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JOEL Joel's Blog

Full Spectrum Fluorescent Lighting

06/16/2009 Cheers up the entire workspace

Full Spectrum Fluorescent  Lighting 4When we moved into our space over a year and a half ago one big expenditure was for lighting. Our space is lit by oodles of 8 foot fluorescents and a huge bay of windows on one side. Most of the time we just use natural window light - A photographer from Fine Woodworking once remarked that my shop had more natural light than any other workshop he had been in. Most of our assembly and saw filing stations are by the window which give great light, but at the time I was concerned about the light around my bench.

The primary use for my workbench is testing, prototyping, and most of all photographing stuff for our catalog, this blog, and other pictures. So I was worried about the purple tint you get from mixed lighting. With a modern camera you can easily adjust white balance for daylight or fluorescent but not both at the same time. So I was worried that the part of my pictures near the window would look okay but the part in the background, that gets some light from the overhead lighting would have a purple fluorescent cast.

So a photographer I knew recommended full spectrum fluorescent bulbs which instead of having a purple cast are tinted to be more blue and mimic the natural color temperature of daylight. Click here for an explanation of color temperature .

I did some research and the folks that sell full spectrum bulbs basically say that it makes your showroom more appealing, makes people more cheerful, good for morale, basically everything except world peace and that's coming soon.

So the bit about showrooms seemed a good idea, and it would solve my photography problem - so we bit the bullet and forked over a lot of cash to change our 8' bulbs to full spectrum. Just the bulbs not the fixtures. The results were great!!!! I can tell you a year and a half later that I would do it again in a heartbeat and I even bought a full spectrum reading light for my dad because, because for those with vision problems, they are easier to read by.

We don't sell the bulbs. This isn't a sales pitch. We are just satisfied customers. We got our bulbs from here: Full Spectrum Solutions, but I think there are lots of vendors around. If you are lighting your workshop I highly recommend them, if for no other reason that the wood will look wood color, not greenish, but mainly because it makes a nicer environment to work in.

Join the conversation
Joel,
I put daylight T8s (6500K) in my shop a few weeks ago and noticed a huge difference in the amount of light compared to the old 120 watts of incandescent lighting I used to have. I'm not sure I like the blue cast but it's definitely bright. I do still use a directional incandescent raking light though when I need a raking light.
06/22/2009 Chris Friesen
Bob, I too find the 6500K bulbs too bluish. I use 5000K bulbs with a CRI of 86. Not quite as good colour rendition as the ones at the URL listed, but I could source them locally.

Joel...if you ever need even better colour rendition, the Philips TL950 bulb has a CRI of 98 at 5000K. Apparently this is available at Home Depot in the USA. (But not in Canada unfortunately.)
06/22/2009 Joan Touzet http://www.atypical.net/
Beware of too many false claims about these bulbs. Most (if not all) commercially available coatings on fluorescent and CFL bulbs simply filter the light from the original source -- meaning you are limited to the emission spectra that come from the fluorescent process. There is insufficient variation in the coatings from various bulb manufacturers to make too much of a difference.

Check out this URL: http://www.nofs.navy.mil/about_NOFS/staff/cbl/lumentab.html for more information, including a visual representation of emission spectra for each bulb type.

In short, unless a manufacturer is willing to publish a table of emission spectra across the visible wavelength (extending partially into the IR and UV spectra) anything else is hucksterism - including the CRI, and yes, the colour temperature. Ideally this should be compared with the emission spectrum of the Sun itself, depicted here in black: http://www-molycell.cea.fr/home/liblocal/images/graph_molycell.jpg

As you can see, good ol' incandescent or halogen still provides one of the best spectra for emulating natural daylight, though obviously skewed towards the red end, and missing some of the shorter blue and UV wavelengths. The old Luxo "natural lights" that combined fluorescent and incandescent still provide, to my eye, the best artificial colour rendering short of some very expensive theatrical/film lighting systems.

Ultimately, we also use the Philips T8 5000K bulbs with the CRI of 86 in our workshop. These are good "enough" without paying a ton in speciality pricing for not much gain / dimmer overall output / snake oil. Where necessary we have incandescents in gooseneck clip lights for spot work and xenon flashes for photography.
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