Fluorescents are a bad way to light a woodshop

[Jamie Buxton]

I’ve recently been teaching in a shop which is lighted with fluorescents, and it reminds that they’re a terrible way to light a woodshop. They have two bad characteristics:


1) Bad color

I love wood. Among other things, I love it for its color. Almost all the standard cabinet woods turn weird ugly colors under fluorescents. That rich red cherry turns ugly brown, maple turns kinda green, walnut just goes flat, and the list goes on. It is just lots less fun to work with wood under that light.

In addition, any part of the job which requires color sensitivity --- for instance deciding which planks to use near each other --– is difficult to do under fluorescents. And don’t even think about stains or dyes; they often look way different under fluorescents.

(And oh by the way, the color rendering index which fluorescent manufacturers push is hogwash. While it is true that a lamp with a CRI of 92 is better than one with a CRI of 60, it is still bad. For a while, I had a shop lighted with the highest CRI lamps I could buy, but they were still a very different color from sunlight.)



2) Diffuse light

The large size of fluorescents naturally produces diffuse, even, lighting. That’s a bad thing in many woodshop operations. A point source like an incandescent is much better. Here’s some examples of where a point source is good:

• Edge-gluing planks. With a point source at a nice flat angle, misalignment of the planks is easily seen by the shadow at the edge of the plank. Triming solid edgebanding is similar.
• Jointing. You want to make passes on a jointer until the jointer hits everyplace along the edge. This is easy to see if you hold the plank up so that the light glances along it, and unreliable under fluorescent.
• Sanding. With a point source at a low angle, it is very easy to see sanding scratches. Under a diffuse light they often escape –-- until the furniture goes into a home someplace where sunlight or a lamp exposes the mistake.

Another bad effect from diffuse lighting is that chatoyance is greatly diminished. Chatoyance really wants a light which is a point source, so that the reflection changes when you move your eye. With a diffuse light source, there’s no change when you move your eye. The result is all that beautiful curl disappears under fluorescents, and again some of the pleasure goes out of woodworking.

The better way to light a shop is halogen floods. They provide better color and chatoyance, and help you do better work.

[Jamie Buxton]

Utilities strongly push fluorescents because “they are much more efficient” --– that is, they’ll cost you less to light your shop. Let’s run the numbers on two cases…

1) A two-car garage lit with 12 65-watt halogen floods. That’s a lot of light. The light is consuming 780 watts of electricity. The average cost of electricity in the US is about 8 cents per kilowatt hour. That is, this lighting costs 6 cents per hour of operation.
2) The same two-car garage lit with the same amount of light from fluorescents which have a high color rendition index (90 or better). High-CRI fluorescents are about three times as efficient as halogens, so this lighting would cost about 2 cents per hour of operation. Put a different way, the halogens cost 4 cents more per hour of operation.

Let’s say the shop lights are on 500 hours in a year. The annual extra cost for the halogens is $20. That’s darn puny in return for a big improvement in darn near everything we do in a shop.

[Dan Forman]

Jamie---I agree that high CRI readings are deceptive, the higher numbers give a distinctively cold (blue cast) light. That's why I've been cautioning those who are talking about T-8 lighting. But you can get pretty close with a combination of T-12 "warm"(yellow cast) and "cool" bulbs, one of each per fixture. They really balance each other out, filling in the deficiencies of each individual bulb. I'm an artist, and that combination is the best I've found to date as far as color accuracy goes.

I also agree with you that it is good to have at least some point source lighting too for the sort of tasks you mentioned. But often times for other activities that can be distracting as well, especially if one has low ceilings such as in a basement. It can lead to unwanted glare.

Halogens give off much more heat than flourescents, which can be a blessing or a curse, depending on the season and shop location. Interesting figures on the cost element, the extra energy must be converted to heat, but it doesn't seem to put much of a dent in the wallet.

Probably the best solution would be a combination of sources to suit the task at hand. I have been very happy since adding five flourescent fixtures to my basement shop, each equipped with one warm and one cool high output T12 bulbs. I have a couple of incandescent ceiling fixtures which were there to begin with, as well as a portable clip-on lamp for when a point source is needed. I may try adding a halogen flood or two just to see what will happen, but the combo of warm and cool bulbs works well for most things, and is much easier on the eyes than standard flourescent lighting.

Just offering this as something for people to think about, not trying to convert you!

Dan

[Jeff Sudmeier]

Wow I never knew I wasn't having fun in the shop!!

That said, I use florecents, incandesents and a hallogen lamp. I set up the hallogen lamp when I am sanding or other fine work. For the rest, the florecents work just fine.

