THE IMAGE LITERALLY DISSOLVES...

[Dan Salzmann]

I want to take a 6x7 transparency and then somehow keep it flat and put it in a glass dish that would be softly underlit for the transparency. Then I want to add some transparent acid that would dissolve the image and film the acid eating into the image.

 

What acid should I use?

[Filip Plesha]

.....Ok, thanks for the help, it worked...now what chemical do I use to get the image back :D

Edited February 13, 2005 by Filip Plesha

[John Pytlak RIP]

I want to take a 6x7 transparency and then somehow keep it flat and put it in a glass dish that would be softly underlit for the transparency. Then I want to add some transparent acid that would dissolve the image and film the acid eating into the image.

 

What acid should I use?

<{POST_SNAPBACK}>

 

You could try sodium hypochlorite laundry bleach (e.g., "Clorox"). It will quicky fade any dye image, and eventually dissolve the gelatin emulsion.

[Dan Salzmann]

Thanks John. In fact I would like to see the base get eaten away as well. Any suggestions?

[John Pytlak RIP]

Triacetate base is dissolved by acetone (VERY flammable!). You could try dissolving the base completely in acetone (it will take several hours), before your shoot, leaving only the thin gelatin emulsion. Carefully put the image-carrying gelatin emulsion into your dish (it will look like very thin film), then fade the dyes and dissolve the gelatin with the sodium hypochlorite bleach solution. I've never done it, but it should work.

 

Note that polyester (ESTAR) base used for current motion-picture prints does NOT dissolve in any common solvent or chemical.

[Dan Salzmann]

Does that mean that the acetone will "seperate" the emulsion from the base while leaving it intact? Do all Ektachrome emulsions have a triacetate base?

[John Sprung]

You might also experiment with a heat gun, the kind electronics techs use for shrink tubing. If you melt the base without burning it, you might get an effect you'll like.

 

 

 

-- J.S.

[John Pytlak RIP]

Acetone will slowly dissolve triacetate film base, leaving only the gelatin emulsion behind. Very high temperatures (as from a heat gun) will likely char or blister the film before it melts the support.

 

Most of the Kodak EKTACHROME color reversal films are on triacetate base, but some may be on polyester (ESTAR) base (e.g., 2239, SO-251, 2253)

[Dan Salzmann]

I find it astonishing that there is not a transparent acid that will "eat" film.

Is there any way of knowing which ektachrome emulsions have a triacetate base and which don't?

Clorox has a very distinct green tint that will be problematic. Any other substitutes?

[Guest Ian Marks]

Could I suggest that you do this digitally? There are countless *non-destructive* ways to achieve this kind of effect in a program like Combustion or After Effects, and they can be tweaked until the cows come home. If you're shooting with a locked-off camera, you'd shoot the backplate without the transparency element and again with it. Have those two shots scanned to digital files and hand them off to a skilled artist to create your effect.

[John Pytlak RIP]

I find it astonishing that there is not a transparent acid that will "eat" film.

Is there any way of knowing which ektachrome emulsions have a triacetate base and which don't?

Clorox has a very distinct green tint that will be problematic.  Any other substitutes?

<{POST_SNAPBACK}>

 

Triacetate base can usually be torn, ESTAR base is much more tear resistant. ESTAR is also birefringent between crossed polarizers. Hypochlorite bleach is easiest to obtain. You can probably color time the slight yellow-green tint of the liquid bleach to appear colorless.

 

Don't forget that film is designed to go through very alkaline developers and very low pH stop baths. It's hard to hurt the image, but a strong oxidizer like chlorine bleach will do it.