Artificial lighting

[Joan Breckwoldt]

I just checked that website, say's that bulb is rated at 5500 Kelvin. Hmm, I think mine might be higher.

Okay, here's a question. Does all flourescent light put out the same temperature light? It seems like it would.

Joan

[Michael Georges]

Originally Posted by Joan Breckwoldt

I just checked that website, say's that bulb is rated at 5500 Kelvin. Hmm, I think mine might be higher.

Okay, here's a question. Does all flourescent light put out the same temperature light? It seems like it would.

Joan

I don't believe so. Your standard commercial flourescent bulb is between 3000 and 4000 K with a CRI somewhere between 50 and 80. They are much more yellow-shifted.

[Joan Breckwoldt]

Well Michael, that explains a lot, if what I got from Home Depot falls under 'standard commercial bulb'. But, how can it be that one flourescent bulb puts out 5500K and another 3000K? I don't understand that.

Joan

[Joan Breckwoldt]

I found a website that gave me some information on flourescent lamps. I have copied some of the info below:

Fluorescent Phosphors The color of fluorescent lamps is created by mineral phosphors in powder form which coat the inside of the lamp tube. The chemical make-up of these phosphors determines the lamps CRI, its Color Temperature, and how much light the lamp produces. There are four types of phosphor coatings:

Traditional halophosphors Are inexpensive coatings which usually provide the entire spectrum of light. But, there is a trade-off between Color Rendering and Lumen output. Poor color rendering lamps such as "warm white" and "cool white" have high Lumen output. Good color rendering lamps such as "warm white deluxe" and "cool white deluxe" have low Lumen output.

Prime color or Tri-phosphors Are very expensive coatings with good color rendering and high lumen output. Lamps of this type are produced under the trademark, Ultralume.

Double-coat lamps Have a coat of halo-phosphor and a coat of tri-phosphor. Double-coat lamps which have a thick tri-phosphor coat are fairly expensive but have very good color rendering properties. They are known by the trademarks SPX, Designer 800 series, etc.. Double-coat lamps with a thin tri-phosphor coat are much less expensive, but still have full light output and reasonably good color rendering. These lamps are known by the trademarks SP, SPEC, Designer, and others.

Rare Earth Phosphors Have a thin and thick coat of rare earth phosphors and are just becoming available. The CRI for these lamps will be 70, 80, and 90 and in a variety of Color Temperatures.

Whew, that's more than I wanted to know but at least it convinces me that all "flourescent" lamps are not equal.

The bulb I'm using doesn't have any info about it's temperature and their website had a range, just like you said Michael. So, I guess the best way is experimentation and maybe try that Verilux bulb.

Joan

P.S. This is where I found the above info:http://www.lightcalc.com/glossary.html

[Joan Breckwoldt]

The Commercial Electric (that's the brand name) website says this about it's screw-in bulbs: "This fluorescent 42 watt has one of the highest light outputs available. It comes in two colors, 2700k and 5100k full spectrum daylight. They screw in to almost any socket and put out the same amount of light as a 150 watt light bulb." But, unbelievably, there is no info on the package of my bulb indicating which bulb I have. My package says "warm white light" and that it's equivalent to 75 Watts light output. This light was meant to go in a table light to help someone read better so I guess this info isn't important to the general public. Time to buy a bulb that I know something about so at least I can begin to understand why a photo I take is too warm, cool, etc.

Joan

[Dan Landrie]

Hi I'm an electrician, ballast are actually rated by how much noise they make the rating method is alphabetical with a sound rating of "A"being the quietest it will say on the ballast label what the sound rating is.

[ReNae Stueve]

You will find if you really learn as much as you can about the fluorescent world that there is a catch 22 here. Be an informed consumer.

Self ballasted compacts or CFL lamps that you screw into your table lamps are typically designed for residential use and as such are an FCC class B EMI ballast EMI protects againt electromagnetic and radio frequesncy interference. (so you don't have to wear tin foil on your head. ) they are electronic an as such do not have a noise factor that the old electromagnetics had. Temp is usually 27K although almost never rated. CRI is not a goal or constant through the life of the lamp. These lamps are designed to save energy not provide critical task light.

This is the case with all fluorescent lighting systems. I use the word "systems" because the product is always a ballast and lamp working together to produce a desired effect. And that goal is by design, long life and lower watts per lumen. CRI and other ratings are used only to compare them to their like product family members.

Even though many aftermarket labelers are promoting home CFL's as some kind of magic light, these claims are not in any way true. Please be informed as a consumer, What you pay $100.00 plus for is sold by Graybar and GE for $5.85, and all are made by 4 companies in the US and China and are relabeled for residential and home depot sales. ata very high profit