[lloyd morris]

Jamie,Thanks for the information regarding fluorescent lighting. My wife is a physician who sees and treats a lot of people who experience the negative physical effects of fluorescent lighting in the workplace. By far the most common problems she sees with fluorescent lighting is eye strain and migraine headaches. The problem is much more common is in environments where the only light source is fluorescent lighting as opposed to several light sources including natural light.While I have not had any physical problems from fluorescent lights in my small shop, I switched over to a combination of incandesents and a halogen lamps last year and noticed a big difference all the areas you mentioned. Thanks,Lloyd Morris

[Larry Browning]

I have nothing but T8s in my shop. I never knew that I was unhappy with them. As far as I was aware they worked great. I guess I just don't know any better. All I know is that I used to have 2 8ft T12 fixtures in my 2 car garage "workshop" which produced terrible lighting. When I built my new 30X30 workshop i installed 12 8ft T8 fixtures. And up untill I read this post I had perfect lighting. There are no shadows no matter where I am in the room and they don't hum at all. The don't produce much heat, which for the most part here in Arkansas is a good thing. And the best part is I can actually SEE what I am doing. My projects seem to come out of my shop looking the same color as they were in my shop.
This post makes me think that sometimes I might be better off not knowing negative things about stuff I thought was as good as it could get.

[lloyd morris]

Larry,I think you raise a good point. You probably do have perfect lighting for you and your shop. Everyone's eyes are different and many, possibly even most people get a very good result with fluorescent lighting. I did not have T8s in my shop and am glad to hear the work well for you.Lloyd Morris

[Tim Sproul]

Let’s say the shop lights are on 500 hours in a year. The annual extra cost for the halogens is $20. That’s darn puny in return for a big improvement in darn near everything we do in a shop.

Conservation is more than just what you, as an individual, save. If every customer of the electric grid didn't give a hoot about $20 savings here and there......we'd not have an electrical grid anymore. Heck....think about how bad the oil situation would be if we all drove vehicles that only got 10 mpg because going to 30 mpg would only save us a few hundred a year......


I agree that fluorescent lighting isn't ideal for everything. I disagree that it is unworkable. Fluorescent lighting works well for ambient lighting and should be supplemented with task lighting as needed. Those $20, 500 watt halogen work lights are great for finishing. Get the $40 version and they come with a stand......I'd also wager that fluorescent lighting is the preferred alternative for hobbyists because you can easily surface mount fluorescents. It is a much more involved task to install can lighting in an existing structure - especially if you don't have attic access.

[Larry Browning]

Sometimes this forum is very frustrating to me. It seems that no matter how much research I do and how hard I try to do things the proper way and to make good decisions on how to spend my time and money, there is something I didn't consider or some better "thing" I should have bought instead of the one I did. Sometimes I think that maybe I'm just better off not knowing I screwed up. The saying "ingorance is bliss" is really true.
But, even with that said, The information here is truly outstanding and the quality of the projects I turn out is much better because of this forum.

Larry

[Dick Heifner]

Hello all,
What is the difference between t-12 and t-8 fluorescent lighting ? I seem to be in the dark about half of the time in my shop and have 2- 8 ft, t-12 fluorescent lighting fixtures.
Thanks ,
Dick

[John Bush]

Hi All,
We use "color corrected" fluorescent bulbs that seem to eliminate the green and blue cast found in conventional fluorescents. We are able to match natural colors well and the illumination is good. I think the bulbs are classified as 5500K and are manufacured by Durotest. Kind of spendy compared to the conventionals but appropriate for us. Good luck, John.

[Tom Hintz]

When I first built my current shop (converted the garage when the wife was away) I began by lining the ceiling with flourescent fixtures. Two years later, after fighting with them non-stop, changing builbs, ballasts and the occasioanly fixture I outright assasinated, I ripped them all down and tossed em. Now I have incandescent lighting throughout, I can see better than ever and if it is costing me .04 or .05-cents per hour more, so be it. I can die poor but happy.

[Joe Pelonio]

Another disadvantage to flourescents is that they have the additional maintenance cost/time for the ballasts and starters. My inside shop and showroom are 4 bulb 4' fixtures (suspended ceiling) and out in the warehouse/woodworking part is dual bulb 8' flourescent that
are 16' up. Not easy when you can't tell which bulb is bad or if it's the starter or the balast. I use halogen floods on a stand for supplemental
light as needed and when dealing with a customer on color often step outside into the natural light. For a computer area the Ikea hanging
halogens are great.

[Kevin Post]

I have a combination of fluorescent and incandescent lights in my shop. I'd rather have windows but...

