Liquid light emulsion: thicker application and / or multiple applications

[sjg2000]

Hi everyone. I'm wondering two things:

1. if it would be possible to apply the emulsion thickly to the paper, let it dry thickly, expose and process without everything just washing away/coming off the paper. I'm trying to experiment with relief (visible after dry down) if possible. I know you can achieve this with carbon printing, but is it possible with liquid emulsion? If I applied it thickly (say, I didn't heat it up as warm so it didn't melt as much, and applied it to paper in a thick concentrate) and exposed for a long time, after processing would I get a thicker deposit of metallic silver? Or would most of it just wash away?

2. If its possible to take a finished print and apply liquid emulsion onto it again, re expose, re process. Or would I need to size the area with clear gelatine first?

Both of these questions would pertain to small select areas, not an entire sheet of thick emulsion application.

Thank you!

 

[koraks]

Welcome aboard @sjg2000 ! (I think we've been in touch over email recently; it's nice to see you here!)

I'm trying to experiment with relief (visible after dry down) if possible. I know you can achieve this with carbon printing, but is it possible with liquid emulsion?

Not really. Keep in mind that a silver halide emulsion remains in place after application, other than a carbon transfer print, which is made by selectively washing away the gelatin. This does not happen with silver halide; all the gelatin remains in place. What is removed, is only the undeveloped silver halide itself, but this does not affect the thickness of the emulsion. So there's in principle no relief.

I say 'in principle' because there's one caveat: that of a tanning developer (at least in B&W). 'Pyro' developers (like PMK, Pyrocat, 510 Pyro, Moersch Tannol etc.) also harden the gelatin as a side-effect of development; i.e. the emulsion hardens where development of the silver image takes place. Hardened gelatin shrinks a little, and this results in a very minor relief. However, this is so minor that it's generally only visible on a very smooth substrate, like regular film or glass. On paper, it will be overpowered by the texture of the paper itself (even if it's a smooth, hot-pressed paper).

It's theoretically possible to coat a gelatin layer so thick and then develop it with a tanning developer that the relief shows. But I doubt it will work in practice.

However...the tanning has another side-effect: the gelatin is rendered insoluble. So you could take a non-hardened silver gelatin emulsion, develop the image with a tanning developer and then wash away the unhardened gelatin in a warm water bath. This is in fact exactly the approach that was/is used for making the matrices for dye transfer printing. Whether you will get relief that's visible on paper - I really doubt it to be honest. It takes a heck of a thick gelatin layer to get a visible relief when dry, on paper.

If you want to create a visible relief using gelatin, I would consider using an approach as done in e.g. oil printing, where a clear gelatin (pigment could be added to it) is hardened selectively through a negative (contact printed) using UV light. This can be done also with e.g. ferric ammonium citrate (which is also used for cyanotype).

If its possible to take a finished print and apply liquid emulsion onto it again, re expose, re process.

Yes, this should work fine!

 

[Chromium VI]

Hi everyone. I'm wondering two things:

1. if it would be possible to apply the emulsion thickly to the paper, let it dry thickly, expose and process without everything just washing away/coming off the paper. I'm trying to experiment with relief (visible after dry down) if possible. I know you can achieve this with carbon printing, but is it possible with liquid emulsion? If I applied it thickly (say, I didn't heat it up as warm so it didn't melt as much, and applied it to paper in a thick concentrate) and exposed for a long time, after processing would I get a thicker deposit of metallic silver? Or would most of it just wash away?

2. If its possible to take a finished print and apply liquid emulsion onto it again, re expose, re process. Or would I need to size the area with clear gelatine first?

Both of these questions would pertain to small select areas, not an entire sheet of thick emulsion application.

Thank you!

Avoid making very thick coatings, it will not increase density, and will make it almost impossible to remove the unexposed silver halides on the fixing step (learned it the hard way). If you want relief, you wanto go throgh a pigment process such as the ones suggested by koraks.

 

[sjg2000]

Great thank you both!

