Flouorescent bulbs

[Travis Porter]

It is about time for me to order some fluorescent bulbs. Based on SteveD's recommendations, I think this is what I should go with balancing the cost. These are $2.79 each and you have to order a case of 30. Since I need about 15 right now, I don't mind the quantity. Anyone know of any better prices or have a better recommendation? I can't use 40W as my fixtures are only rated for I think 74W each.

F34/DX/RS/EW/ALTO Bulb
General Information
Product Number 266593
Ordering Code F34/DX/RS/EW/ALTO
Light Output 1,775 Lumens
Energy Used 34 Watts
Life 20,000 Avg. Hours
Volts
Bulb Shape T-12
Beam Spread
Base Medium Bipin (Base Types)
` Class and Filament
Diameter (in) 1.5
Length (in) 48
Finish Daylight
CRI 84
Color Temperature (Kelvin) 6500K
Brand Philips

 

[dave_the_woodworker]

Mike is right. 6500K is at the far end of the spectrum (short wavelength), very blue and probably gives off quite a bit in the UV range. I use 5000K fluorescent bulbs in my shop for color matching and the colors match what I see in filtered sunlight very well. For any given temperature light source get the highest CRI (color rendition index) that you can. This is a measure of how well it renders eight standard colors compared to a perfect reference lamp of the same color temperature. The CRI rating of 84 for the bulb you are looking at is very good.

I just ordered from bulbs.com. They seemed to have pretty good prices.

 

[jeff...]

I don't know much about the actual numbers of the bulbs and what they mean. But alternating cool whites and warm whites in each fixture will give a good spectrum of light in the shop.

 

[Steve D]

I wouldn't recommend intermixing the bulbs to achieve your results. Ideally you will get your best shop lighting in the 41K to 55K range with a high CRI rating. The CRI of 84 is pretty good for a fluorescent lamp. Mid day sunlight in the summer is around 5500 Kelvin. The three key details to consider are amount of light in footcandles (should be around 50fc in work areas and 100fc in finishing areas), color temperature (41K-55K) and CRI (the higher the better). Other factors that are important are uniformity of light (consistent, not pools of light), glare (too many glossy surfaces are bad) and reflectivity (white walls & ceiling, satin or semi-gloss and light colored floor).

 

[jeff...]

Steve D, I don't disagree with you. I think we all have our own personal preferences. I've experimented over the years with different kinds of fluorescent bulbs. When it comes color matching and touch-up, my personal preference is row of alternating cool and warm white fluorescents. Of course the best light is sunlight, but that's not always an option.


Also, I personally don't like light bouncing off the walls, floor and ceiling, it's blinding and very distracting to me. Since I work with a lot of gloss lacquer finishes, I like light that reflects off of what I'm working on and not anything else. A dusty shop floor, unpainted wood walls with big windows and maybe even sky lights, is where I feel most comfortable and do my best touch-up work...


I've have cases where I've done touch-up in the shop at night, the colors blended and looked great. In the morning when they drug the piece out to the loading dock and the sunlight hit it, it looked aweful. Take the piece back to the shop under the fluorescent lights and it looks great again. This problem is easily solved by alternating cool and warm white fluorescents in the shop, so you can color blend in the wide spectrum of light.


This is an interesting thread, I never knew there were so many elements to a fluorescent bulb.

Just my 2 cents...

 

[Travis Porter]

OK, what do you think of this type? I have yet to find 5500K in 34W. This is 5000K and is still within my pricing. I have a hard time believing there are fluorescent bulbs that can cost over 10 dollars each.

F34T12/850/EW ALTO Bulb
General Information
Product Number 142562
Ordering Code F34T12/850/EW ALTO
Light Output 2,385 Lumens
Energy Used 34 Watts
Life 20,000 Avg. Hours
Volts
Bulb Shape T-12
Beam Spread
Base Medium Bipin (Base Types)
` Class and Filament
Diameter (in) 1.5
Length (in) 48
Finish Bright White
CRI 82
Color Temperature (Kelvin) 5000K
Brand Philips

 

[NCPete]

Here is a question sort of relevant to this topic. Do T-8 fixtures offer a broader range of color/temp choices????

 

[Ozzie-x]

The 1775 and 2385 lumens on those lamps are really low. I haven't done ltg calcs on T12 lamps in years (we only specify T8's now), but I'm remembering 2850 lumens on the GE T12 34 watt wattmiser warm white lamps and I think the Sylvania/Osram lamps were similar. I don't have any of my lamp catalogs or cd's here but can look it up tomorrow. Usually the warm white lamps produce a more lumens than the cool white's. I would recommend either warm white or cool white, either Sylvania/Osram or GE. I have cool whites in my shop and they're fine. The designer series lamps with funky kelvin ratings will gain you very little for your shop and cost maybe 3 times as much. DO NOT buy the shop light lamps, they're cheap and have very poor light output and quality, they can sell them cheap because they scrimp on the rare earth materials in the inside lamp coating.

 

[Steve D]

Like everything else, ymmv (your mileage may vary) much comes down to personal preference. CRI becomes a more critical factor than color temperature but the two go hand in hand. A high CRI rated lamp accurately represents all colors whether it is a warm or cool lamp. A low CRI lamp will skew the color towards red if warm and blue greens if cool. Most of our shops do not need this level of sophistication the way a print or paint shop does.

The eye sees best in evenly lit, low glare environments. Older people need more light to see fine detail than young people. IES (Illuminating Engineering Society) has recommended guidelines for proper lighting in different applications.

The points raised of lighting based upon where an object will be used is very valid. If you finish something under one lighting condition but use it somewhere else, it will look different. That is the reason the paint stores have the little gadget where you can hold the paint chip and change light sources to the type of lighting of the room to be painted.

I don't go to this level of sophistication in my own shop because I don't do that much color matching and when I do, I have the sample in my shop. That way the sample and the piece are being matched under the same lighting conditions. In my shop, my highest concerns are uniformity of light and amount of light. That is determined by the number and placement of fixtures. That being said, mine aren't evenly spaced because of obstructions, so I do the best I can.

I typically buy my lamps through local distributors and use the Phillips F32/T8/841ALTO. I get contractor pricing because I have friends in the business. They can be bought online in case quantities too. Most places carry it and it has a CRI of 86. All of my fixtures are T8 electronic ballast but that is another discussion entirely.....:lol:

 

[dozer]

I'm just going to duct tape a flash light to my head I think it would cause me less of a head ache than trying to remember all of this info when shopping for new lamps.....:lol: