Worksheet on Dyes

Lesson

1. Dyes have been used for a long time. Neanderthals coated their dead with red ochre which was really ________________ (rust). Cave paintings used ____________ and ______________ iron ____________, black ____________ and white __________. Humans got their coloring agents from ___________and ______________until weaving was invented. What is the difference between a dye and a pigment?
   
   
2. One of the most important animal dyes came from the ___________, which formed a ____________ color. The dye was extracted by ____________ the shellfish and boiling them in _________ water for __________ days. Cloth was dipped, placed in the sun, and the color changed to __________ then to _____________. In the beginning only the ____________ could wear it. Later dyes were formed from ________________ and it was a _____________ color. Cochineal was an _________________ and used until 1954 to dye _________________.
   
   
3. Vegetable dyes can be made from plants. The three most important were _________, _______________, and______________. Madder is a ______________ color and the chemical it contains is _______________. Woad is a ____________ color and contains ______________ as its chemical.
   
   
4. What are chromophores? (Look on left of page 6)
   
   When the light of certain colors strikes the chromophores, ____________are energized and the light is _________________________. A good dye must also be ____________ so the solution can penetrate the fabric. Once in the fibers it must become ___________ or attach itself to the fibers, so it does not wash out. The _____________________ dyes that we will use for tie dye are fiber reactive. This means that the dye molecules react with the cellulose (cotton) molecules in the shirt.
   
   
5. Saxon green was a mixture of ______________ and ________________. Indigo is much richer in the molecule. It was called the _______________ and believed to harm both the ________________ and its ______________. The anti-indigo lobby kept the plant out for _______________ years. Finally it was chosen for the British naval uniform and it gave the world ____________ forever after. Today indigo has been largely replaced by other blues EXCEPT it is still used for dyeing _____________________.
   
   
6. A mordant (page 7) is a _________________. It is usually an ion that attaches to both the _____________ and the __________ and forms a ___________ between them. Most mordants are salts of _______________________. Some mordants change the ____________. Alizarin (red) turns _____________ when reacted with ___________, or __________with calcium, and ______________ with ____________________.
   
   
7. Indigo is not soluble in water so is applied by _________________. Indigo used to be treated by ________________ but today they use ________________. The cloth is soaked, then ______________ by hanging it in the air. Oxygen ______________ the indigo back to the _________________ form, which is ________________ and difficult to wash out.
   
   
8. A college student named __________________ made the first synthetic dye named ____________________ as it was a purplish color. In the beginning the ____________ were the leaders in the dye industry, but soon the ___________________ took over.
   
   
9. Today more than _____________ synthetic dyes are available.
   
   
10. Levi Strauss started dyeing ________________ from tents with ____________to make the first ___________________. The heavy gold nuggets ripped out the pockets, so Levi reinforced them with ________________. The word denim came from ___________. Nowadays in denim mills, ___________________ is unwound and passed quickly through _____________________ (yellow) then exposed to air where it turns ____________. This process is repeated as many times as ______________ until the color is jeans blue. The back side of denim is ____________ blue and _____________ white. Roll up your jeans and take a look. Jeans get better with age as the color gets lights and softer. Right? However, stone washing makes them soft to begin with.

The dyes that you will use to tie dye are called PROCION MX and have been around since the 1950s. They are fiber reactive so have a chemical reaction with the cellulose (cotton) in your t-shirt. They became very popular in the ‘60s and were worn by many hippies and young people. However, several times since then, tie dye has come back in style. Enjoy your tie dye!