Red chalk - thank you
Thanks to everyone who replied to my question, especially to you, Katharine, for your careful and detailed response which clarifies things wonderfully. FYI I chased down a pigment in the Cornelissen list called "Pozzuoli Red" which seems a little more brick-y than the Venetian red on the same site. Cornelissen declines to allocate a number to the pigment, but a site for icon painters (who insist on natural earth colours) has it, allocates it to PR102 (which would chime with "red ochre" in Hilary Page) and states that it comes from quarries in Northern Italy. I also discover that I've got a small jar of something called "Herculaneum Red" purchased at a wonderful pigment shop in Umbria a few years ago. It's a much more orange colour, and I've no idea whether it's synthetic or natural. The sainted Fred Picker used to get lots of letters from people with queries about various techniques or materials. Many of the senders got their original letters back, with the sole addition of a large rubber stamp saying "TRY IT!". Sounds like good advice - guess I should take it... Best wishes Henry On 24/5/09 22:51, "Katharine Thayer" <kthayer@pacifier.com> wrote: > > On May 22, 2009, at 3:45 PM, Henry Rattle wrote: > >> Recent discussion of Michallet paper prompted me to get a facsimile >> copy of Maskell and Demachyıs ³Photo-Aquatint² paper. They >> recommend a number of pigments for gum printing, Most of the >> colours/pigments they mention are familiar, but second on their >> list of the most suitable, after venetian red, comes red chalk. I >> looked this up on the Web, but only found such things as red chalk >> drawings by (e.g.) da Vinci. >> >> Does anyone know anything about red chalk? Hilary Page doesnıt seem >> to mention it in her lists of proprietary watercolours, nor is it >> in Cornelissenıs catalogue of pigments. > > Henry, red chalk was a red iron oxide (sometimes also called red > ochre) embedded in clay, which made it easy to form into sticks > (chalk) for drawing pretty much right out of the ground, and was also > used as a pigment by some paint manufacturers and called "red chalk" > rather than "red oxide" because of the added clay. This isn't > really too strange, as chalk extenders aren't an unusual additive to > paints, though in this case the clay is a natural component of the > mined pigment rather than something added to the paint to make the > pigment stretch farther. The clay gave a chalky, opaque, solid > quality to the paint that I'm not entirely sure can be closely > replicated by the substitutes available today. No commonly > available paint brand offers this "red chalk" as a pigment. > > Henk's paint sounds like it may be the real thing (and from my memory > of the picture(s?) he posted using it, I am inclined to believe) but > my experiments with various red oxide paints (Venetian red, English > red, red ochre, Indian red, whatever you want to call it) and gum > haven't achieved quite the same effect. You need to look for > something that's as opaque as possible and a deep brick red color. > Unfortunately you can't go by the color name, as paints named > Venetian red range from an almost Mars Violet color through a brick > red to a dull orange-red, and same with paints named Indian red. > Daniel Smith's Venetian Red looks fairly close to the right hue in > the catalog swatch, and is quite opaque, my experiments with it > haven't given quite the brick red chalky look I was hoping for, as > Henk got in his prints with the "red chalk" paint; even in a fairly > heavily pigmented mix the closest I could get was a kind of orange > red, not a deep brick red. And English Red Earth, which I thought > might be another good possibility, turned out to be weaker and paler; > it's opaque but it doesn't have the strength or the saturation of > color that you'd want for this effect. The problem with iron oxide > paints (all earth colors, actually, is that they tend to be weak > pigments and to require a great lot of pigment to achieve any kind of > color saturation. > > As to Mars, in a pigment name Mars means that it's an iron oxide > pigment. > > Very few if any paint manufacturers use natural iron oxide pigments > mined from the earth any more; they're generally made synthetically > now. PR 101, which is the pigment for all the venetian red, red > oxide, red earth, red ochre, indian red, and such-named paints, is a > manufactured rather than mined pigment. So Judy's caution that color > can change from mine to mine is somewhat outdated, but the general > caution still holds that PR 101 (red iron oxide) pigments can come in > different shades of red and orange, and in varying degrees of > transparency as well. > > I think Ken may have had the right idea; since red Conte is indeed > red iron oxide in clay, maybe what we should do, if like me you don't > find a paint that will quite replicate the effect, is to get a mortar > and pestle and a stick of red Conte, and start grinding. The other > place I'd look is in companies that have a large inventory of dry > pigments, like Kremer maybe. > > Hope any of this is useful, > Katharine > >
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