In purchasing the necessary supply of colors, there is a choice between those that are in collapsible tubes, all ready prepared for instant use, and those that are still in powder form, usually put up in small vials, with a meta top screwed on.
Every form has it particular advantages to comend it, the origin cost being about equal ; the actual amount of color is more than double that in the tubes.
The colors in both tubes and vials are identically the same in name and in shade.
