Cold task lighting -- very long, very unedited *LINK*
David Barnett - SW Florida
>New possibilities everyday, Wiley.
While some daylight fluorescent lamps aren't too bad, many still emit a surprising amount of UV -- enough to sunburn the back of your hand from prolonged exposure at close proximity (DAMHIKT). One advantage of the better brands is a correctly balanced color profile. Just centering on a particular color temperature isn't everything, and some bulbs are simply much better than others. Ott-lite, for example, has a superb color balance but costs more. This is particularly worthwhile to me as I need to accurately judge color in many tasks. However, if I'm doing tasks that are not color-critical, I still prefer these bulbs because I can see so much better and for longer without eyestrain.
When you first try an Ott-lite they may seem rather dim. It won't take long to realize that you can see exceptionally well at that illumination level, though. What you initially perceive as lower light intensity is really the absence of glare. In the older style of bulbs more brightness is needed to overcome the poor color balance to acheive sufficient contrast. So consider one the Ott-lites. Maybe try one if you haven't yet.
Another thing, it's often easier (and cheaper) to get the light where you want it in an anglepoise light fixture such as the ten dollar "architect's" clamp-ons available at nearly any discount office store. Ott-lite makes a 20-watt swirl compact with a regular screw-in bulb base. It's a little too heavy and long for some of these fixtures but it'll work well enough and they ARE cheap. Expect to pay just under thirty dollars for the Ott-lite True-color bulb, though. While I've tried many of the other so-called daylight or full-spectrum compact swirls, they don't even come close, but that's my opinion. Your mileage may vary.
Okay. On to cold illumination, specifically. There are two ways to go: 1) halogen-driven fiberoptics, or 2) white LED arrays.
The first method is simply a box with a bright lamp; usually a halogen, usually fan-cooled and passed through an IR-filter on its way to a fiberoptic light guide which pipes it where you want it. These boxes, called illuminators, are pretty much based on movie and slide projectors -- old technology, obviously. Of course, that doesn't mean that manufacturers didn't charge hundreds and sometimes thousands for these gizmos, esp. when the buyers had deep pockets (read government, medical, etc.). Lucky there's a glut of these things on eBay, where I bought three for less than fifty dollars each. Yeah, you'll see some go for way more $$$ and some for around twenty. No surprise there. One of mine, a brand and model I've seen sell very used for over three hundred, cost me about thirty dollars. The seller said the lamp didn't come on but the fan seemed to power up. I took a chance and after adding an MR16 socket for about two dollars I was up and running. That's another thing. Almost all these units use a readily-available EKE, EJE, or DDL projection bulb. Many of these illuminators need nothing more than a fuse or new bulb to get them up and running.
Okay. So you've got a light box. Now you need a light guide. There are all kinds, lengths, and styles but they all do the same thing; get the light from the box to where you need it. I particularly like goosenecks -- the kind that stay where you position them, but I use others, as well. Ringlights are pretty useful because I use low-power stereomicroscopes and also do some of my own product photography. Most useful for woodworkers are the dual goosenecks* and the long flexible pipe that you can fit to a magnivisor or pair of surgical telescopes. These are also great for sticking inside hollow turnings (you can see easily see through the thin walls**), and I've taped them to handtools and my foredom handpieces on occasion. They're excellent for surface examination of relief carvings, esp. lettering, and helpful for finishing and sharpening (esp. saws). The EKE light is intense (I rarely drive it over 80 percent, which also makes the bulb last much longer than the conservatively rated 200 - 500 hours) so you can really see what you're doing, even with 50 percent of power.
I should mention that some of these light guides have a focusable lens at the end (mine don't). If not, they can be easily added if you need a wider or narrower beam. Also, when you buy a used light guide, try to test them to make sure no-one has bent them tighter than the recommended bending radius. If enough fibers have been severed you'll get dead spots in your light pattern. I've not come across this in mine but it can happen.
On to 'white' LEDs. White LEDs are fairly new and are popping up everywhere from architectural lighting to Christmas tree strands. They're getting brighter, more efficient, and cheaper by leaps and bounds. I'm completely enamored with them and make luminaires; sconces, table lamps, soffit and cabinet lights, and so on. The now come in replacement lamp packages for most popular fixtures; floods, interior lamps, etc., and they cost practically nothing to run. The economies are staggering. One lamp I replaced cost nearly thirty dollars a year to run and burned out in about 300 hours. At seven bucks a pop per bulb, it adds up. The replacement, which will last about 100,000 hours before burning out, while not as bright, has a nicer color temperature (you can get these in warm white, daylight, super-daylight, blue (all 'white' LEDs are blue to begin with. Different coatings inside determine the color profile). You could even substitute an MR16 bulb in a fiberoptic illuminator but there's nothing as powerful in LEDs (that's afforable) as the 150-watt halogens... yet. These work quite nicely in canister, pot, and track light fixtures, though. Prices are dropping, though. You can get a miniature 14-LED task lamp that runs off 3-AA batteries for $7.95 from FDJ Online, a jewelry supply distributor. While this'd not be my recommendation, look for cheap and useful LED lamps to start showing up before Christmas '06. LED headlamps are lightweight, very bright, inexpensive and entirely useful, too. Yes, LEDs get hot, but with proper heat-sinking and product design the end user will never even notice.
So my recommendations? It'd be nice to have an Ott-lite AND a fiberoptic outfit, and you could realistically have both for 75 to 150 dollars. The intensity and versatility of the fiberoptics light guides are unbeatable, IMO. Keep your eye on LEDs, though. This is surely the future of illumination.
*Most of these goosenecks attach directly to the illuminator box, but you can find some that have a flexy section that runs from the box to the stays-put section that mounts to anything you want. These (I have both kinds) are much more useful for woodworkers. Also, connector sizes vary from manufacturer to manufacturer, so you may have to shim or make an adaptor, easy enough for us handy sorts.
**You can see through your hand, too, which is creepy, but it won't burn you, which seems weird at first.
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