Once, I was a fastidious dyer. Then, I realized I wasn't in the business of creating reproducible shades, which freed me up immensely. Now, when I do a dye run, I put three or four mason jars in the canner, fill them half full with water and add a teaspoon of citric acid or a sploosh of vinegar. No salt. Then I mix my dyes from washfast acid dye powder, just going by eye and experience. The dye is added to the jars - here I had one jar lavender, one moss green, one blue, and then a fourth colour - forest green in the water surrounding the jars in the canner. I put the pot on to simmer, and stuff squares of pre-wet cloth into the jars. The take up happens quite fast, and if it looks like it will be darker than I hoped, I add more fabric to absorb the excess. I move the cloth around in the jars a bit, but it doesn't matter if the colour is uneven because it won't show up in the hooking, or if it does, will just add a nice variation of tone.
So the whole pot just simmers for about 45 minutes - I wait until the dyebaths clear, then give it another 15-20 minutes to make sure it's fixed. Then cool, rinse, throw in the dryer - more felting is good for hooking fabrics and I'm ready to go.
I was especially pleased by the darker mossy green near the bottom of the picture - it was an uninspiring dusty mouse colour before, now it's perfect for salal leaves.