Night time indoor daylight?

I need more light in my garage. I spend too much time in there working with no windows under crappy fluorescent lighting. Currently I have three 4' shoplights in a 25x25 space.

I want to create the most realistic daylight possible. I was thinking I'd buy several more 4' fixtures and mount one about every five feet, maybe a few more.

What color temperature bulbs should I use to replicate real sunlight? I bought some Philips "Daylight Deluxe" bulbs, 6500k, but it's a blue-white color that looks nothing like daylight to me. My other fixture has Philips "Cool White" bulbs, 4100k, that seems more like natural light to me. There are of course other temperatures available. If I buy more fixtures, what bulbs should I use? Should I mix different colors together?

Or- would it help if I added some of those "natural light" incandescent bulbs they're selling now? Efficiency is not a concern, only what it takes to make real daylight.

I have 2 plant tubes, 2 regular tubes, and 300W of incandescents in half of my garage and I think that's pretty good. I've never had any problems with getting sleepy (like happens to me with straight incan) nor with eye fatigue (like with straight cool flourescents), but YMMV.

Daylight incandescent bulbs are worthless IMO. Just colored glass reducing output so the blues aren't so overpowered.

Four foot 40 watts, is that correct? (Also 34 Watt energy saver). If so go find some GE Sunshine lamps, these are 5000 K and the CRI is 90, so they do replicate daylight very well. Note these are only available in 40 watt, but 34 watt energy savers are retrofits for 40 watt anyway.

Phillips daylight bulb are excellent, good colour temperature, and high CRI.
My personal choice.

Its weird how our eyes perceive light.

It sounds like your after a warmer glow akin to incans. If you already have some bulbs, maybe mix some low CCT bulbs in.

Phillips daylight bulb are excellent, good colour temperature, and high CRI.

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The OP already said he didn't like them, and I agree with him.

Also, the Phillips bulb is migraine inducing 84 CRI, which is hardly "high CRI" in my book. If you want a decent looking 5000K bulb then..

http://www.blanksfab.com/fullspec/lumiprice.htm

My other fixture has Philips "Cool White" bulbs, 4100k, that seems more like natural light to me

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You answered your own question. 4100k is the subjective sweet spot for commercial light sources appearing 'neutral white', be it LED, fluorescent or other.

For work lighting, office lighting, data centers ('ve worked in dozens) etc., 4100k is really where you want to be. 3000-3500k might be ideal for the living room because of it's greater warmth, but for worklight 4100k is perfect.

As you've seen, retail 'Daylight' or 'Full Spectrum' bulbs at 5000k and higher look really bad...the kind of light you'd perform an autopsy with, but not much else. I use 40watters on my front porch to keep crack-heads off my lawn because they are so bright and ugly. The bad news is that they are marketed heavily because they are more efficient than warmer color temps. The good news is that 4100k fluorescents have become the common industry standard for worklight, and have been for awhile.

Just stick with 4000-4100k tubes (any brand should do), and you should get fairly neutral light that you prefer. Another suggestion is if your garage ceiling is white you can point some shoplights at the ceiling and this will create a diffuse, ambient fill that will mix well with your down firing shoplights.

these are 5000 K and the CRI is 90, so they do replicate daylight very well.

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Assuming you have the visual cortex of certain insects. 5000k CFL at 90 CRI looks anemic and cold/harsh. 5000k with any light source only looks decent if it's a VERY high CFL, like 98 or higher, and those bulbs aren't something you find locally.

I agree with blasterman. 4100k.
Direct/Indirect fixtures may help. But they need to be suspended. They'll let 10-20% light upwards, through slots in the top of the fixture. That's probably a bit more involved than it's worth though.

BatteryCharger said:

I need more light in my garage. I spend too much time in there working with no windows under crappy fluorescent lighting. Currently I have three 4' shoplights in a 25x25 space.

I want to create the most realistic daylight possible. I was thinking I'd buy several more 4' fixtures and mount one about every five feet, maybe a few more.

What color temperature bulbs should I use to replicate real sunlight? I bought some Philips "Daylight Deluxe" bulbs, 6500k, but it's a blue-white color that looks nothing like daylight to me. My other fixture has Philips "Cool White" bulbs, 4100k, that seems more like natural light to me. There are of course other temperatures available. If I buy more fixtures, what bulbs should I use? Should I mix different colors together?

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6500k may look okay if the spectrum is continuous, and more importantly, if illumance is EXTREMELY high, as in, the ~100,000 lux of actual daylight. Your garage is 60 square meters. You'd need minimum 30 tubes to achieve even 1% of peak daylight illuminance.

Generally speaking, our eyes perceive lower color temperatures as being "more pleasant" at lower illuminances. That's why daylight might seem pleasant outside, and not so nice on overcast days (or coming from artificial 6500k lamps at typical indoor illuminance levels). Here is a graphic from Wikipedia illustrating my point:


Light at around 4200k appears to be "acceptable" across a very broad range of illuminances, so it's good for a lot of situations.

Another attribute of daylight I've been toying with reproducing is this:

daylight is not a homogenous color temp and intensity. There are some direct ray from the sun (at lower color temp) and indirect rays from the sky (at higher color temp). I've toyed with 5000k indirect / 3500k direct before and like the results. Though for your purposes, going with 4200k all around may be easier (and "on average" should be the same).

blasterman said:

Assuming you have the visual cortex of certain insects. 5000k CFL at 90 CRI looks anemic and cold/harsh. 5000k with any light source only looks decent if it's a VERY high CFL, like 98 or higher, and those bulbs aren't something you find locally.

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Big difference between 6500K and 5000K. 6500K can be bluish-white and harsh, especially given that most 6500K tubes have a not so great CRI. On the other hand 90+, 5000K looks much closer to sunlight than either 6500K which is too blue or 4100K which is too yellow. Also note that there are few 4100K tubes with CRI over 85. BTW, daylight is generally reserved for tubes in the 6500K area, sunlight for those in the 5000K area. Unless you're lighting very brightly 6500K generally looks strange to most people.

And if the OP is going to get more fixtures I'd recommend ditching the old school 40 watt T12 tubes completely. Chances are the existing fixtures have headache-inducing magnetic ballasts which flicker. No matter which tubes you use the light will be less than acceptable because of this. Get all new T8 fixtures with electronic ballasts and try either these 5000K tubes or these 5500K tubes. Finally, in a 25x25 foot space you're going to need at least a dozen 2-tube shoplights to get decent lighting levels. I have three such fixtures in my 7x11 workshop which is mostly white and I barely consider it acceptable.