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!

How to Paint A (Specific Spectral Class of) Star

I said in my previous post that I don't like revealing projects in progress, but my current project is so cool that I can't resist. Plus, it's more like a series of projects so I don't mind revealing one that I've completed.

I've decided to do a series of seven paintings of the various spectral types of stars. I'm only doing main sequence stars for now, as this allows me to paint them all to scale and I love those kinds of visual comparisons. (People keep asking me about other types of stars such as white dwarfs or supergiants, and my response has been a firm “We'll see.” I can't really paint those to the same scale so I don't think I'd be able to do them justice, but perhaps something will come up.)

This past Wednesday I painted the second star in the series, a B-type star, and had the idea of filming the process to make a time lapse video of it. It came out so well that I decided to add some commentary explaining my creative process, since it's informed by things like thermodynamics and stellar structure (while still retaining a fair amount of artistic license, of course).

Anyway, here's the video! Painting while conscious of being filmed was an interesting challenge, but I think the finished product is pretty good. Enjoy!

Healesville Sanctuary Trip the Second

Well, it's been nearly a month since my family departed back to California and things have mostly settled back into a familiar routine. I was a bit trepidatious about getting back to work on my research after a month away, but it turned out to be surprisingly easy to pick up where I'd left off; I think the re-writing of my code I've been doing after the SciCoder workshop in November has paid off with more easily-understandable and maintainable code. Our weekly art workshops at Swinburne have resumed and I've gotten back into painting regularly again; I've picked up a bunch of new paint and painting supplies and I've got several exciting projects in progress and ideas for several more, but I'm going to wait till they're finished before showing them off here so that'll be a post for another time!

For today, though, I have a few pictures from the trip we took to Healesville Sanctuary:

Here's one of an endangered Regent Parrot eating out of a dish I'm holding in one of the several aviaries at the sanctuary.

And here's a Red-Tailed Black Cockatoo!

This is an echidna, something I don't remember seeing in my trip to the sanctuary last year. This one was pretty funny, as for the entire time we watched it never stopped waddling around its enclosure (for what reason we were unable to determine).

And finally, me with some native Australian fauna I found in the gift store on the way out.

I've got a lot more pictures to go through so there are more coming, and hopefully I'll have the next ones up with less of a wait in between. A hui hou!

Personal Panoramic History, Part 9: 2016

I originally wrote this post to go up at the end of December, and had it all ready to go, then forgot to actually post it. Then January flew by in a whirl with my family around, and I've finally got enough time to see about properly posting it.

In the previous post in this series, 2015 was a pretty slow year for me regarding panoramas, having only made a total of six and concentrating them into two months of the year. 2016 was a more varied year, where I still only made seven panoramas but spread them out more evenly to about one a month.

February

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Mauna Kea summit, from the entrance of the JCMT.

February's panorama is a common theme, the summit of Mauna Kea. This is taken from just outside the entrance of the James Clerk Maxwell Telescope, looking from north to east. You can see all the telescopes on the mountain at the time except for the Submillimetre Array (off to the left), the JCMT (behind me), and the Very Long Baseline Array radio dish further down the mountain.

March

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West end of Puʻu Huluhulu.

I'm pretty sure this is a panorama, based on the file size and perspective effects. (It's definitely not one I assembled out of multiple photos, so I'm thinking it's from my phone camera.) I posted almost this exact picture, except cropped, in a post from 2016. This is the west end of Puʻu Huluhulu, a small eruptive cinder cone near the start of the Mauna Kea and Mauna Loa access roads. I took this picture because I was interested in seeing how the overlying volcanic “crust” had been thrust up by the explosion that created the puʻu, which I talk about more in the linked post.

May

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I never uploaded this panorama before because it didn't turn out all that great—the Sun's flaring on the left and it's pretty dark in places otherwise. It's from a park pretty close to my house in Hilo, where what I think is a little offshoot of the Wailuku river flows serenely by. Some of the foliage, especially in the center foreground, is captured pretty nicely at least, even if the overall contrast range didn't work out too well.

