Mordant such as metal salts and dyes from the plants including madder and gromwell are used to fix the colors in the textiles. With different mordants, the colors obtained are different. For example, a variety of colors can be acquired from the salizarin (C₁₄H₈O₄) in the madder when different amount of metal salts are used. The pH value of the mordant plays a vital role in affecting the colors. With pink salt as mordants and keeping the pH value of mordanting bath as 5, after bathing for 30 minutes, then add a little amount of bicarbonate solution and wash it several times, the color obtained is orange red. While using chromium salt as mordant and keeping the pH value as 5.5 with Potassium Dichromate (a kind of chromium salt) and acetic acid, dark khaki can be collected with the previous approach. The colors obtained can be varied with only little difference in pH value, proving that the pH value is crucial in mordant dyeing.

In our video, gromwell and vinegar were used as the dye and mordant respectively. As vinegar is acidic, the colors obtained from solutions with different concentration of it are tested in our video.

Safflower is used as the direct dye in the demonstrating video. Two color pigments, which are yellow and red in the safflower are found within this plant. The process of removing the yellow pigments is required. The yellow pigment is dissolved in acidic solution while the red pigment is dissolved in alkaline solution. To dye the cloth with the red pigment only, the pieces of the flower has to be washed with acidic solution first. After drying them, put them into alkaline solution in order to extract the red color. Playing an important role in affecting the pigments in safflower, the pH value is critical in determining the colors collected eventually. Thus, the effect of different pH value of the direct dyeing solution on the colors is also examined.