Especially Reseda (dyers weld) likes hard water for a shining color, also with madder root one can change by the water hardness the color lightly.
Here it helps, to add chalk to make the water hard.
As a tip: We always take on 200 ls of water 2 kgs of chalk.
Also known as Limestone; calcite; aragonite; chalk; marble; pearl; oyster.
Not suitable for consumption.