First playing with dyes of the season!
I read about this technique on Ravelry (you can find anything on Rav) last year and have been itching to try it. Rav post on shaded dyeing. By rolling the yarn in a ball before dyeing, the idea is that the dye penetrates less to the inner layers, and you should be able to get a ball/skein shaded along the total of it's length. I used cochineal with alum mordant, and a silk/merino blend laceweight I bought at Knit-Knackers. The idea was to test the technique for use on my Guild challenge project later this year.
I was afraid the dye would penetrate too much, but it was just the opposite - after 1.5 hours in the pot, the center of the ball was still white when I reskeined it. So I dunked the whole thing back in the exhaust for a moment. This also helped even out the color a bit - the middle part of the ball was a bit tie-dyed in effect; with the ball looking rather patchy. It looks good (if you can tell by the very mediocre photo), but I think the next round I will try rolling the ball a bit looser.