June

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Experimenting with getting a good contrast range was the theme for June, as I took three panoramas with my phone camera, all from atop Puʻu Kalepeamoa looking up towards Mauna Kea at sunset:

The first one came out way too dark, as the camera focused on exposing the white clouds and blue sky.

The second one came out better. The clouds are blown out now, but you can still see a bit of blue in the sky while simultaneously being able to make out details in the shadowed areas.

The third one swung a bit too far into overblown territory, though at least the detail in the shadowed areas can be seen quite clearly now!

While writing this post I had an idea to see if I could somehow merge the three together to get an image with high dynamic range, but unfortunately the perspective shifts enough between them that it's impossible to get them to line up correctly.

July

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In July I took a trip to a night market down in Puna the name of which I've unfortunately forgotten (“Uncle Roberts,” maybe?). It was located down by the beach, which allowed to get this…very strange looking panorama at sunset. No, that's not some distant tsunami causing the water on the horizon to bulge up like that, it's just what my phone camera made of it. Wish I'd been able to get a better panorama, as it was a nice rocky beach and a beautiful time of day, with the water all foamy on the strand.

September

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In September I took another trip to Volcanoes National Park and hiked the Kīlauea Iki trail for the third time. As per tradition, I took a few panoramas while I was there:

The first is from my phone camera, and illustrates a problem I've often had trying to get pictures within the Kīlauea Iki crater. Namely, the lava rock is so dark black that it's really difficult to expose both it and the sky at once. I'm sure it's possible, but my phone camera wasn't able to pull it off. I never posted this panorama as I wasn't happy about it for that reason, but looking at it now I find I rather like it. Sure the sky's blown out, but the rest of it's actually a pretty good representation of Kīlauea Iki from the eastern end.

The other panorama is one of the more rare vertical ones, and this one is hand-created from a few photos I took with my DSLR. (I've found Hugin doesn't necessarily handle these vertical ones that well.) This area is at the foot of the mountain of cinder and rock on the south-western edge of the crater, where the lava erupted from. I'm not sure why it's so much greener than the rest of the crater floor; perhaps water channels or pools here better? Or since it's more cinder and less unbroken rock, it's easier for plants to get a roothold? Whatever the reason, it's a little oasis of green in the black rocky desert.

And that's it for 2016 panoramas! In 2017 I get my second job working at over a mile high, so there will be some really nice panoramas, though it'll still be about the same number overall. A hui hou!

A Painting of Squeaky Beach

It's been a quiet month here on the blog (happy 2019 by the way), because it's been a busy month for me: my entire family came to Melbourne to visit for two weeks, and I've been back and forth over quite a lot of Victoria during that time! I've got a lot of pictures (and some videos) that will take some time to sort through, which should mean content for a whole series of posts in the weeks to come.

I'll just put this one up for now, a picture of a painting I was inspired to make of Squeaky Beach at Wilsons Promontory, a peninsula at the southernmost tip of the Australian mainland:

“Squeaky Beach” (Named for the sound the sand makes. A late Christmas gift for my sister and brother-in-law.)

It was a pretty neat beach, but I'll probably discuss it more later, so for now, just admire that ocean! I'm pleasantly surprised at just how well it came out, how dynamic it appears. I used a number of different shades of blue, blue-green, and even purple to try to help capture that continuously varied color the sea has. Also I think the seagulls—of which there were many at the beach—came out pretty cute, too (if such a thing can be said of seagulls).

I really enjoy watching the waves crash against the beach and trying to capture that makes for a fascinating painting challenge, so I can definitely see myself coming back to such scenes in the future. Anyway, that's enough for now, as tomorrow it's back to grad student life! A hui hou!

Happy 2019! Hauʻoli Makahiki Hou!

Well here it is, 2018's just about over and 2019's just around the corner. A year spent in Australia, a year spent below the equator—and now that I'm west of the international date line instead of east I get to welcome the new year before most of the world instead of after it. (Which means this post is going to go up the day before for people in the U.S. Oh well. That's time zones for you.)

