Propylene pigment is insoluble in water, but it softens and expands slightly when it meets water. Once expanded, it will peel off naturally, so it can be washed off with water.
Gouache painting is very effective in running newspapers, with bright colors and eye-catching. Suitable for propaganda slogans and titles, which are better than chalk. If it is on the outdoor blackboard, it is recommended to use gouache paint, which lasts longer than chalk.
The poster color is made of water. Drawing on the blackboard is both convenient and beautiful. You can also wipe off the wrong place with a wet cloth. Even if the color has dried for a long time, you can clean it with more water and cloth. This kind of advertising color is used in proofreading and black newspaper, and it is also very convenient to modify.
Extended data:
According to the content of the blackboard newspaper, determine the overall tendency of color effect, whether it is full of vitality, solemn and quiet, warm and cheerful, subtle and deep, magnificent or simple and elegant. If the Spring Festival is celebrated, the colors should tend to be warm and cheerful, reflecting that the life of soldiers should tend to be full of vitality and depict a healthy and uplifting atmosphere.
Attention should be paid to the overall effect of color, both harmony and contrast, so as to produce a good overall color effect and make the power of feeling beauty achieve unity, harmony and contrast. This is the principle of correctly handling the dialectical relationship between opposites and unity of colors.
Reference source: Baidu Encyclopedia-Blackboard