Originally Posted by AveCosplay
I've never heard of using hair dye on fabrics but I highly doubt it would work. If you need to dye fabric I'd recommend just buying Rit Dye, it's not expensive and I've seen at just about every craft store I've been to. Also be careful when dying fabric, it can get messy!!! You should probably go buy a large pot just for dying fabric while you're out there!!!
I agree with AveCosplay
here. You use Rit Dye or any fabric dye for that matter. That's the whole purpose for Rit Dye. Hair dye is meant for...... well, hair. If The fabric that you want to dye is a plain white color that's cotton, rayon, ramie, linens, or blends, you're fine, just look for the color you want. Just add salt to the dyebath. If your pants is a white color that's nylon, silk, or wool, then add vinegar to the dyebath.
What are you trying to achieve exactly? Sometimes the light colors will actually turn into the desired color, but not always. It will sometimes turn a light color into another color. Here's 1 example for each situation:
1. When I was doing my Gunner Yuna cosplay, I needed to dye my half skirt into a darker blue at the top. I had to decide which darker blue I wanted and would work best. I chose Royal Blue. The fabric itself was almost a baby blue color and it happened to be cotton. To make sure that it was what I wanted and needed, I did a swatch test to see how it turned out. To my surprise, it turned perfect. Here's the end result: http://www.cosplay.com/photo/3485721/
2. If you needed a red color t-shirt, a place like WalMart was totally out of plain white and red t-shirts and you're stuck with a yellow, once you try to dye the yellow shirt into a red, you might have an orange shirt afterwards.
So overall, it's always best to dye a plain white color piece of clothing to the desired color that you need and use proper dye. Since your dyeing a piece of clothing, you use fabric dye.
Does that make sense?