Paula/mods, please move and rename this topic as necessary.
This is from my own experience and the directions on the package, which I found complicated even when translated.
Simplicol brand is the easiest dye to find, however there are two different kinds and some caveats you should be aware of:
First, read these valuable instructions:
I didn't. And didn't know the difference between an all-purpose dye, and a fiber reactive dye. The Simplicol dyes appear to be available in both formulations.
The dyes are widely available at DM, a common drugstore. They cost about 6EUR a box and will dye 600 grams (dry weight) of fabric. A lot of sewing shops and fabric supplies, do not have dyes.
There are two kinds of Simplicol dyes at DM as of this writing: One is the old style all-powder. As far as can be identified, this is not a fiber reactive dye, and requires hot water to work the best, although I could be wrong about the exact method. Only posting this part so there is no confusion as to which dye box to get, and which directions these apply to. I have see directions translated from deutsch for the simplicol dyes, however they are sometimes for the older style, and the two dyes work differently and the dying methods are different.
For the reactive dye, select from the brightly-coloured 'Real colour' box (Echtfarbe). NOT the more plain box. The old-style is a single large bag of powder inside. The newer, highly-coloured box has a liquid container on the top half, and a powdered waterglass salt on the bottom.
Using the suggestions on the PBURCH site, find out how long it takes for the washing machine before the machine pumps the water out, with 'Wasserstand' (increased water level) selected.
If the clothes can be washed in 40 degrees, choose the Pflegeleicht cycle, 40 degrees. If they cannot tolerate temps that high, use 30.
600 grams: Only if you are using only one box of Simplicol: With the clothes in the machine, press Start. Add the included salt (waterglass) immediately, and add 500 grams more regular non-iodized salt (plain salt, the cheapest is dishwasher salt).
Then add the dye portion to a 1 liter container of water, but do not add this to the detergent inlet yet:
BEFORE adding the dye, wait five minutes from pressing the Start button and adding the salts.
Now, add the one liter of dye water.
Let the cycle run through. Paula suggests stopping the washing machine before it pumps the water out, and resetting it (there should be a 'reset' option to have it forget the program), then starting the Plegeleight program over again to run longer. This gives the dye more time to react with the clothes. There may be a Wasserstand button or option on the washing machine, use it. This increases the water level and helps the distribution of the dye.
More than 600 grams/ more than one box: Same as, but no extra salt. Only the salt included with the kit.
That's it! You might want to wash the item once by itself to make sure all the extra dye is out. It should not bleed though - unlike older-style 'all purpose' dyes.
I posted similar instructions on another forum, although abbreviated here as most will be aware of the basics already. I had good results, but could see how another package of reactive dye would have helped with the black dyeing I was doing.
Thanks to paula!