid solution what is normally used to remove exposed silver from a negative in order to make a positive (i.e. the exposed negative is clearedof all silver, the remaining unexposed halides exposed to light and redeveloped to form a positive?)

I was considering shooting paper negatives and processing them directly into positives, but couldn't find the process.

Its a developer solution, just not in this strength normally.

I assume you could just copy the b&w reversal process paper, but with whatever you develop paper with normally to your taste and a weaker version of the bleach.

I would recommend not using dichromate bleaches, as dichromate according to it's MSDS is a confirmed carcinogen for humans as well as mutagenic, while permanganate is listed as being only mutagenic on bacteria and yeast only.

This all sounds like a way to make a big mess...

Is the point of this to recover silver metal or just to have some fun? Or perhaps both?

It's rather an interesting looking mess, especially the settled copper sulphate-precipitate solution

[Photo Engineer]

Oh, Sandy, what thoughts you are projecting here.

Now we know your darker side.

Anyhow, to my knowledge only HydroFluoric Acid will totally reduce a human (or any) body to nothing but liquid and gas. You have to do it in a special container though or it eats the container. I believe that a ceramic bathtub was the container of choice. Sodium Hydroxide comes next. And, the nice thing about NaOH is that it, like HF, dissolves most clothing as well.

You can rest easy now, knowing this.

PE

[hrst]

But Mr. PE, how do you know all this??

Scary!

[Kirk Keyes]

It's rather an interesting looking mess, especially the settled copper sulphate-precipitate solution

That looks like some of the "science" experiments I used to make as a teenager. Thanks for sharing the photos!

[Kirk Keyes]

Anyhow, to my knowledge only HydroFluoric Acid will totally reduce a human (or any) body to nothing but liquid and gas.

I think you will find there will be a lot of calcium solids from the bones left after hydrofluoric acid gets done.

There was a Dateline NBC murder story the other day where some lady that owned a lab had disposed of someone in a barrel of aqua regia (nitric + hydrochloric acids), but there were still some chunks left that they got DNA out of. The person had only been in there for a month.

A lot of sulfuric would probably digest someone, but there would again be some solids (calcium sulfate). The sulfuric would dehydrate it, then char it, and all the organics would eventually turn in to a black, oily goo.

[Photo Engineer]

Ahh, I would just flush the CaF2 slurry down the drain. That is what it would be.

PE