Rollei liquid photo emulsion on glass - fixing problem

[Ron789]

Does anyone know why the emulsion comes off during fixing of a print on glass using Rollei Black Magic liquid emulsion?

We use the following workflow:
- thoroughly clean glass plate with baking soda and liquid detergent
- apply a layer of pure gelatin (ADOX colloids C)
- let this dry for a couple of days
- apply Rollei Black Magic liquid photo emulsion with a brush
- let dry for a couple of days
- expose the glass plate
- develop in Rollei RPN paper developer (1+9) with 3-4% RBM5 hardener
- rinse in clean water
- regular stop bath
- fix in Rollei RXN fixer, 1+7 solution

Everything goes fine UNTIL we put the glass print in the fix. But then, within seconds, the emulsion comes off in the fix and the image disappears.
The baths are all at a temp around 20C.
We also tried more diluted fix but the result was the same.
What should we do to ensure that the print survices the fixing bath?

 

[AgX]

"The emulsion comes off in the fix and the image disappears."

Do you mean the emulsion went off in a whole piece (as in finding the perfect means for emulsion lift-off)?
Or did the emulsion dissolve within the bath?

 

[Ron789]

"The emulsion comes off in the fix and the image disappears."

Do you mean the emulsion went off in a whole piece (as in finding the perfect means for emulsion lift-off)?
Or did the emulsion dissolve within the bath?

It dissolves or comes off in irregular flakes.

 

[mug]

from the manual

1. For coating metal, plastic, glass or ceramic tiles, a precoat with alkyd resin primer or oil-based polyurethane paint should be carried out, these special primers are available at art shops.
2. 
   Smooth and/or hard surfaces such as polished stone, glass or metal;
   we recommend also a precoat with LPE 510 in combination with LPE 410 - hardening additive solution (to improve adhesion and mechanical qualities).
   
   
   With smooth (polished or glossy) hard and non-absorbent objects, e.g. glass or ceramic tiles, to be coated it may be advisable to combine all 3 methods in order to avoid adhesion difficulties:
   1. adding ADDITIV HD LPE 510 directly to the developer ("A"), 2. harden indirectly ("B") and
   3. the direct hardening ("C").

 

[AgX]

But the OP did use a gelatin subbing layer and he did use a hardening developer.

Hoewever his subbing layer was not hardened. But he trusted in the developer doing its job there too.

 

[gone]

I think the things that mug discussed were not gelatin, but stuff that would stick to the slippery glass surface........ and then the emulsion would then stick to it. It makes sense, something like glass has no tooth to grab anything, it needs a primer applied first. Same w/ metals.

You might be able to use a piece of frosted glass. That might be toothy enough to hold onto the emulsion layer, but a primer sounds better.

 

[mug]

Here some info on this webpage. I used google translate to read the webpage

Emulsion photosensible sur du verre (Liquid LIGHT / Tetenal - Forum photo argentique

And Christhoper James book, chapter 27 page 771

Or give ADOX EMH-1a try

 

[Ron789]

Thanks for your feedback so far, guys!
The problem is not the adhesion to the glass. We used several coatings, varnish and gelatine, and both remained well stuck to the glass. The problem is that the light-sensitive emulsion comes loose from the varnish or gelatin coating.
We really don't understand this: we applied the same gelatin as a "primer" for paper and cloth (wool, linen) and the light sensitive emulsion remained attached to the "primer" well all through the process, with and even without hardener. But now that we use the same "primer" (gelatin or varnish) on glass, the "primer" survives the fix buth the light-sensitive emulsion dissolves or flakes off.
I looked at the info on ADOX EMH-1a; it looks like similar tor the Rollei RBM5 hardener we are using, as recommended by Rollei in combination with the RBM emulsion.
The fixer is also the same as we successfully used for paper and cloth prints with RBM.
We are completely puzzled.....

 

[Ron789]

from the manual

1. For coating metal, plastic, glass or ceramic tiles, a precoat with alkyd resin primer or oil-based polyurethane paint should be carried out, these special primers are available at art shops.
2. 
   Smooth and/or hard surfaces such as polished stone, glass or metal;
   we recommend also a precoat with LPE 510 in combination with LPE 410 - hardening additive solution (to improve adhesion and mechanical qualities).
   
   
   With smooth (polished or glossy) hard and non-absorbent objects, e.g. glass or ceramic tiles, to be coated it may be advisable to combine all 3 methods in order to avoid adhesion difficulties:
   1. adding ADDITIV HD LPE 510 directly to the developer ("A"), 2. harden indirectly ("B") and
   3. the direct hardening ("C").

Thanks, Mug.
Which instruction manual are you referring to? We use Rollei's RBM instruction manual (at: https://www.rolleianalog.com/wp-content/uploads/2020/09/RBM_Manual_EN_DE_R011901.pdf ) which does not mention LPE 510 or LPE 410, It recommends the Rollei RBM5 hardener, so that is what we use.

We do indeed use a primer (gelatin or varnish) and that adheres well to the glass. The problem is that the photo emulsion comes off the primer, while the primer is still there.

Any suggestion would be very welcome!
(BTW.... are you Mug because you're from Haarlem?)

 

[mug]

Here I found a manual of Rollei Black Magic and the use of this chemical on a smooth (glass) surface

https://www.maco-photo.de/files/images/Rollei_Black_Magic_gb.pdf

(BTW.... I'am a Mug from Groningen, I heard in Haarlem is Mug a nick name?)

 

[Ron789]

Thank you! The manual you found is an older version (dated 2010) but interestingly enough it contains some additional information on "emulsion take off", the problem that we seem to have. On page 5:
1. Mix our pure photo gelatine with distilled water (Barytage dissolution). Coat the glass board with it. Let the gelatine become touch dry. Does not have to hard-dry. Afterwards, you rinse the gelatine coating with hot water. Don’t use any cloth, sponges or the fingers! Only rinsing under hot water, nothing else. After drying the class is perfectly prepared and ready for the coating with Black Magic.

This information is not included in the current version of the instruction manual that we have used. Thanks a lot for finding this! We'll give it a try.

(BTW.... Yes, people from Haarlem are also called "Muggen")

 

[M Carter]

Never used the Rollei, but I've used tons of Foma and Liquid Light. Never done glass, paper and canvas only, but...

Cool chemical temps is always a good idea with liquid emulsions. They're really delicate, even on properly sized paper, they can scratch if you look at them too hard, and cool temps seems to help with this - go too warm and the emulsion will float right off. In the summer I've done things like coil my wash hose through a sink full of ice and chill my chems down a bit.

Just for laughs, get a can of polyurethane spray and give that a shot to sub your glass. Sometimes the simplest solutions work out well, especially if they mean not stocking up obscure chemicals! And heck, every house needs a can of poly spray (it's also good as a final protective coat on many emulsion projects).

 

[Lachlan Young]

I think it was Bostick & Sullivan (and others, possibly more in the conservation world) who used Aminosilane (or similar) to get gelatin to stay firmly stuck to glass. Treat with appropriate caution.

You might also want to have a look at the Kodak glass plate pre-coating preparations that were done - details are in Bob Shanebrook's book.