Pigment Palaver: Titanium White

One of the things I enjoy about paint is how the various pigments involved are intimately tied up with chemistry, another of my loves. The properties of a pigment—a substance used to give color to paint—are directly connected to its chemical composition and makeup.

With this post I want to start an irregular series discussing various pigments found in paints both modern and historical. Pigments span all of human history: red and yellow iron oxide are found in cave paintings, are probably among the first pigments people ever used—and yet are still found in paints today. On the recent end of the scale, a beautiful new blue pigment variously called Oregon blue or Yin Min blue (from its chemical composition, YInMn) was only discovered in 2009 and has only just started to come to market in paint form in the past two years. (It's actually not even available commercially in the U.S. yet, only from a paint company in Australia. It's also significantly more expensive than most paint at the moment due to its composition so I probably won't get my hands on any for a while, though I would like to do a post on it.)

One thing I didn't realize until recently was just how many historical pigments used by the Old Masters were actually quite toxic; painting used to be a pretty dangerous hobby! Thanks to modern chemistry, however, we're blessed today with a wide variety of non-toxic pigments with light-fastness and cheapness that the painters of yesteryear could only dream about.

For this post, I specifically want to talk about a relatively recent pigment (brought to paint form only in the 1920s or so), but an incredibly important one to the modern world. In paint form it's called Titanium White, which comes from the fact that it's simply titanium dioxide, TiO\(_2\). Titanium dioxide is estimated to be used in up to two-thirds of all pigments globally, because it has a reach far outside of art: its various properties mean that it's found as a coloring agent in things as diverse as foods, toothpastes, and sunscreen.

Titanium White

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Titanium dioxide is a relatively common, naturally occurring substance. Oxygen makes up the largest portion of the Earth's crust by mass, and titanium follows in seventh place, so it makes sense that their combination is pretty abundant. Common ores include rutile, anatase, brookite, and ilmenite, and global production of titanium dioxide is in the millions of tons each year.

Titanium in general is a very safe metal, biologically speaking. It basically doesn't interact with the body at all, which is why so many implants are made out of it. Its oxide is likewise safe, and is used in all sorts of white food dyes as a result.

The whiteness of titanium dioxide is truly remarkable, reflecting nearly 100% of light falling on it at all wavelengths across the visible spectrum (though it starts to fall off a bit in the ultraviolet). Its reflectance is still high enough that it's used in sunscreens (it's what makes them so white) in order to give them their Sun-blocking power.

This incredible whiteness also makes titanium dioxide useful in paints, where it provides a great opaque white with amazing covering power. It can also be mixed with pretty much any color to lighten it (though it can overpower things if used too much). It's one of the first colors of paint I bought, and it's also the first one I've nearly used a whole tube of so far, showing just how much more of this pigment I use compared to everything else.

Due to its amazing coverage and reflectance, titanium dioxide is justifiably one of the most important pigments in painting, and in the wider world globally. One interesting tidbit of information about titanium dioxide that I couldn't fit in elsewhere is that M-class red dwarf stars are cool enough (only a few thousand kelvins) that they show bands of absorption from it in their atmospheres, adding a heavenly connection to this common earthly pigment. I've used it in most of my paintings so far, and that will likely continue to happen into the future! A hui hou!

(Oh, and I finished my star series of painting this week, so expect a post on them once I get around to getting some good quality pictures of them.)

Musings on Texture Gels in Acrylic Paint

I mentioned in my last post that I'd been experimenting with various texture gels in my painting sessions. I would've expanded upon it then but it would have ballooned the post to much greater lengths than I wanted, so I'm going to note down a few musings on the subject here.

First of all, to be clear (because I've had trouble working out the terminology myself): in acrylic painting a gel is basically a mixture of the base of acrylic paint itself (acrylic polymer emulsion), without any colored pigments added in. It generally dries clear (if it's a “gloss finish”) or slightly milky white (for a “matte finish”). Gels can have various consistencies, but are generally thick enough that you can't pour them. (This is in contrast to mediums, which are still acrylic polymer emulsion, but mixed to a consistency thin enough to where they can be poured more-or-less freely. Gels and mediums can be mixed with paint and each other to get a paint with exactly the consistency you want.)

