Re: Artistico Unsized?
Loris, I don't care what anybody says, or how they print, or what they like, no definitive answer to these questions is possible because (in my experience of course) no variable can be isolated... every variable can affect every other variable, so the answer may lie in what combination of variables you're using -- not to mention, what you like in a print.
The only way to "answer" such questions would be in a variable test, or three or five -- do a test strip under the various conditions you envision & see how they look.
That's not just giving 4 coats on unsized Artistico, of course, but with all other treatment and timing the same... and whoever attempts to answer the question in the abstract is living a pipe dream -- especially since ambient humidity and temperature are significant variables.
I myself found that with my usual materials and methods I never did a print without added external sizing that satisfied me. Maybe I lack finesse -- whatever, that was my experience. I'll add by the way that my tests showed that a long (4-5 hours) soak in room temperature water had the same shrink effect as a shorter (half hour) soak in very hot water, which I assume to hold across the board, but I didn't check all variables, so that's an assumption.
For what it's worth, BTW, I note that long ago Mike Ware decided to learn gum printing, tho he chose a color marked Alizarin Crimson and, rather than gum, a particular PVA which I didn't know (and still don't, not having used PVA for gum) but might find the name in the file, if it matters. For whatever reason (maybe it was too easy) he seemed to give it up soon afterwards, but judging from sample test strips he sent me was pretty close. What I didn't understand at the time & still don't is why, given the demanding and exacting tests he was making, he chose a non-archival pigment. I thought maybe he just had the tube on hand, and it was "traditional.