something weird…

white maple leaves

While out walking today at lunch I spotted this odd group of leaves – each one completely white. The leaves higher up were normal, as were all the leaves on the other maples around. Something fantastically botanical was going on, but I have no idea what.

Perhaps, the explanation lies in the location – the area is called Mystic Vale.

some eggy tidbits

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Both of these chicks turned out to be hens.

The longer days have resulted in a glut of eggs around here – hens I had thought were well into henopause have started laying again, and a chick I got last year that left me wondering if it was a rooster has proven she is a hen (I’d happily keep a rooster, except that in my urban area that wouldn’t be fair to my neighbours). With extra eggs in the fridge, I’ve been thinking a lot about eggs.

Ever dropped an egg? It turns out an egg can be repaired – good news for Humpty Dumpty! Even better news for a Kakapo egg as these ground dwelling parrots are critically endangered. Here‘s a story about an accidentally crushed Kakapo egg that was repaired, then hatched.

Or, considering Easter is approaching, how about natural egg dying? These natural, homemade dyes look great – especially the blues and reds. Beet juice creates a great red/purple/pink range of colours. Perhaps not really appropriate for dyeing eggs, crushed cochineal insects also produce a great and non-toxic red dye that is found in all sorts of processed food. As a slight tangent – up until roughly the 1950s, cochineal was the dye used for British army uniforms. This dye gets listed under a number of different names such as ‘natural red 4’ or ‘red #40.’

In general red colouring in food causes me some concern, a while back I took a look at the surprisingly long list of red dyes in a brand of iron pills that my doctor recommended I take. I have no biological need for cadmium, yet it could be found in those iron pills (among other unnecessary things). Apparently, cerium can be used as a non-toxic alternative to cadmium. However, I’ve since found iron pills with no colouring at all.

As a final note: check out these finches playing the guitar.

Fireflies

Few insects vie in popular fame with the glow-worm, that curious little animal which, to celebrate the little joys of life, kindles a beacon at its tail-end. Who does not know it, at least by name? Who has not seen it roam amid the grass, like a spark fallen from the moon at its full?

– from The Insect World of J. Henri Fabre, an anthology of Jean-Henri Fabre’s works translated from French by Alexander Teixeira de Mattos.

Glow-worms, also called fireflies or lightening bugs (I prefer to call them fireflies), don’t live where I do, so I’ve never seen one. My only encounters have been in fictional accounts, but I can understand how they capture people’s imagination – I’d be captivated if glowing beetles ‘like a spark fallen from the moon at its full’ were flying around my backyard. I suspect I’d watch them for hours, and back when I was a kid, I would have loved to catch them. According to the Smithsonian Institution’s Animal; the Definitive Visual Guide to the World’s Wildlife, 2000 species of fireflies exist world-wide, ranging in size from 0.5 to 3 cm. And it’s no surprise that they’re typically nocturnal; what would be the point of glowing if no one could see?

Their light serves different purposes through a firefly’s life. As larvae, they flash to warn predators of the larvae’s toxicity. As adults, each species emits their own unique set of flashes to attract mates. Males typically can fly around to find their mate, while the flightless females stay in one place and flash. A female firefly’s flashing can be the downfall of a male, since some females mimic other firefly species’ flashes to earn themselves a quick meal.

A firefly’s light falls into the 510 – 670 nm range, corresponding to yellow, green or pale-red and contains no infrared or ultraviolet wavelengths. They produce their light purely through a chemical reaction that triggers a light-emitting pigment to flash within specialized cells in the firefly’s abdomen.

Firefly populations are decreasing. Loss of habitat makes life harder for fireflies, and light pollution may be interfering with their signals. In fact, light pollution causes all sorts of havoc for critters. For fireflies finding a mate becomes more difficult, because how can they home in on a series of flashes from a potential mate while lights are flashing all around them? For other animals excess light confuses their sense of navigation, like puffins in Iceland disorientated by city lights. Children rescue the puffins and release them – which strikes me as a bit odd since puffin is considered a delicacy there. Light pollution is such an issue (probably more because it make the stars hard to see than what it does to critters) that there is an ‘International Dark-Sky Association’ and places designated ‘dark-sky preserves’. I wonder what all the excess artificial light is doing to us?

Lots more info about fireflies can be found here.

And now for something yellow

Turmeric stains – a fact that is made clear to me every time I make curry and a drop ends up on my light coloured counter tops (what were the previous owners thinking when they installed baby blue counter tops?). Turmeric seems to stain more than any other spice I use, why?

