Trying Zerochrome-SbQ (PVA-SbQ)

PGum said:

In gum printing, a hake brush is indispensable for spreading out those hills and valleys left by your brush. Using it dry and with a light touch, and starting perpendicular to those marks, then going parallel, and sometimes a little back and forth with perpendicular/parallel directions. It may be worth investigating this technique.

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I believe Calvin has said that this technique doesn't work with PMF which makes me think it won't work with PVA-SbQ either, maybe it gets stickier faster than gum as it dries? That said, Calvin has said something about using a badger hair brush to even out PMF coats recently, so maybe he's figured out a way.

It certainly would thicken up faster and likely reaches a point of gelation which is unbrushable, unlike gum. If I get time next week, I will make an attempt.

@AndrewBurns Here a small clip of how I develop the print
- in a water bath of around 35°C
- 2-3 min upside down in the bath
- I turn it and start shaking it. I noticed that ticking on the side of the bath helps to loosen the non-fixed emulsion.
- It takes me around 5 minutes to develop a print.

@PGum thank you for your info. I'll give it a try

BePan said:

Here a small clip of how I develop the print

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For people who want to view this, this is how it worked for me on Win11:
Download zip file
Unpack the .mp4 file to a folder on machine
Play with VLC Media Player (Windows' builtin player refused to play this).

AndrewBurns said:

The PVA is pretty well adhered to the glass. You can still rub it off with your thumb but I'm not sure how easily it would transfer onto another substrate. I'm pretty happy with being able to transfer onto glass at this point anyway as I have some images in mind that the process would suit.

Actually I think this technique would work best for carbon rather than PVA, I imagine that having the gelatin harden from the substrate upwards would significantly reduce the issue of highlights flaking away by giving them a ton of mechanical support (in the form of the glass). Again, impossible to transfer because the gelatin is hardened onto the glass surface, but fine for some things like orotone.

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Congratulate! This is also our experience: back exposure on glass to prevent thin surface layer curing under low exposure doses, which is then washed away during development. I suspect this is also the principle behind the excellent results in Bepan's experiment: the top layer contains a large amount of pigment, so even if UV attenuates as it passes through, the bottom layer, which contains a small amount of pigment, will cure first.

Additionally, you mentioned earlier that pigments can effectively prevent halo and diffusion. Our experience to this, besides colorful pigments, UV absorbers without color (TINUVIN® 234, or water-soluble TINUVIN® 1130) can also be used to adjust different materials without change their color.