Friday and dyeing

[altivo]

No, not dying. Dyeing. With colors.

I spent a good chunk of the day cataloging Spanish language kids books. Never a fun exercise, that, but these were really yuck. Books spun off from Hannah Montana and then translated into Spanish. Talk about rotting kids brains twice, there it is. Then there were the High School Musical ones, no better. No wonder no one in the entire US had bothered to catalog this junk before.

Argos' appearance at the library has made it onto the website. Look quick if you want to see, after Wednesday it will disappear.

Now the dyeing. Tomorrow my spinning group is having a session on natural plant dyeing. I chose curly dock (Rumex crispus) as my color source since I happen to have a lot of it around. I also gathered daisy fleabane for a fellow member who is going to make dye from that. We have to chop up the plants and simmer them in distilled water for 45 min. or so, then let it cool and strain. That will be the dyestock, which we pour back into the distilled water bottle to take to the workshop tomorrow. The other thing I'm doing is preparing some small samples of white wool yarn by treating them with a mordant. The mordant is the chemical agent that helps the dyes bind to the fiber. The most common and least toxic of mordants used with wool is alum, but the workshop leader is going to provide samples prepared with that. I plan to do mine with copper sulfate, which produces what are often very different hues from the same dye. With daisy fleabane, for instance, alum yields yellow, but copper yields green. Copper sulfate, or copperas as the old dyers used to call it, is a poisonous substance that was once used in pesticides. It is also known as blue vitriol, and has to be handled with care. Fortunately I have dedicated enamel coated kettles to use for dyeing, so that's not a big problem. Other metal salts sometimes used as mordants include iron sulfate (non-toxic, but it dulls colors rather than brightening them,) and tin in the form of stannous chloride (brightens and intensifies color but it is both toxic and caustic, so no longer used much.) There was a chromium salt used at one time, but I don't even know where to get that one, it's so nasty. (Oh, yeah, I remember, it's potassium dichromate, and you can get it from chemical supply places but not from the pharmacy or grocer.) A few dyes require no mordant, or will work with common chemicals such as vinegar, ammonia, or washing soda.

I'm expecting a rusty yellow or a greenish beige from the curly dock, depending on the mordant. If it works, I'll have photos in a day or so.

Gary will be gone with Rob to a Civil War event all day tomorrow, so I am animal care, grocery shopping, AND get to attend my little class. It's going to be busy.

Comments

[silver-kiden.livejournal.com]

i thought that i read somewhere that you could use table salt for a mordant with some dyes?

[altivo.livejournal.com]

Table salt is used to "exhaust" a dye bath. Since most dyes involve ionic movements, gradually adding salt to the water will force the remaining heavier ions out to bond with the fiber instead. Salt dissolves very readily because it produces two elemental and highly reactive ions, Na++ and Cl--, if I remember correctly.

Salt is used as a helping agent, but I'm not aware of any cases where it takes an active role in the dyeing itself. Epsom salts can probably be used in the same way, but heavier metal ions are usually needed for the mordanting process. Hence the copper, tin, chrome, and iron.

[schnee.livejournal.com]

Na⁺ and Cl^-, actually, but yes. :)

[duskwuff.livejournal.com]

There was a chromium salt used at one time, but I don't even know where to get that one, it's so nasty. (Oh, yeah, I remember, it's potassium dichromate, and you can get it from chemical supply places but not from the pharmacy or grocer.)

Ah, chromium. Shiny, colorful, and toxic as all hell... fun stuff. :)

[altivo.livejournal.com]

I really should get some to experiment with... carefully.

[marzolan.livejournal.com]

Cupric Sulfate is nasty for the fishes... I work with in my research to do etching and we have to be all kinds of careful with the disposal of that stuff.

I'm curious actually if other copper salts would work, (Like cupric chloride (which is green when in aqueous solution) or even some of the organic salts like stearates) and what their effects would be if you have any knowledge of them.

[altivo.livejournal.com]

Probably some of the other salts do work. I forgot all my organic chemistry the minute I walked out of the final exam, so what I know about this stuff is the traditional, tried and true. Those methods rarely venture into the realm of unknown, because if you ruin a month's worth of spinning or weaving in the name of experiment, you might have to go naked. ;p

[cabcat.livejournal.com]

Hey how long do those colours last? I mean before you notice washing or UV fade.

Hey you really go to a lot of effort at the library to entertain kids and get them into reading ^.^

Despite your grumbling you do good work *hugs the gruff horsey*

[altivo.livejournal.com]

Some of the natural plant dyes and other old organic sources are extremely durable. The browns from walnut hulls and the reds from madder or cochineal are nearly permanent. You're familiar with the indigo blues used on denim, I'm sure, so you know how long those last. (Today's synthetic process is more efficient but produces the same chemical compounds found in the natural indigo or woad dyes.) Some will fade in the sun or when exposed to chlorine bleach, others survive even that. Some change color, from bright yellow to tan or green to khaki after a couple of years. Browns and dark reds are usually the most permanent while blues and yellows are more fleeting.

*hugs you back*

[rustitobuck.livejournal.com]

Oooh, I learned something about dyeing.

And other things!

[altivo.livejournal.com]

Always glad to offer information. Other things?

Watch for a photo, perhaps yet tonight. It was very colorful today.

[merik.livejournal.com]

The mordant is the chemical agent that helps the dyes bind to the fiber.

Interesting! I'm going to have to read more about this, because maybe I'll be able to work this into my lectures on transition metals in a couple of weeks. I always like to try to talk about something practical amongst all of the theory, and this is something none of my students is likely to know anything about.

Oh, yeah, I remember, it's potassium dichromate, and you can get it from chemical supply places

Or from the half-kilo or so I have in my chemical storeroom, along with all the other metal salts you mentioned ;-) I actually played around with chromium trioxide in my lecture yesterday (even more toxic than potassium dichromate, but I'm safe in the small quantities I use... I think), a lovely purple-colored chromium salt that, when introduced to methanol, rips electrons off of the methanol molecules with such energy that the alcohol spontaneously combusts. Lots of sparks and flames, which students always seem to get a kick out of. But probably not such a good metal salt to use in dyeing *chuckle*.

[altivo.livejournal.com]

Mmm, now that's interesting. No, not the flames and explosions part, though I know you're right that today's students probably prefer that to more practical demonstrations.

I have wanted a more detailed chemical explanation of just what those metal salts do to protein fiber to make them take up colors from dyestuff. Haven't found one yet, so if you do located something practical, please let me know. The dyer's manuals, of which there are hundreds going back to the middle ages and before, often have no explanation (probably because the writers didn't know themselves) and just say "Use x amount of copperas in a gallon of water to prepare one pound of wool for dye."

We did have a very colorful day today, and I'll be posting a photo possibly yet tonight.

(Indigo, which requires no mordant and will color nearly any fiber, is a different process entirely. Like henna, it coats the fiber with pigment that will gradually rub or wash off over time. The indigo process I understand.)