First, a bit about turmeric. Native to South Asia, turmeric plants thrive in the moist, hot conditions found there. It’s a member of a tasty family including: ginger, galangal and cardamom. The name ‘turmeric’ may originate from the Latin terra merita, which means merit of the earth. The turmeric powder commonly used as a spice is derived from the rhizome, a horizontal stem that typically grows shallow beneath the soil. From this stem, roots and shoots are sent out. These rhizomes are harvested about nine months after planting, then boiled, peeled and dried in the sun. Once dry, it is ground into a power.

About turmeric, Marco Polo said “There is also a vegetable which has all the properties of true saffron, as well as the smell and the colour, and yet it is not really saffron.” In medieval Europe, this spice was called ‘Indian saffron’ and was commonly used as an alternative to the expensive saffron. According to ‘The Flavor Bible‘ turmeric has a bittersweet pungent flavour. Today it’s commonly used to make mustard yellow, and as a component in curries that adds both flavour and colour. At times, turmeric even been used to colour cheeses, margarine and chicken broth. I wouldn’t mind at all if turmeric was used as a colourant in my iron pills because it can do some good. In fact, a long list of potential medicinal uses have been attributed to turmeric, one use that has been proven is that it reduces inflammation.

Turmeric’s use as a dye probably dates back as long as it’s been used. I can’t imagine not to noticing that turmeric stains cooking implements once it’s added to a dish, however, the first record of using turmeric as a dye comes from an ancient Assyrian herbal recipe dating back to 600 BC (a fact from The Cook’s Encyclopedia of Spices). The yellow colour is caused by curcumin, a chemical component of turmeric. About 5% of the dry powder is curcumin. The colouring components of other spices like paprika are less than 1%, so, to answer why turmeric stains more, there is just more colouring potential in the turmeric. On the plus side, turmeric fades in sunlight – so if a drop of curry ends up on a favorite white shirt put it in the sun for the colour to fade.

Bloody colours

To a bloody war and sickly season – the traditional Thursday toast of the British Navy.

Since I’ve already written about blue (here and here), a friend suggested I write a post on redder colours, specifically ones named after bloody battles. I only found two: magenta and solferino – both are purplish red colours, perhaps even the same colour. Magenta and Solferino are both towns in Northern Italy that were caught up in the second Italian war of Independence at the same time synthetic dyes were being made from coal tar for the first time. Magenta as a colour name is still in common use, while Solferino was the more important battle. A witness to the battle of Solferino, Henry Dunant, found it so horrible he began a campaign that ultimately resulted in the founding of the Red Cross.

In 1859, Emmanuel Verguin’s experiments with aniline dyes (ie the ones from coal tar) resulted in a rich crimson red. He called the colour fuchsine after the fuchsia flower and it was an instant hit. This was a prominent colour of the uniforms at both the battle of Magenta and Solferino, both in June 1859, so I don’t know if the colour took these names because of the uniforms or the bloodiness of the battlefields (I’ve found references both ways). A few years later, the colour’s name was once more changed, this time to rosaniline, but magenta is the name that stuck. A arsenic acid oxidation process was required to make this dye causing some of its wearers to be poisoned – leaving magenta even more bloody. (For more details of synthetic dyes ‘Mauve’ by Simon Garfield is a good read)

If you took a good look at the colour spectrum of light, magenta wouldn’t be found. Magenta is considered an extra-spectral colour because it cannot be generated by a single wavelength of light. It is formed in our minds when there are equal parts of blue and red light (in truth colours only exist because our brains perceive them).

Making Blue – part 2

Further to my last post, another synthesized blue lurks in my paint box – Prussian Blue. It is a complex dark blue pigment that was first synthesized around 1706 by the paint maker Diesbach (whose first name I couldn’t find) in Berlin. Since its discovery, Prussian Blue has been used extensively in making paint, and is the traditional “blue” in blueprints. Strangely, It has been used as an antidote for certain kinds of heavy metal poisoning – perhaps a story for another day.

The synthetic Prussian Blue filled a gap left by the loss of knowledge of how to make Egyptian Blue. It is a stable and relatively light-fast blue that is cheaper than ultramarine made from lapis lazuli. Artists were waiting for a pigment like this, so within two years of it’s discovery it was already being traded across Europe. Prussian Blue is a strong colour that tends towards black or dark purple when mixed into oil paints. Interestingly, the particle size of the pigment creates the exact hue.

Prussian Blue is a complex chemical including iron and cyanide. It’s not particularly toxic because the cyanide is bound tightly to the iron. I was surprised to learn about the number of applications where this pigment is used. In medicine, Prussian Blue is used to detect iron in biopsies like bone marrow. It is also the basis for laundry bluing, that is, it’s used to add a slight hint of blue to someone’s washing to combat yellowing of whites.

Once children’s crayons contained a Prussian Blue, but now that has been changed to Midnight Blue. It has been a long time since I’ve looked at crayon colours – I think the last time was when I melted them to colour wax for candle making.