But back to the texture gels. My only experiences with paint growing up were the occasional practical painting job around the farm, so to my mind, paint was flat: you lay it down in a nice flat layer, and that's it. Painting pictures was therefore just laying colors down in flat two-dimensional layers (sometimes many on top of each other), and that was that. Quite similar, overall, to my experiences with layering in two-dimensional computer graphics.

Only recently have I begun to realize that (part of) the true power and potential of acrylic paint lies in what you can mix it with (which is just about everything except oils), and how that can produce paintings that transcend the two-dimensional surface upon which they sit to rise into the realm of true three-dimensionality. I'd never really thought of paint having texture or three-dimensionality before, but having tried texture gels recently it really is a game-changer. Adding texture to a paint can dramatically increase its presence on the canvas. It doesn't need to be flashy or showy, as even a subtle addition of texture triggers a subconscious reaction that makes the painting look more real by adding realistic shadows to the surface.

There are quite a few texture gels out there already, and it feels like more are being developed all the time. So far I've tried one that gives paint the consistency and feeling of stucco (really fun to work with!), one with tiny resin “sand” grains added (there's also one with real sand), one with ground-up pumice, one with tiny glass beads mixed in (which I mentioned previously), and just tonight a “heavy body gel” that's just a super-thick gel for making paint thicker for more impasto effects (which is the technical term for applying paint thickly enough to make it stand out from the canvas). They're all interesting, and I'm already thinking about trying out some of the other ones I've read about: crackle paste, which deliberately cracks when it dries, modeling paste which contains marble dust and dries into something that can be sanded and chiseled, clear leveling gel (which is really more of a medium, I don't know why it's called a gel) which is very thin and runny and makes paint spread out evenly over a surface…so many new things to try. And it feels like every new technique I experiment with is another tool in my artistic tool box, the combinations of which are rapidly spiraling into a combinatorial explosion of creative possibilities!

Anyway, I should wrap this post up with an update on the star painting series. They're coming along nicely; I worked on some of them for a bit this evening after work with an experimental mixture of slightly larger glass beads and heavy body gel on the two largest stars. I'm excited to see how it turns out tomorrow! Hopefully another few sessions and the stars should be done (most of the smallest ones already are, I think). A hui hou!

Twinkle Twinkle Little Star Painting

In my last post I mentioned that I've been working on a series of seven paintings of stars of the different spectral types on the main sequence, and while I'm still somewhat reluctant to talk about in-progress projects I just came home from such an absolutely amazing painting session that I simply must talk about it a bit, and I'm incredibly excited to get in to uni tomorrow to see how everything looks when it dries.

This entire project has been fertile ground for experimentation. Freed from the constraints of trying to paint something familiar, I've been trying out some of the possibilities of acrylic paint, and the results so far have been mind-blowing when it comes to what kinds of effects you can achieve with paint. Or, with acrylic paint, what you can achieve by mixing in various gels and mediums. Something I've been itching to try for a while are texture gels; acrylic base (basically colorless paint) with various kinds of things added to it to give it a texture, such as stucco, or (natural or artificial) sand, or even bits of pumice.

I've been trying out stucco and resin sand textures in the smaller stars and been immensely pleased with how they came out, as they give the stars an eye-catching but not obtrusive three-dimensionality. Today I tried another texture gel I've been eyeing, one with tiny glass beads mixed in. I used a tiny amount on my smallest star, and the initial results were so promising that I've added it to the next four larger ones. It took longer to dry than I felt like staying tonight so I left it to dry overnight, but I can hardly wait to see how it looks in the morning.

One thing I've been trying for was a sense of dynamism, a feeling that the star is alive as you shift your viewpoint of it, which I've hitherto achieved by using a lot of iridescent medium in the paint to make it sparkle as it catching the light. By embedding tiny glass spheres in the paint layer (and building it up to be a bit more 3D) I'm hoping to amplify this effect as they refract light as you move around, and the merest initial glimpse I caught of the potential suggests it should be pretty amazing.

I realize I'm raving about something with no pictures to show for it, but you'll just have to take my word for it for now: this should be a spectacular sight when I'm done with the project. As to when that'll happen exactly I don't know, but it shouldn't be more than a few more weeks at most; I'm feeling better and better about each star, I've learned a ton about the immense possibilities of acrylic paint over the course of the project, and I think it'll really show in the finished product. But for now it's off to bed so I can shorten the time till I can see how they came out! A hui hou!