Archive for June, 2010

Green from blue

June 29, 2010
Iris petals

Iris petals

There is a remarkable medieval green ink that is pretty easy to prepare – as long as you’ve got some blue iris flowers handy – and that is iris green. This color is one that has been associated with sap green, the classic watercolor made from buckthorn berries, but iris green may actually have preceded sap green in use. At some time iris green was even called sap green. It’s been written that it is essentially impossible to distinguish one from the other in old manuscripts; but the bright, delicate greens I’ve been able to get from iris flowers I prefer to the olive greens I’ve gotten from buckthorn.

As I’ve posted here, I am growing some heirloom iris plants in my garden plot, and after a year and a half of care they began to bloom this spring. My irises are more on the violet side of blue, but this doesn’t seem to make much difference. In fact, my irises have a lot more dye in them than the irises I bought at the nursery last year for my first test. There’s something to be said for growing heirlooms. Here’s the procedure:

Cooking iris petals

Cooking iris petals

We’re making ink, so you want to make sure the dye is pretty concentrated in color. After chopping the iris petals into medium-sized pieces (Yes, you have to destroy the pretty flowers – I wish I could simply use the flowers after they have dried, but it just doesn’t work as well), split them into roughly equal parts. No need to be exact. Put one half into a small saucepan and cover them with distilled water. Steep or simmer them until most of the blue or violet color is gone from the petals, then strain them from the liquid, which will now be a pretty rose color. This should take a half an hour or so. Once you’ve strained the first batch of petals out, then add the other half of the petals to the bath and repeat the process. Splitting them up and adding them sequentially to the same small amount of water allows for a more concentrated color right off the bat.

Filtering the dye

Filtering the dye

Once you’re done with this, you should have a liquid that is a nice deep purple, deep enough so that you can’t see through it. You’ll want to filter it at this point to remove any petal debris, bugs, pollen etc. The setup I use is a really simple one: just a funnel (you can get these at Wal-Mart or any auto shop) and an ordinary basket coffee filter. I wet the coffee filter a bit before using it: already being wet, it doesn’t soak up as much of the dye. To collect the liquid I use a Mason jar, which will handle hot liquids pretty well – the last think you want is for your precious dye to crack the jar and spill all over the kitchen! – but even so, if I’m patient enough, I try to allow the liquid to cool a bit before pouring it in, cool enough to dip the tip of my finger into it.

Even with what is almost entirely liquid, the filter can get clogged and go slowly. Once it’s finished, you have your filtered dye. If all you want is a purple ink, then you can stop here; but the magic of iris flowers is their ability to make the medieval green. Purple can be had from many different natural sources.

Iris dye

Iris dye

To the right is the color of the dye as it is at this point. The next stage will be to add alum to it – the alum is what gives it its green color. Alum, or potash alum, is aluminum potassium sulfate, a crucial ingredient in dyeing and lake pigment production. It’s been used in dyeing and pigment making for – well, for quite a long time now. It’s also used to make pickles and maraschino cherries. Apparently you used to be able to get the stuff just about anywhere: the spice aisle, the pharmacy, etc. Perhaps if you live in a more rural part of the country you still can. I buy mine from an online dye supply shop. I’ll go over this stage in the next post.

The material basis of art culture

June 22, 2010

About a week and a half ago or so, soon after I’d made my last blog post about synthetic organic pigments, I noticed an article that ran in the Business section of our local newspaper (yes, the physical kind). It was titled Oil Is Everywhere. (The article is online here.) Since it was relevant, I became interested and looked through. Here is a quote:

Oil is everywhere. It’s in carpeting, furniture, computers and clothing. It’s in the most personal of products such as toothpaste, shaving cream, lipstick and vitamin capsules. Petrochemicals are the glue of our modern lives and even in glue, too.


“It’s the material basis of our society essentially,” said Michael Wilson, a research scientist at the University of California Berkeley. “This is the Petrochemical Age.”

Well, all I can say is that it’s about time someone noticed.

Gasoline is what tends to come to mind when we think of petroleum, but it is only one of the many, many products made from it. The stuff really is everywhere. To see that this is true, we artists need look no further than the materials we use today in the creation of our art. If petroleum is the “material basis of our society,” then it is also the material basis of our art culture. Not only are the synthetic organic pigments discussed in the previous post made from hydrocarbons, but so are modern varnishes, modern “gesso” for our canvas, mediums, inks, dyes, mineral spirits (solvents), paintbrushes, and acrylic and alkyd paints.

In the long term, none of these – nor any other petrochemical product – can be considered sustainable. The current abundance of petroleum is a short-term accident of history and geology; one day its production will decline (or perhaps before that time we will simply decide to quit using so much of it for environmental reasons, but I’m not holding my breath). When petroleum production declines, so will our current art culture.

