I admire the work of artists who work spontaneously and successfully build on surprises but regrettably, I am not one of them. I am much more a planner/implementer/control freak. Here is how I document dye color formulas so I can get exactly the color I want.
With paint, mixing the color you want is straight forward: the color you have mixed will be the same when applied, allowing a bit of shade change for wet to dry. With dye, it is not so easy. The color you see when you mix the dye bath only has a general resemblance to the color you will get when the dye process is complete. When I have tried to adjust a color bath that seems wrong by adding more dye colors it has never turned out well! Unfortunately, What-You-See-Is-What-You-Get does not apply to dyes.
The only way to really have control of color is to test and keep accurate records. Obviously, a swatch does you no good if you don’t remember what you did to get it. For this, you need to measure accurately and keep notes. I use a gram scale that reads decimals to mix stock solutions with graduates and syringes to measure as accurately as I can, but use whatever works for you. Write down what you did immediately—it all goes vague and fuzzy really quickly.
Once you know what you mixed and have a swatch of the final result, it’s time to put it into a reference bank so you can always find that information in the future. After several false starts, here is how I now store my reference swatches.
I use blank cardstock that is perforated for making business cards, but anything stiff enough will work. I wrap a 2” x 3” swatch around the card and tape it down. The formula is written on the card. I include the strength and percentage of each stock color so I can easily adjust to different amounts of fabric.
The payoff for all this documentation is you always know how to get that fabulous burnt pumpkin or vibrant limeade color again. If you want a new color, reviewing the formulas used previously will give you a good start on how to adjust them to get the desired new color.