If you hate the cat on your Tefillin Barbie, you can soak it off with acetone. Acetone is most easily obtainable as nail polish remover. Get the cat good and wet, give it a couple of minutes, and then scrape it off.
hatam_soferet: (Default)
( Jan. 1st, 2009 04:46 pm)
Sofer's inkThe main thing about Torah ink is that it has to be black and it has to stay black. If it changes colour within fifty years, it wasn't kosher to begin with.

Generally, Torah ink (דיו, in Hebrew, like dye) is what's called an iron gall ink. Iron gall inks have been used in a great many places during a great many periods in history. They last a long, long time (think Dead Sea Scrolls kind of longevity). They have an unusual property among pigments in that they form chemical bonds with the parchment, which makes them symbolically very appropriate for use on Torahs. They are lightfast, the ingredients are cheap, and they are very indelible.

I don't make my own; making good ink is hard, and I don't have anyone willing to share their recipe. Anyway, it's supposedly rather a pain, so I buy it in bottles, as shown. I don't know if it's also available in cake form - cake is much easier to transport, of course, and lasts longer, and is entirely traditional. I suspect perhaps not, because I have a feeling that buying ink like this is kind of For Dummies, and real hardcorers, the kind who would want cake ink, probably do make their own.

As you might expect, there are hundreds of different recipes for this kind of ink. However, they have some things in common, viz.: gallnuts, iron (II) in solution, something runny, and something sticky. The following descriptions are indebted to an excellent article by Cyntia Karnes.

Gallnuts on oak leavesGall nuts

See the Wikipedia entry, but basically gallnuts (also called oak-apples) are a sort of arboreal tumour. A gall wasp comes along and lays its egg on the tree, and the tree goes "whoa" and swells up around the egg, into this little hard ball. The larva sits inside the swelling, munching away, and when it grows up it eats its way out and leaves the ball on the tree.

The balls have to be turned into a gloopy solution. This basically involves grinding, dissolving, and fermenting, and there are about a zillion ways of accomplishing this. Depending how it's done, what you end up with is a liquid containing tannic acid, gallotannic acid, or gallic acid.

Iron II sulphateIron (II) sulphate

This is where the iron comes from. It tends to be known as copperas, or coppervasser if you are the Mishnah Berurah, because iron sulphate and copper sulphate tended to come out of the ground together, but the copper isn't important and the iron is.

NailsThis is why some recipes call for boiling up nails with the gallnuts. In an acidic solution, you get the right sorts of reactions. It's apparently quite dangerous if you do it properly.

More about that...and lots else... )
hatam_soferet: (Default)
( Mar. 20th, 2008 09:49 am)
I'm writing a thingum about why Torah ink is particularly interesting, and in so doing needed to learn more about how ordinary inks work. What I learned led me to wonder how permanent markers manage to write on glass and other very smooth surfaces. Which led me to finding out about how different types of glues stick to things, which led me to learning about geckos.

Geckos have really amazing feet.

Which is the message of this post. Geckos: way cooler than you ever thought a gecko could be.
hatam_soferet: (Default)
( Nov. 6th, 2006 09:29 am)
I'm very fond of these diddy little inkwells, and I have several kicking around the place. Today, I found a random one in the fridge (I keep inks in the fridge, cos they can grow mould if you don't). What's in it?

There are only two sorts of ink the mystery bottle can contain, at present, cos I only have two kinds of black ink in the house. One of them is kosher, and I can use it on the Torah, and one of them isn't, and I can't use it on the Torah, and if I do the Torah will be pasul. Invalid. Bad news. I could taste it and work out what it is, but ink tastes vile, sofer's ink more so, so I'd rather not.

Science to the rescue! Colour chromatography.

By way of illustrating the method, first we'll compare two known inks.


Fig 1a: Left: sofer's ink. Right: Brand X ink


Fig 1b: Left: sofer's ink. Right: Brand X ink



You take two strips of kitchen roll, and put a blob of ink near the end of each. Properly, you hang the strips vertically because the reason it works has to do partly with gravity, but for this kind of thing you can just drape them over a plate and it works fine.

Then you dip the ends in water, and see what happens!


The different pigments move through the paper at different rates, and separate out, so you can get an idea of what's in the ink. The sofer's ink mostly stays black, with a sort of pink tinge round the edges, and Brand X goes all kinds of colours - yellow at the top, blue at the bottom. It also spreads much further, because it's more water-soluble (sofer's ink binds chemically to natural fibres) it looks like there's just more of it in the picture, but I used the same amounts - Brand X spreads even before you wet it, that's all).

So, now we can find out what the mystery ink is.


Fig 2a: Left: sofer's ink. Right: Mystery ink


Fig 2b: Left: sofer's ink. Right: Mystery ink

Two blobs on dry kitchen paper, draped over a plate, same as before. Wet the ends...

...and we see no blue, no yellow, only the pink tinge and the limited spread, just like the one we know for sure is sofer's ink. So it must be sofer's ink.

Hooray for science!
hatam_soferet: (Default)
( May. 7th, 2006 11:08 pm)
All right, y'all biochem people - help me understand tanning. You get a skin, and you put it in a lime solution. The lime solution makes follicles very unhappy, and eventually the hairs drop out. Why? What's happening? If the lime is exploding the cells holding the hairs in, why isn't it exploding the cells in the rest of the skin? and if it isn't, what is it doing? Are epidermal cells more susceptible to being exploded by lime? It's been so jolly long since A-level chemistry, and we didn't do tanning, anyway. [livejournal.com profile] livredor, [livejournal.com profile] pseudomonas, help...please!

While we're at it, if I want to split a skin in the plane of the skin, so as to get two thin skins from one thick skin, what's the word describing "in the plane?" I split the skin *****ly. Planarly is not a word.

ETA: Jordan says "laminally" is the word, and Chambers agrees with him. Thanks, Jordan!
.

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