Making Blue – or what to do if you don’t have enough lapis lazuli

‘Through the atmosphere the universe tones towards us in the colour blue and according to the thickness of the air, takes on every grade of blue until it goes over to black-violet on the mountain tops’

-Goethe ‘Theory of Colours’

The above quote makes me think of the Van Gogh painting ‘The Starry Night‘ – one of my favorites. I love the shades of blue (I love the swirls too but, that makes up a different story). So what makes paint blue? Typical pigments used include Azurite, Cerulean Blue, Cobalt Blue, Prussian Blue and Ultramarine which was once made from lapis lazuli.

Although there are other natural blues that can be used in pigments, lapis lazuli intrigues me the most. Years ago, I read a book on natural colours where the author journeyed to Afghanistan (in safer times) to find lapis lazuli. I don’t have the book at hand, so I can’t quote from it, but ever since then I’ve thought lapis lazuli had a fantastic story, I even like saying ‘lapis lazuli’. Powdered lapis was used as eyeshadow by Cleopatra – what could be more exotic than that?

Lapis lazuli has always been prized for its intense blue color. It has been mined from Afghanistan for over 6,000 years and there are other sources around Lake Baikal in Siberia. Lapis lazuli is classified as a rock composed of more than one mineral. Since it polishes well, it can be made into jewelry, carvings, boxes, mosaics, ornaments, and vases. In ancient Egypt, lapis lazuli was favored for inclusion on amulets and ornaments such as scarabs. To answer my paint question, lapis lazuli was also ground and processed to make the pigment ultramarine.

So what if lapis lazuli wasn’t available (or too expensive)? Before modern synthetic colours became available there were several options.

Egyptian Blue is a pigment that was made and used by Egyptians for thousands of years and may even be the first synthetic pigment. In Egyptian it’s called ‘hsbd-iryt’, which translates to ‘artificial lapis lazuli’. Although it’s only one of many components, copper is what makes Egyptian Blue blue. The exact hue of blue can range from light to dark depending on how it is made. Egyptian Blue coloured stone, wood, plaster, papyrus, and canvas. It was also used in objects like cylinder seals, beads, scarabs, inlays, pots and statuettes. Unfortunately, when the Roman era ended, knowledge on how to make Egyptian Blue was lost. Egyptian blue has been found on objects from all over the Roman Empire and may have been independently discovered in places like ancient China.

At least 2,000 years ago a synthetic blue turned up in China. Chinese Blue and Egyptian Blue have the same basic structure and have very similar properties. The difference is that Egyptian Blue contains calcium where Chinese Blue has barium. Was this Chinese Blue produced from knowledge of Egyptian Blue making it’s way along the silk road? There are theories that lean both ways.

Another ancient blue comes from pre-columbian mesoamerica and examples are still blue today. Maya Blue is a organic-inorganic hybrid that was made by heating indigo and a fibrous clay together. This method worked so well it is an active area of research today.

Back to lapis lazuli. Lapis lazuli’s use as a pigment in oil paint ended in the early 19th century when a chemically identical synthetic variety, often called French Ultramarine, became available.

Cadmium

I was working out of my office yesterday, in a building that is basically a line of industrial workshops. I was doing some necessary but messy work and when I was done I swept out my workspace. The floor was dusty and by sweeping I put that dust into the air and no doubt breathed some of it in. It turns out that in one of the workshops at the end of the building is contaminated with cadmium. I doubt that sweeping the floor at the other end of the building exposed me to much, but I have worked with cadmium paints in the past so I did some looking into its toxicity.

Discovered in the 1800’s, cadmium is a metal that has a bluish-silver look to it. It is soft and easily manipulated and can be a byproduct of zinc production. Since our bodies have no use for this metal, it is toxic to us even at low concentrations. To me the scariest part is that cadmium bioaccumulates – there has been reports of cadmium poisoning from crops downstream of mines. Ingesting it over a long period of time can result in kidney disease and various types of cancer – but inhaling cadmium fumes can be fatal relatively quickly.

Even with its scary side, cadmium is interesting stuff. I first encountered cadmium as a pigment component; it makes brightly coloured yellows, oranges and reds that last for centuries without losing their original bright hue. These shades replaced older, not light-fast pigments such as vermilion (mercury sulfide). Cadmium has also been used as a corrosion-resistant coating for steel and as a stabilizing compound in plastics.

Because of its toxicity, cadmium use is in decline. There are now non-toxic replacements for the cadmium pigments, it has been phased out of plastics and many of its other uses. Currently, most of the cadmium produced goes into nickel-cadmium batteries, which leaves a worry of how these batteries are disposed of.