The 108 colors in the HK HOLBEIN collection use fine pigments to create high-quality results. Each color is formulated to give a consistent hue that is brilliant and permanent. The chemists from Holbein use a high level of quality control to achieve a precision that is consistent throughout different production runs. This allows you to choose the same color months or even years apart and still end up with the exact same hue for your work. You always know just what you're getting when you choose these watercolors, and you always get a color that will give you exciting results that pop. The innovative techniques used to create these colors are modeled after the hand-grinding of pigments that artists did during the Renaissance in order to create brilliant colors that have the right characteristics for truer color and an easy consistency. Tube sizes of both 5mL and 15mL are available in all 108 colors.Watercolors from HK HOLBEIN are specially formulated to create consistent color that will allow you to create your artistic vision.