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ged
01-16-2014, 04:45 PM
Hi everyone,

I have some glass objects (not easily replaced) that were subbed with the Silverprint Hardening/Subbing solution, coated with Rollei Black Magic VC emulsion and then printed. The exposures for some were a bit off so I would like to remove the emulsion completely and start again.

Is there a simple and clean way to do this?

Thanks for any advice.


Regards,

Ged

cliveh
01-16-2014, 05:48 PM
soak in hot water.

Prof_Pixel
01-16-2014, 05:50 PM
You might try the hot water with some Clorox added

Bill Burk
01-16-2014, 07:02 PM
I've read that there is a problem re-using glass. Somehow it retains atoms of silver from a previously developed image - so it's not practical to re-use glass, because there will be ghost images from the previous photograph.

Maybe you can overcome this problem in this specific case ... if you can register the negative you are printing, so that it hits the same place as it did before.

It's in LP Clerc's Photography Theory and Practice section 388 Glass.... and he uses the words "It is almost impossible to re-coat glass from old photographic negatives"

Hexavalent
01-16-2014, 08:11 PM
Hot solution of sodium carbonate will turn the emulsion to mush. I re-use glass plates, and have never had problems with ghosted images, but I do use a subbing layer, so there is bit of a barrier between the glass and the silver. YMMV.

Bill Burk
01-16-2014, 09:39 PM
Hot solution of sodium carbonate will turn the emulsion to mush. I re-use glass plates, and have never had problems with ghosted images, but I do use a subbing layer, so there is bit of a barrier between the glass and the silver. YMMV.

That's great! Glad to know our historical problems are a thing of the past. I've got a hunch LP Clerc found it nearly impossible to re-use... used, commercially-prepared plates that were easy to obtain in those days.

Whiteymorange
01-17-2014, 06:25 AM
In days of yore my "uncle," a photographer for industrial firms and then the army, used to use citric acid to strip the emulsion from his plates. I only know this because as a very old man he knocked the bottle of acid over on the floor of his basement, and when his son asked him why he had that stuff around he said, "How else would I clean the emulsion off my plates before re-coating them?"

TheFlyingCamera
01-17-2014, 11:37 AM
After you get the emulsion off, you can mix up a solution of 1/3 rottenstone, 1/3 alcohol and 1/3 distilled water to use as a glass cleaner/polisher and clean the glass with it before re-coating. This is the stuff the wetplate-heads use to clean and prep the glass plates they use for ambrotypes before they coat. There's another "proper" name for rottenstone, but you can get it from fine woodworking supply places - they use it for polishing wood prior to staining.

ged
01-19-2014, 07:05 AM
Thanks for everyone's advice! I'll see which works well for me - it's great to have some options.

I assume I'll need to resub the glass before recoating. Does that sound right?

wildbillbugman
01-19-2014, 01:30 PM
Try straight Clorox, out of the jug. You should not need subbing. Look at my procedure for glass cleaning on www.thelightfarm.com.

ged
01-19-2014, 06:34 PM
Thanks for the Clorox tip.

I would have thought re-subbing is necessary as the cleaning would remove it as well? I've had problems with emulsion not sticking to the glass without a good subbing layer.