…in windowless rooms? –
DW is getting a promotion – but will be moving into a windowless room (high school classroom) – it is currently lighted with standard florescent fixtures in the suspended ceiling grid – there are plenty of fixtures that provide plenty of lumens – of standard issue florescent quality –
the powers that be are refurbishing the room – more outlets, tables, equipment, etc –
I am wondering about some kind of human friendly lighting that could be added – some fixture/strategy to ameliorate the florescent flicker and provide some kind of substitute for sunlight –
I’d appreciate any knowledge and suggestions –
D
Replies
Fluorescent is better than incandescent. But if possible one should get some "full spectrum" fluorescents installed -- ones with CRIs higher than 85 or so.
We've discussed this before I think - for me regular flourescent is not better than incandescent, it gives me a headache and makes me very grumpy. I have loads of high-priced flourescents all over my house, but I will always pick the incandescent for comfort. Give me a cheap incandescent over a medium priced flourescent any day.
But an incandescent doesn't simulate sunlight. Being in an interior room without sunlight simulation can really f you up.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
I had Daylight lamps from Sylvania,they were clear blue and the light was a bit whiter , sometimes I spot similar lamps that are inside frosted but have never tried those.
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The early "daylight" lamps were just bluish fluorescent lamps, and actually had fairly poor color rendition. Newer ones are better, but you can't really tell much from the name attached (and unfortunately many mfgrs don't list CRI on the packaging).
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
oops my fault, I should have said they were incandescent, I liked them for reading it seemed to increase the contrast.but I recall replacing some very high dollar lamps from Duro Test that were guaranteed to be a certain temp in print shop light tables, not a typical lamp by any means.
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The two relevant characteristics of a lamp are color temp and color rendering index. Color temp, of course, determines whether the lamp is reddish, white, or blue (I don't offhand recall typical color temps for each), while CRI roughly determines how full-spectrum the lamp is. Incandescants have good CRIs, but generally poor (reddish) color temps. (IIRC, a CRI above 85 is considered good.) Fluroescents have generally good color temps (sometimes too blue for many people) but poor CRIs. To increase the color temp of an incandescent you must raise the filament temperature, limiting lifetime. To improve the CRI of a fluorescent you must use more complex, expensive (and slightly less efficient) phosphors on the inside of the tube.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
I think at the time ..... late 80s.... those FL in the print shops were only classified by temp they might have had a CRI but I don't know for sureand were guaranteedas far as color rendition by the sole Mfr. Duro Test I want to say those tubes cost around $25 for one 8 'er
and customers got real ticked off if you broke one because of the $$ and the phosphors became airborne and landed on everything.
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The better lamps (used by artists) run $50-100 now, in a CFL package.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
>>those FL in the print shops were only classified by temp they might have had a CRI but I don't know for sure<<
They did, if it was a reputable shop -- 5000 degrees K., CRI 91+; Macbeth was another manufacturer of the bulbs and housings.
You could shoot daylight balanced color transparency film in the shops and, provided you did not exceed the recommended exposure times, color balance would be perfect.
Printing / photography industry standard viewing conditions.
Everybody, photographer, designer, plate maker and pressman, was viewing the original transparencies and the resulting offset printed images under the same viewing conditions - the question was always the same --- Do they match?
Yes - good to go - sign off on the press proof.
No, shop needed to rework the printing.
The original transparency was the "gold standard".
Jim
Never underestimate the value of a sharp pencil or good light.
I've been all day in interior rooms, I used to work in a PIII hot lab, and I went into computing so I could be in the air conditioned basements of buildings. When I worked in Michigan I would go months without seeing the light of day during the workday. Maybe that explains a lot :)
I'll still take incandescent over flourescent. The buzz and flicker of flourescent is hard on my system, and the spectrum isn't worth it. One high priced fixture would be OK (I have one on my desk that I use when it's really dark), but a room with them on all the time is difficult for me. I'll take working in darkness over flourescents. I am completely dreading the day when we can't have incandescent bulbs anymore - I may have to give up reading.
You might see about "grow lights"--they are full spectrum fluourescents used for growing plants (cops may raid the school though!). I've seen them in ag. supply catalogs and gardening places/catalogs.
They're likely too high in UV to be safe.
As I stood before the gates I realized that I never want to be as certain about anything as were the people who built this place. --Rabbi Sheila Peltz, on her visit to Auschwitz
DW has an alarm clock that simulates daylight from these folks. They also have false window boxes and portable daylight simulators. A little pricey, but some people swear by them.
http://www.biobrite.com/index.php
Replace the ceiling fixtures with fluorescent fixtures that have electronic ballasts. They don't flicker like the magnetic ballasts do because of an advanced technology. Ballasts are also rated for noise. Pick ballasts with a good sound rating.
As for the lamps ("tubes"), many manufacturers offer lamps with multiple phosphors that provide a fuller spectrum than the cheap cool white tubes that most places use. Like someone else said, choosing lamps with a high Color Rendering Index (CRI) is a good idea. At least 80 or so is good. Also, the color temperature is important. I personally like a color temperature around 3500. A lower color temperature, around 2700, is a very warm color like incandescents but looks a little odd in fluorescent. When you get up to 4100 or so the color looks bluish and harsh, like a Walmart. Daylight, up near 6000, really, to me, looks unnatural indoors, and I find it very unnerving.
Depending on the office layout if the ceiling fixtures were reduced in number to provide just soft lighting, and you supplemented with floor lamps or desk lamps with incandescents, you can create a very nice atmosphere. Having the ceiling lights a little on the dimmer side and supplementing with task lighting for desk work makes for less glare on computer screens and is easier on the eyes.
Some here have suggested very expensive lamps, but that is not necessary. In my old shop I used high Color Rendering Index (a CRI of 82) lamps from GE (GE SPX35). They were only about $3.50 each compared to about $1.50 for the cheap standard lamps. That was in 2000. So the price of good light is peanuts.