What is a mordants?

Katherine, what is a mordants? Something that helps perserve the
color? What ratio do you use?

Sharon Perdasofpy

Yes, you’re right, mordants are used to help preserve the color, and
some can even intensify the color. When most people think of mordants,
it is generally in the context of fabric dyeing, in order for yarn to
hold onto colors without leaching when washed, or is some cases to
help clarify a color and make it more vibrant than it will be
otherwise. It’s an old-fashioned word, which has gone out of common
useage in today’s world. It used to be commonplace even in old
cookbooks, as mordants (salt, alum and vinegar) were used to preserve
color, flavor and texture in canned goods, such as pickles. Etching
solutions are also called mordants in the art
world, but I’m not sure why.

Hi all,

 Etching     solutions are also called mordants in the art world,
but I'm not sure why. 

“… from Middle French, present participle of mordre to bite, from
Latin mordere” source: Merriam Webster.

Ferric Chloride is a mordant and not an acid.

David Popham

Hi to all orchidians!

Mordants = the biting ones from the french word “mordre” which means
to bite.

Have a gorgeous summer 2001! Poidi

Etching solutions are also called mordants in the art world, but I'm
not sure why. 

It is because they “bite” into the metal. Mordant means “biting” in
French (from the Latin “mordere,” if you want to get technical.) I’ve
never heard of any other meaning, except for figurative use, as in a
“mordant remark.” How can you use mordants to brighten color or
preserve it on metal? --Noel

How can you use mordants to brighten color or preserve it on metal? 

I quote from my dictionary, Webster’s Universal College Dictionary–
mordant, adj. 1. sharply caustic or sarcastic; biting; cutting: [as
in] mordant wit. 2. burning; corrosive. 3. having the property of
fixing colors, as in dyeing. --n. 4. a substance used in dyeing to fix
the coloring matter. 5. an acid or other corrosive substance used in
etching. --v.t. 6. to impregnate or treat with a mordant…

In the case of fixing colors, whether it’s dyeing yarn, preserving
the color of cucumbers for pickles, or patinating metal, mordants (not
the etchant type, but the salts, alkalis and acids added to coloring
agents, such as liver-of-sulfur) can serve to intensify, clarify and
provide more durable color, than just the coloring agent by itself.

Some of the typical mordants used in patinating metal aRe: ammonia,
salt, sodium bicarbonate, epsom salts, vinegar and lemon juice. A note
of caution: an alkali and an acid should never be used together, as it
results in a very stinky mess, particularly if you’re using
liver-of-sulfur. Remember your science project as a kid, making a
volcano with dirt, mixed with baking soda, and adding a little
vinegar?

I hope this clarifies without being considered a mordant remark.
Smile!