Monday, December 20, 2010

experiments

Today after meetings I tried to produce a receiver sheet by adding lead acetate to Kodak glossy premium photo inkjet paper.  Not only did the negative stick to the surface and rip off the entire top layer after spreading the reagent, but nothing at all seemed to be produced on the negative.  I had hoped for at least a faint image on the negative, but a silvery mess instead.

Loading, exposing and unloading sheet film holders reminded me why this project might be worth the effort, as it is a pain and a bother. Wish I had some Efke 25 readyloads ready.

8 comments:

James M said...

Lead acetate is pretty damn toxic. be careful with that stuff!!

Bob Crowley said...

I will be! It was used as a sweetener for beverages up until the 1600s. Lead acetate is the active ingredient in Grecian Formula hair darkener, which is why I used it - bought at the drugstore. An FDA/NIH study I read before using this material showed no increase in lead internally with proper use. meaning not used on abraded scalp. I figure if I can put it on my head then it should be OK on a receiver sheet that will be covered with zinc acetate (coater) later.

Did you know that for years Polaroid used pure lead for their pods? Yes, even into the 60s, lead was the material of choice. Lead can be a hazard, but, lead flashing is still widely used all over the world. It is impervious in some instances and safe when used properly.

Zinc acetate, its cousin, is formed by mixing the acetic acid which photographers are also careful with. In small amounts in vinegar, acetic acid is good but too much can be fatal. Anyway. the nice thing is that the metal acetates are stable and bond very tightly with silver.

Anonymous said...

Very interesting uses, I was actually thinking of Pb(OAc)4, not Pb(OAc)2, which I am most familiar with as an oxidant in organic chem, and is inherently more toxic.

I am curious, did you obtain it simply by concentrating the hair dye solution, or by some precipitation protocol?

Bob Crowley said...

I just used the native solution as sold. There are surfactants and fragrances in there that could be trouble but this is good enough for a first approximation. The key problem of the day is not as much the DTR rate but the surface wetting and adhesion of the negative that gets sucked onto the paper with absorption of the hydric acid.

jb said...

You are indeed the MacGyver of the photographic world. Love it!

Anonymous said...

True... but... hydric acid? Was that a typo or are you just messing with us?

Bob Crowley said...

You caught that! Not a typo, but a common joke, yes. I think we all have a good sense of humor in this project. For more about hydric acid go to http://www.dhmo.org/

There is even an MSDS for the stuff

James said...

;-)

PS Nice results on your next post! should be exciting!