Opaque white is useful for hiding errors… But did you know it can also be used to draw "in the negative" on a screen? By projecting white, you can, for example, draw stars in a dark sky, foam on the sea, or the impacts of an explosion…
You can use white correction fluid (or opaque white) to add highlights to your drawing. You can also use white calligraphy ink: because it is easier to use, it is ideal for beginners!