And I'm off to a New Year's party now, so see you all in 2019! Hauʻoli Makahiki Hou!

A Christmas Eve Astrobite

I've put up a final post on Astrobites this year, on Christmas Eve, of all days! Especially after posting one on Thanksgiving. This is actually the post I wanted to write for Thanksgiving, but time constraints and the fact I already had one half-written changed that.

This paper is about how our Sun is so incredibly stable in brightness over time compared to other stars. In fact, its variability is so much lower than other stars that it's been a long-standing puzzle in solar physics. To explain it briefly, the authors of the paper I wrote about did some simulations of Sun-like stars while varying a few key parameters such as the proportion of elements besides hydrogen and helium and the star's effective temperature. What they found is that the Sun sits in a very special place in phase-space where it ends up being almost perfectly constant in brightness over the course of its solar magnetic cycle. Changing the metallicity or temperature by extremely small amounts (relatively speaking)—in any direction—causes the variability over a star's magnetic cycle to shoot up dramatically.

(The mechanism I thought was pretty interesting: magnetic activity in stars causes two types of phenomena, starspots which are darker than average, and faculae which are brighter than average. Most stars are dominated by one or the other over the course of a magnetic cycle which changes their brightness, but the Sun's parameters cause the relative numbers of sunspots and faculae to almost perfectly balance in such a way that its average power output as seen from Earth is almost constant.)

This is actually final astrobite as a scheduled author; going into my second year of my PhD I've decided to retire from the active rotation to be able to focus more on my research. However, I'm not done writing just yet! I'll be able to write posts for the queue, and I still intend to, which just means I won't know when they'll go out. I no longer need to write one every month or so, so the number may go up or down depending on how many interesting papers I come across. Honestly, that's the part I'm looking forward to the most: some of my posts were on papers I found genuinely fascinating and loved explaining and I'm really proud of them, while a few of them were written just because I had a deadline and were the most interesting least boring papers I could find recently. Being able to write only when I'm really motivated (kinda like I do here…) is quite an exciting prospect!

I feel like that may have ended up more melancholy than I intended, so how about some Christmas presents? For the featured image for my posts I used the painting below, which I painted last Thursday as a present for my adviser:

“A Solar Twin,” by me.

(Unfortunately I miscalculated when he was going on vacation so he'll find it when he gets back in January, I guess. Some of my friends were ribbing me that I'm setting unrealistically high expectations for the other students now!)

Painting a star turned out to be so much fun that I painted another one the next night, a pulsar for my associate adviser:

“A Pulsar,” also by me.

Ignore the ugly shadow cast by my easel at the top of the picture. Which, I realized, I haven't mentioned yet, so yes, I bought an easel! I feel like a real artist now. An easel makes painting so much easier. I picked one that's quite portable and folds up nicely so I can bring it home (as I've done over the break, along with my painting supplies). It's sitting in the corner with my current work on it, and I must say, an easel with a painting in progress on it really classes up the room it's in!

Anyway, that's enough for tonight. Merry Christmas everyone, and I hope to be back with some more posts soon now that I'm on vacation.

A December Update

It's been pretty quiet on the ol’ blog front this month—for a few reasons—but I'm hopeful that'll change in the next week or so. First off, I got sick last weekend, which laid me out for almost a week. Then, I've been struggling with a lot of instability in my computer the past few months, which I finally tracked down to one of my RAM modules starting to fail. I found and removed it last weekend, and my computer's been nice and stable again since. And finally, I've just been busy with numerous things as the end of the year rolls around.

This is the last week before the Christmas break begins, and I'll be taking a few weeks off after that, so I'm hoping that starting this weekend I can finally start working on some of the many creative projects rattling around in my head that have been accruing the last few months. And that'll likely lead to some new blog posts, so the second half of December should be a little livelier than the first half has been so far. Blender just came out with a huge new update that radically overhauls the interface to make it simpler and more intuitive, and I'm interested in checking it out to see how it's changed. Plus I've got plenty of other ideas for projects to do. A hui hou!