One thing that hasn't been mentioned is how cool it is when the tablesaw blade grabs a hold of a tiny, offcut piece of wood and fires it at the ceiling where the 8 ft fluorescent fixtures live - *PINGGGG* - *CRASH*.

DAMHIKT

[Roger Myers]

I always try to stay out of these lighting threads...but....

Some basics... (maybe more than you want to know, but not as much as you need to know)

Bulb sizes/shapes are generally designated with a letter and a number - in the case of linear fluorescent lamps, this is a T (for tubular) plus a number which designates the size in 1/8's of an inch. Hence, T-12 is a tubular bulb that is 12/8's of an inch in diameter and a T-8 is the same shape but only 8/8's of an inch (or 1") in diameter {you thought lumber yards were the only ones to mess with things like 5/4 }. There are also newer (becoming very popular in industrial and commercial applications) T-5 bulbs (yes, 5/8" in diameter) and there are also special purpose T-2 fluorescent lamps (display cases, etc). By contrast, the traditional automotive tail lamp bulb is referred to as a S-8 lamp (spherical shape, 1" in diameter). Length of fluorescent lamps in the US is generally 4' or 8', but there are other sizes as well.

Ballasts - T-12 utilize magnetic ballasts. T-8's and T-5's use electronic ballasts (there are exceptions, but not for the most part.) T-8's are lower wattage and more efficient lamps. With the right ballast and controls they can also be dimmed if needed. T-12 lamps and magnetic ballasts WILL be going away. They are already gone (by legislation, due to energy efficiency) for new commercial installations, and will continue to disappear from the lighting landscape, replaced by T-8 and T-5 lamps and ballasts. "Shop lights" sold at low prices with T-12 lamps are generally very poor performing magnetic ballasts. Electronic ballasts for the most part are high quality, flicker free, very efficient power supplies.

Different colors of light (think warm white, cool white, daylight, etc.) are available in both T-12 and T-8 and are a function of the phosphors used in the lamp. This is the color temperature you will see referenced....lower number is "warmer", higher number is "cooler". CRI is the all important color rendering index... higher number brings you closer to natural light, or full spectrum. All lamps will favor some part of the spectrum more than others... incandescent (think 60 watt screw in bulb), halogen (still an incandescent but operating at a much higher color temperature ) fluorescent (available in different many different "colors") discharge lighting (HID, including sodium, mercury, metal halide)....

Energy savings... think first in lumens/watt... all lamps consume energy to illuminate and that will be the wattage of the bulb. However, only part of that energy is converted in light... the rest is heat. Not only do you need to think of energy savings in terms of watts used to create light, you must also consider the energy it takes to eliminate the heat... (and yes in the winter, the heat is nice, but it is not an efficient heat source).

Life... Look at the life ratings for the products and factor that into your cost base, if you want to see the full impact... halogens generally have much lower life ratings and the replacement costs can be high.... (bear in mind that life ratings are average life, not minimum life).

Diffuse vs raking light.... I like even workshop illumination for general workshop conditions.. few shadows, high illumination. For some tasks, especially carving, raking light is very very valuable. I have track fixtures mounted over my workbench and next to my lathe with adjustable halogen fixtures on them that I use when I need this additional light or raking light. I do not leave them on all the time.

So what color temp and CRI?? The higher color temp fluorescent and higer CRI bulbs will give you light most closely simulating daylight....Better than incandescent and better than just halogen. That said, nothing beats natural light.... As many windows and skylights as you can have, along with light painted walls and ceilings. I do have a few halogens that I turn on if I need spot illumination.

Next time you are in a grocery store, especially a large chain...look at the lighting... will normally be different over the produce aisle... They are using lights which make the fruits and vegtables look their best. In a good jewlery or furniture store, they will select very specific lighting to make the best advantage of the colors in their products (diamonds like brilliant white light...but that isn't the best for gold...)

There is a great deal more to the science of lighting and I have yet to see a really good article (some have come close - the last FWW article wasn't bad) on the subject of lighting in woodworking shops and schools.... One of these days I may find the time to consult with our experts and create a definitive article... In the meantime, there is good information on the sights of the major lighting companies, including the one I work for.

Find what works for you...very few absolutes... more light is better.... natural light is best....

And fret less about the lighting and enjoy woodworking!

Roger

disclaimer - I do work for a major lighting company that makes the bulbs (incandescent, fluorescent, hlaogen, discharge, LED), as well as the glass, the phosphors, the ballasts, the bases...... We make all of the different types of lighting, so I am not swayed by what we produce... only the science of lighting.