Blue light like that from smartphones linked to some cancers

al0ha writes: This study seems to say that exposure to LED light temp higher than 3000K suppresses melatonin because it contains increased blue light, and at least one city has gone to the expense of removing higher temp LED lights and replacing them with 3K lights. I'm confused — as a photographer I know sun light is ~ 5500K — 6500K depending on viewing standard.