Acrylic ferrotyping: emulsion flecks off?

So I tried to ferrotype prints of this photograph: https://www.photrio.com/forum/media/by-the-old-mill.64884/

I bought a nice big plate of acrylic at the hardware store, and cleaned it with Windex. However, I'm seeing some slight texture in the emulsion, and I don't know if it's because of any residue on my plate, or a function of heat/drying time. Here's a closeup. The big white part is the reflection of the window, and the flecks I'm talking about are the pits just above.



I let the print dry in my garage which is around 20C, so it's pretty slow (took about 24h), humidity around 60%. Paper is Ilford FB Multigrade.

I would say that overall the result is nice because you get this super-shiny finish that I did not even believe was possible on FB, but I'm concerned about polishing off these slight defects.

I have seen similar effects with glass - though I think I attributed it to dust on the surface (it was purely a proof of concept I was doing & didn't clean the glass beforehand). Acrylic, if you don't clean it with anti-static cleaner, will quite happily suck dust out of the air quite spectacularly...

Dust. I gave up on ferrotyping pretty much because I could not get rid of it. I have a relatively high humidity dark room and no dust issues in any other part of the process. Seems very fine dust can cause this.

Thanks for the answers. I was also thinking about small particles in water.

I think I will do another try using a final rinse in distilled water with a drop of photo-flo, just for the heck of it.

Michel Hardy-Vallée said:

Thanks for the answers. I was also thinking about small particles in water.

I think I will do another try using a final rinse in distilled water with a drop of photo-flo, just for the heck of it.

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From recollection, Tetenal Mirasol wetting agent has instructions for using it for final rinsing before ferrotyping - I think it's used about 10x strength (eg 1+40 rather than 1+400) compared to use as wetting agent.

Lachlan Young said:

From recollection, Tetenal Mirasol wetting agent has instructions for using it for final rinsing before ferrotyping - I think it's used about 10x strength (eg 1+40 rather than 1+400) compared to use as wetting agent.

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Indeed, that's what I found with a quick Google. Some other thread on Photrio mentioned using regular strength Photo-Flo, so I'll try that first, and increase concentration if needed.

Michel Hardy-Vallée said:

Indeed, that's what I found with a quick Google. Some other thread on Photrio mentioned using regular strength Photo-Flo, so I'll try that first, and increase concentration if needed.

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Given that some of these surfactants are known to cause gelatin to swell (hence the use of some as development accelerators in emulsions/ processes), it does make sense for ferrotyping.