I tried to develop a correction curve applicable to a digital negative for home-made POP, and (without being too scientific) came to use the familiar inverted s-shape again, used quite mildly though. When printing image files on transparency with an Epson Pro 3800 I realized that I’d need very high ink densities, such that Epson’s own printer driver cannot produce. A solution to the problem could be QuadTone RIP, which can separately adjust each ink’s output density. I think we should definitely check that when we get some time…
I tried a dark green hue for the UV blocking color, but even if I increased the ink density in the printer driver the output could not block enough UV light. So I thought I’d try a double negative – two identically printed transparencies registered and sandwiched together. I have noticed this being a familiar method to some serigraphy printmakers, e.g., to increase the film density. I used to think it would be hard to use in photographic images, with delicate tones and fine details, where every little bit of misalignment would show… but it was quite easy actually, and the dimensions of the two transparencies (Agfa CopyJet) really were exactly the same, so it wasn’t too hard to register and tape them together accurately.
This Photoshop correction curve was applied to the grayscale positive image, which was then inverted to negative. The image was then filled with 12R-24G-0B.
Adding silver nitrate to b&w photographic paper emulsion helps to increase its sensitivity, and the tone range will resemble more real POP. Below are some tests with different papers – the left picture shows the image after exposure, on the right the same image after the wet processing. Before the exposure all the samples were treated with silver nitrate (saltprint sensitizer: 12 % silver nitrate solution) diluted 1+2 with water.
Toning was done with two simple formulas: gold and palladium toner (see formulas below), and also Tetenal Gold Toner was used.
As we can see, the results greatly depend on the emulsion and its treatments. To get certain previsualized end results won’t be necessarily easy – accident will also play its role. On the other hand, that’s the fun of alt-printing; to achieve a wanted result will ask understanding and predicting the processes, and sometimes one has to accept anything not turning out well, and the materials seem to have their own will too…
Although not very high Dmax, this outdated Emaks paper produces a nice warm glow with palladium toning.