I feel the acrea ink colors seem too light. Is there a problem?

"It may be that the ink is not sufficiently mixed. The acrea ink consists of pigments, water, and resin, among other components. If left unused for a while, these components may separate. To ensure proper mixing, shake the pen up and down with the cap on before use. If the ink still seems too light, residual resin on the nib from previous use may affect the color. Gently wipe the nib with a tissue, then make a test drawing to remove any excess residue before using the marker."