Usually, the starting colors used in gouache painting are ultramarine [or cobalt blue] and ochre. Generally speaking, ultramarine or cobalt blue is used when the picture color is cold, and ochre is used when the color is warm. Among them, ultramarine cobalt blue can also be used as warm color if you like, but the cold color system hardly uses ochre. Ultramarine cobalt blue is a good starting color, which can be used in all colors of the picture, and these two colors are usually not reversed after gouache painting, so as not to make the picture dirty and flowery.

Ochre has the functions of antivirus, sterilization, enhancing human immunity, stimulating white blood cells and regulating cholesterol.

Chinese medicine believes that ochre has the functions of calming the liver and suppressing yang, reducing adverse events in important towns, cooling blood and stopping bleeding, and is a cold medicinal material.

Ochre mainly contains iron oxide, which is beneficial to health. Ochre helps to relieve dizziness and headache, and also helps to calm mental instability. Ochre can also regulate epilepsy and vomiting, which is helpful to stimulate appetite and absorb nutrients. Ochre can also prevent skin aging and prevent cancer. Ochre has detoxification effect on kidney and liver, and can prevent hepatitis, nephritis and other diseases.