Originally Posted by AU_Prospector
b) I have had bulbs coming from the same multipack emit different types of light (ie some yellow/warm light and some blue/cool light right from the same pack. I have had to switch bulbs to try and even out light from multilight fixtures so it doesnt look goofy.
d) Most bulbs emit a cold harsh blue light. In some of my multi bulb fixtures I mix in normal incandecents to soften this effect.
Which leads me to my question. . . CFL's still generate a lot of heat, how on earth can a 23W CFL only use 23 Watts when it generates a significant amount of light, plus some heat? Many are too hot to handle when they are on...
People should be aware that CFL bulbs can be purchased in four different light spectrums, or light "colours"; Soft White, Bright White, Cool White and Daylight. As you go from Soft White to Daylight, the spectrum of the light produced by the bulb contains less and less red light and more and more blue light. It could be that you bought a package of CFL bulbs that someone else had returned, and since the bulbs don't indicate what kind of light they produce, you got an assortment of different kinds of CFL bulbs in the package. That's the only way you could get different results from bulbs from the same package, or why you're saying that most bulbs emit a "harsh blue light". You just need to pay attention to what KIND of CFL's you're buying.
"Soft White" CFL bulbs produce light that's most similar to an incandescent light bulb, and it's what most people prefer. If you look for the words "Soft White" or "Bright White" on a package of CFL's, I think you'll be happy with the purchase.
"Daylight" CFL bulbs are the ones that produce the "cold harsh blue light" that resembles the light from an arc welder. These bulbs produce light that has a uniform intensity of all the different frequencies of visible light, so it's the "whitest" light available from a CFL. If you take pictures indoors with a digital camera, these bulbs won't cause all your pictures to be brown the way incandescent bulbs will (if you don't use a flash).
The reason a 23 watt CFL can produce the same light output as a 100 watt incandescent bulb is because the incandescent bulb works by generating a lot of heat, all of which is wasted. MOST of the energy consumed by a 100 watt incandescent bulb is converted into heat, and the light it produces is a byproduct of that heat. With CFL's, MOST of the energy consumed is converted into light, and only a bit of the energy is converted into heat.
The way all fluorescent lights work is that an electric current flows through mercury vapour, and when an electron hits a mercury atom, it produces a ray of ultraviolet light. The phosphors on the inside of the fluorescent tube or CFL spiral then convert that ray of UV light into a ray of visible light. So, you can change the kind of light a CFL or fluorescent tube produces by playing with the kinds of phosphors you coat the inside of the tube with.
It's that mercury they put in CFL's that's causing concern over potential mercury pollution because with every CFL bulb someone tosses into their garbage can, there's more mercury in the soil at landfill sites. That mercury can eventually pollute the soil and ground water in the area. Here in Canada the chain of Rona hardware stores have special CFL disposal bins where you can dispose of CFL bulbs and know that the mercury in them will be recycled.