One more question: has anyone tried making a temp support for the liquid silver gelatine emulsion? Like what they do in carbon printing, i think Yuppo is used? or some kind of acetate? then the final support and the temp support are both wet, then sandwhiched together and i think left to dry. Then the yuppo/acetate peals away leaving the emulsion on the paper.
I was wondering if I could do a temp silver gelatine emulsion then transfer to arches platine (apparently designed for alt. photo work). This is because I want to avoid submerging the actual paper in any photo chem. Thank you, appreciate the help!

 

[koraks]

That's an interesting idea and it might work. Do not use Yupo for this - the gelatin will bond with it permanently. The support needs to fairly readily release the gelatin, so you could use materials that are used in the double transfer carbon process; mostly thin sheets of polythene or polypropylene - basically just thin, clear plastic. I use laserjet transparency sheets, which work well. You may have to apply a subbing layer of e.g. hardened albumen or hardened gelatin to the sheet for the emulsion to adhere sufficiently to it. Then do your silver halide process, and transfer it to a gelatin-sized support. I can't guarantee it will work, but in principle, it should.

For prepping the plastic sheets, first clean and de-grease them thoroughly; I use regular hand soap and a sponge and thoroughly scrub the surface I'll be using. Wash thoroughly to remove all soap. The subbing layer can be applied to the sheets by dipping the sheets in the solution and then hang to dry. I've used albumen diluted ca. 1+50 with water as well as gelatin at a dilution of approx. 0.5% (5g to 1000ml). The albumen can be hardened after the sheet is dry by misting it with ethanol/isopropyl-alcohol (IPA); it'll dry in a minute and is then ready to go. I mostly use gelatin, and add a little diazostilbene to the subbing solution, dip the sheets and hang to dry in a sunny place. The gelatin will be hardened once the sheets are dry. Instead of diazostilbene several other hardening agents may be used; chrome alum can work (needs no exposure to light), dichromate (nasty; does need UV exposure) and ferric ammonium citrate should do the job as well.

For the transfer of the image to a final support, size the final support paper with gelatin with a minimum gelatin load of 30g dry gelatin per square meter of paper. Apply as a 5-10% w/v solution, depending on what works well for your process. I generally just pour & spread it on soaked sheets, allow to set and then hang to dry. This gelatin sizing should not be hardened so it will exhibit maximum swelling (although mild hardening can still produce a workable situation). Arches Platine should work, but in this application there's no specific requirement on the paper regarding chemical makeup. I generally use more affordable printing papers. The main requirement is that the material is strong enough to withstand prolonged wet times and thick enough so that the gelatin sizing doesn't ooze right through it. 'Fine art' papers (for drawing, block printing, intaglio printing, watercolors etc.) starting around 250gsm and upward generally work well.

Mind you - I don't think this will necessarily solve the issue @Chromium VI points out; if you apply a thick photo emulsion layer, it will be very difficult to get it to fix out entirely. You'd have to experiment to see how far you can take it and to work out whether hardening the emulsion is beneficial, or the opposite (there's something to be said for either approach).

 

[Chromium VI]

The albumen can be hardened after the sheet is dry by misting it with ethanol/isopropyl-alcohol (IPA)

I didn't knew that, thanks!

this is because I want to avoid submerging the actual paper in any photo chem

A great problem in conservation of silver photographs is the processing chemistry (specially fixer) being retained on the emulsion and substrate (that's why RC paper needs less washing time, as it only needs to wash mostly the emulsion). Your idea will also prevent the retaining of chemicals on the paper base. The use of a transparent temporary support will also help knowing when the image is fixed. Some authors say that the image should be fixed for 3x times the time it takes to clear out the image. Less time might not remove all the silver halides, and more will only leave unwanted fixer on the emulsion.
To make a very thin coating of LL, you may want to make a Mayer rod (aka a coating rod, basically just rod or pipe with copper/stainless steel wire coiled around, it allows to make thin and even coatings).
For maximum permanence you may also tone the image with sulphide (sepia) or selenium, or if you don't want the color shift you may try to look for Agfa/Adox Sistan (it's a weting agent/silver stabilizer, it will regulate the propper amount of hypo left on the emulsion for maximum archive).

Keep us updated of your experiments.