This is a thread someone posted recently. I sounds like she did what you did. Maybe you could pm her with your question.
http://www.quiltingboard.com/t-145643-1.htm

just a silly thought - did you use crayola WAX crayons?!!

Have you tried color pencils, and you set them with painters medium (I want to say Delta) found in the craft acrylic aisle at micheals not the painters aisle.

Wow!!

plain old crayola crayons...last for many washings/years....

I place the paper towel right on top of the crayon coloring and heat set it...if it looks like I need more color, I do it then......once heat set, I usually do not wash until the piece needs it..which is rarely! BUT I do have some placemats that needed it right away...still...they look great!

You know, I'm not sure. I had my iron set on 'cotton' and I left it fooorrrreeeevvvveeeer! It got really hot, but nothing came off onto the paper towels. . . no wax, no color, although a little color did bleed through to the back of the fabric. The box just says "Crayola Crayons" It is the 96-crayon bonus box. It does say "nontoxic". Are there different kinds of Crayola crayons? Wax and non-wax?

here in the uk we have ordinary colour pencils and wax ones so would guess you do to!!

I used fabric crayons and they faded before a wash!! I got fabric markers and had much better luck.

Kyia

from the picture they are definitely wax ones and it sounds like you did everything right so am completely stumped now as to why it didn't work

Hm, that is weird. Maybe you didn't have enough of the color on the block to begin with. The way you described is exactly how I learned.

The fabric crayons work a little differently: You draw the design on paper and iron it onto the fabric. I tried that once and it came out really light as well.

Can you re-color? I would get a set of fabric markers (NOT Sharpie!) and color the designs. I have some that work like felt tips.