If you took away our petroleum-supplied art products, many of us would hardly know how to paint any longer. If the modern synthetic inorganic pigments that have only ever been made with hydrocarbon-driven industrial processes were also taken away, we’d be in dire straits indeed. We’ve lost much of the knowledge that would allow us to paint effectively and expressively with simpler materials – “Old Master” knowledge, if you will. Such is the extremity of our reliance upon the industrial machine in this age. Art has always been coupled with industry, since ancient Egypt at least, but now art is almost wholly dependent on it.

Of course, when peak oil passes and world oil production begins to decline, the world will be busy with far larger issues than those revolving around the tiny art materials industry. But personally, I can’t help caring what becomes of our art culture. I don’t want our knowledge of natural and homemade materials to deteriorate to the point where we no longer know what to do without the modern industrial products. This is one reason – one of many, now – that I’m on this path.

Pigment categories – part III

June 6, 2010

I’m going to finally get around to tackling that last category of pigments, the synthetic organics. There’s probably a reason for my tardiness: this is my least favorite group, and one that interests me very little these days. Recall that the three we’ve done before were: natural inorganic (these were the earths and natural minerals); natural organic (lake pigments, other pigments that come directly from plants and animals); and synthetic inorganic (the great chemistry accomplishments of the nineteenth and twentieth centuries, ultramarine blue, cadmium red, etc.). The story of the last category begins in the nineteenth century, but is mostly a twentieth century phenomenon.

Synthetic organic pigments - watercolor

Synthetic organic pigments

To the right are a few quick watercolor swatches using synthetic organic colors. Along the top row, left to right, are: Winsor & Newton manganese blue hue (it’s phthalo blue PB15); Sennelier lemon yellow (hansa yellow PY3); and Da Vinci alizarin crimson (it isn’t: it’s quinacridone violet PV19. Aren’t these marketing names great?). On the bottom row are a couple of mixtures from the three, a bright green from the phthalo and hansa, and a warm red from the hansa and quinacridone. I didn’t include a violet, since this particular red and blue don’t make a very saturated one; but to get a nice bright purple one need look no further than another synthetic organic, dioxazine violet. (The photograph was taken when the paints were still partly wet, and it captured the colors only tolerably well; the hansa yellow in particular is a bit warmer and more transparent than it looks here. Photography is definitely a skill I need to catch up on.)

There are so few real natural organic pigments in use any longer – mostly just the various carbon blacks – that the word “synthetic” is generally dropped from the term “synthetic organic,” having no other category to make it necessary; and these colors are simply called “organic,” since they by and large are the only organic colors out there. The name is a bit misleading at first. Most of us tend to feel a bit fuzzy when we hear the word “organic” – after all, usually it means healthy; it means natural; it probably means eco-friendly, cage-free, free-range, no hormones or pesticides, etc. However, in this case “organic” simply means that the substance in question contains a carbon molecule, and the feedstock from whence it was created probably existed, once upon a time, in the form of actual organisms. I’m talking, of course, about hydrocarbons: petroleum, natural gas, coal, etc. These substances are industrially heated, pressured and combined in various ways, sometimes with industrial acids or other chemicals (my knowledge is very weak on details here), to create the synthetic organic substances. Hmm… my fuzzy feeling has suddenly gone away.

From the Encyclopedia Brittanica: “Synthetic organic pigments are derived from coal tars and other petrochemicals.” By “coal tar” they mean the residue byproduct from burning hydrocarbons such as coal or natural gas. Some coal-tar colors began in the nineteenth century as dyes: mauve, alizarin crimson, the aniline colors – and some of these were laked to create the first synthetic organic pigments. (Some are insoluble to begin with, and don’t require laking.) The twentieth century embraced and expanded upon this line, notably with the azos, the phthalocyanines, the quinacridones, the perylenes, the anthraquinones, the pyrroles.

These are consumer colors – bright and saturated, capable of being produced on a tremendous scale, and cheap. They are truly modern colors, not only in the history of their production, but also in their flash and chromatic glory. Without these colors, the commercial world around us would be much less colorful than it is.

The benefits of these colors for artists are often cited. There is the very full range of color they make available to the artist, the ability to mix almost any color that could ever be needed by the average painter. They have provided excellent, durable replacements for older, less lightfast natural organic colors that have been weak spots in artists’ color wheels for centuries. They are inexpensive compared to some of the synthetic inorganic pigments, such as the cadmiums and cobalts. Finally, they are a less toxic alternative to those cadmiums and cobalts, and are increasingly turned to as the more toxic metals are falling under legislative ire.

So: what’s not to like? Follow me on later posts, faithful reader…