Phthalocyanine is a natively stable dye (has no need for stabilizers) and CD-Rs based on this are often given a rated lifetime of hundreds of years. Unlike cyanine, phthalocyanine is less resistant to UV rays and CD-Rs based on this dye show signs of degradation only after two weeks of direct sunlight exposure.[clarification needed][citation needed] However, phthalocyanine is more sensitive than cyanine to writing laser power calibration, meaning that the power level used by the writing laser has to be more accurately adjusted for the disc in order to get a good recording; this may erode the benefits of dye stability, as marginally written discs (with higher correctable error rates) will lose data (i.e. have uncorrectable errors) after less dye degradation than well written discs (with lower correctable error rates). Azo dye CD-Rs are dark blue in color, and their formulation is patented by Mitsubishi Chemical Corporation.