The first thing you need to know is that in incandescent bulbs they don't turn on instantly. When I turn them on they are about a third or half bright and slowly increase to full brightness. My experience is about a minute and a half to full brightness, but this may vary slightly depending on room temperature. This result is based on 70 degrees. The mercury content in these lamps is listed as 1.6 and based on non-exhaustive research I have done, the usual range for mercury in CFL lamps is in the 3 or 4 mercury range. This probably means they are "greener" bulbs, but not necessarily that they last longer than other bulbs, as this usually depends on the quality of the ballast. The ones I had in my bedroom were good for accent lighting and backlighting when watching a movie, but not for anything that requires keen eyesight. These lamps are a big improvement. I use them in lamps in opposite corners of a 12" x 12" room (no dimmable curtains) and the crisp white light is not only better for eyesight but has a nice added mood-boosting effect. The 2700,000 bulbs I replaced gave off a yellowish glow and I had a lot of trouble adjusting the camera's color settings for indoor shots. My experience with 5000k is early but in my first experiment the color looks much closer to the real color. At first I thought that maybe after using them for a week or two they would "break in" and start to reach their full brightness sooner. . They still take the same amount of time, which isn't a problem for the way I use them, so I think it will depend on your needs.
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