Re: Do different dyes travel at different rates?

This sounds like a very interesting project. You might discover some better or 
cheaper flower dyes than food coloring. 

One student noticed that a yellow food coloring moved faster than other 
colorings but I did not test this myself. I'm sure you could find dyes that 
move at different rates or not at all. I can't guarantee they will all work, 
but here's some readily available things to try: 

1. India ink, which is available at an office supply or art store.
2. A hot water extract of anthocyanins from red cabbage or red onions. 
3. Red beet juice, which contains betalains.
4. Chlorophyll extract in rubbing alcohol or denatured alcohol. 
5. Yellow dye obtained from dry onion skins. It is often used to dye Easter 
eggs.
6. Iodine solution from the drugstore diluted by twenty in water, which is 
used to test for starch.
7. Saffron, a water-soluble yellow spice available at the supermarket. Saffron 
is the stigmas of the saffron crocus.
8. Tea.
9. Bluing, a laundry bleaching compound available at a supermarket. Mrs. 
Stewart's Bluing is a solution of fine blue iron particles suspended in water. 
10. Kool Aid without the sugar. It comes in many colors.

If you have a local florist who dyes their own flowers, they may be able to 
sell you small amounts of the dyes they use.

Scientific supply companies sell a wide variety of stains that you might try 
such toluidine blue, congo red and malachite green. Stains are classified as 
acid or basic. You might see if acid or basic stains travel at different 
speeds.

There are many dyes that can be extracted from plant materials you could test. 

References


Re: why is yellow food colouring sucked up by flowers more quickly?


Stains and Dyes List


Making Natural Dyes From Plants