There are a few of factors which influence the final shade: (1) ratio of dye:water (2) ratio dye:wool (3) time allowed for dye to set in wool. (1) If you have a very diluted solution, the final outcome will be lighter than if you have a concentrated solution; (2) If you put in a lot of wool relative to the amount of solution this will also play into having a lighter outcome; (3) Even if you have high dye concentration and a little bit of wool relative to the amount of solution, if you don’t let the wool sit in the dye solution for long enough, it will come out lighter than if you let it sit.