05-26-2011, 12:52 AM
I completed some tests today on color temperature of fluorescent lamps. As a bit of background, my workbench area is currently lit with two fixtures that both have lamps with a color temperature of 5000 Kelvin (this is also referred to as "sunlight"). I purchased two pair of 3500 Kelvin lamps to try them on for size, based on Gerry Cornwell's excellent commentary on the Model Rail Radio Podcast (#25).
The images in the gallery are of my workbench area with 5000 Kelvin lamps, 3500 Kelvin and a mix (one of each in each fixture). To control the images, I took paired photos using the "Sunny" and "Fluorescent" white balance settings - not auto. This will allow you to see the relative differences in color, though none of the photos are the actual color I'm seeing in real life (one is close). Details of the specifics of the lamps used are in the photo captions.
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A note about lamps in spite of what the Big Box Store guy told me, within a color temperature not all lamps are created equal. For example, GE makes two similar T8 lamps: F32T8 SP35 ECO and F32T8 SPX35 ECO. Both are T8, both are 3500 Kelvin color temperature, but the SP35 has a CRI (color rendering index) of 78 and 2800 Initial Lumens while the SPX35 has a CRI of 86 and 2950 Lumens. The "X" is also about 75% more expensive (~4.50 vs. ~2.60).
Big Box stores will generally have the cheaper lamps.
GE also sells lamps optimized for other uses (long life, high efficiency, quicker start) that didn't apply to me, but did serve to make this topic more complex than I'd expected. I would suspect that other brands have similar ranges, but I didn't investigate.
As expected, the 3500 Kelvin lamps are quite a bit redder (or depending on your perspective, the 5000's are quite a bit bluer). From a CRI perspective, both lamps I'm experimenting with are equal and the 3.5K lamps are a bit brighter - though I can't see it - so it will come down to what looks good. If you change a lamp color - make sure you leave it in for a few days. Your brain will correct to the new "normal" - white will again seem like white.
My reason for trying the 3500s was partly out of curiosity and partly to amplify the reds, of which there were plenty in the era I'm modeling (1930's) - just about every boxcar had some red in it! As a side benefit, it may help my father, who has a degree of red / green color blindness, by boosting the reds he can see.
The images in the gallery are of my workbench area with 5000 Kelvin lamps, 3500 Kelvin and a mix (one of each in each fixture). To control the images, I took paired photos using the "Sunny" and "Fluorescent" white balance settings - not auto. This will allow you to see the relative differences in color, though none of the photos are the actual color I'm seeing in real life (one is close). Details of the specifics of the lamps used are in the photo captions.
<!-- m --><a class="postlink" href="http://goodman312.zenfolio.com/p602649692">http://goodman312.zenfolio.com/p602649692</a><!-- m -->
A note about lamps in spite of what the Big Box Store guy told me, within a color temperature not all lamps are created equal. For example, GE makes two similar T8 lamps: F32T8 SP35 ECO and F32T8 SPX35 ECO. Both are T8, both are 3500 Kelvin color temperature, but the SP35 has a CRI (color rendering index) of 78 and 2800 Initial Lumens while the SPX35 has a CRI of 86 and 2950 Lumens. The "X" is also about 75% more expensive (~4.50 vs. ~2.60).
Big Box stores will generally have the cheaper lamps.
GE also sells lamps optimized for other uses (long life, high efficiency, quicker start) that didn't apply to me, but did serve to make this topic more complex than I'd expected. I would suspect that other brands have similar ranges, but I didn't investigate.
As expected, the 3500 Kelvin lamps are quite a bit redder (or depending on your perspective, the 5000's are quite a bit bluer). From a CRI perspective, both lamps I'm experimenting with are equal and the 3.5K lamps are a bit brighter - though I can't see it - so it will come down to what looks good. If you change a lamp color - make sure you leave it in for a few days. Your brain will correct to the new "normal" - white will again seem like white.
My reason for trying the 3500s was partly out of curiosity and partly to amplify the reds, of which there were plenty in the era I'm modeling (1930's) - just about every boxcar had some red in it! As a side benefit, it may help my father, who has a degree of red / green color blindness, by boosting the reds he can see.
Matt Goodman
Columbus, Ohio
Columbus, Ohio