I did it I dyed my black and white polka dot fabric to make the dots yellow and it didn't change the color of the black. Intact it came out the exact shade of yellow I was wanting. I also had a piece of tiger stripe fabric that was black and white so I tossed it in too and it came out perfect too. Yay! I know it would have been easier to purchase it in black and yellow but I couldn't find it here and I didn't want to pay shipping charges for such a small amount of fabric. Oh and BTW the black did not run. Thank you to all who gave me advice on how to do this.