FD&C Red #40 Powder is a concentrated water based dye in dry powder form. Dilute in distilled water and then add to your water phase, drop by drop.
FNWL uses the standardized name for this color additive. Standardized names, however, can sometimes be vague. In our experience, Red #40 is a bright shade of red with a slight yellow tone. The amount of colorant that you use will affect the intensity and vibrancy of the hue.