Workshop Lighting - Warm White or Pure White?

[SteveyG]

Not true at all. CRI and Colour Temperature are not directly linked and incandescent lamps actually have a CRI of 100.

Which is wonderful if you like everything to be a bit yellow, but if you like accurate colour then LED daylight is better.

Why state that the LEDs have better colour rendering then? I'd also disagree with your comment about reliability. How many 'unreliable' incandescent lamps or even fluorescent lights do you encounter? I have some Philips MR16s that are 16 years old, and fluorescent strip lights that are a similar age.

Personally I find a good set of tri-phosphor tubes in my lab to be excellent, with local clamp on style lamps for close illumination. LEDs sold as daylight (~6000K) are generally the wrong colour temperature for accurate colour as the blue content is too high and lack the distinct peaks you'd find from a tri-phosphor tube. Between 4300K and 4800K is typically optimal as with TVs and projectors etc. 

[Zero999]

This is a personal preference thing.

It's more than that, it's a lifetime of indoctrination from lower temperature lights.

No, it's just natural to have lower temperature lights in more relaxing environments such as the lounge and bedroom. It probably goes back further than incandescents, when people had to light fires for light.

Of course in a working in environment, higher colour temperature light, as near to daylight as possible is preferable to most people.

It's just bad to have high colour temperature installed everywhere, especially in the bedroom it can cause health problems. It's just not natural to be exposed to daylight 24/7.

The problem with the supposed daylight simulation lamps is they're not light daylight, as there's a huge peak in the blue part of the spectrum, a dip just between the blue and green and a cut off in the orange end of the spectrum, leaving reds suppressed. It's also no where near bright enough, so tends to look dull and greyish rather than true white.

[IanB]

Why state that the LEDs have better colour rendering then?

Because they do? CRI is based on incandescent bulbs, not on how well a certain light renders certain colours. I think you are confusing the two.

I'd also disagree with your comment about reliability. How many 'unreliable' incandescent lamps or even fluorescent lights do you encounter? I have some Philips MR16s that are 16 years old, and fluorescent strip lights that are a similar age.

Anecdotal evidence. The LED bulbs I buy have a five year warranty, and most incandescents are rated for less than that if you use them regularly (1000 hours). There is also the rather low on/off cycle limit, compared to 50k typical on LEDs. Fluorescent lights fail al the time, we have the ones in our office replaced regularly and they flicker badly, but I can't be bothered to look for data right now.

Do you have any data that contradicts this?

CRI is "Colour Rendering Index". It is based on how well a light source renders colours. A high CRI lamp will have a balanced output over the whole light spectrum without any pronounced peaks or valleys at any particular frequency.

I have many incandescent bulbs in my house that have been installed for over ten years and used daily without replacement. When you can say the same thing about CFL or LED lamps then we can talk.

[SteveyG]

Because they do? CRI is based on incandescent bulbs, not on how well a certain light renders certain colours. I think you are confusing the two.

Think about what you're saying for a moment. CRI is high for an incandescent lamp because they emit a broad spectrum of light across the entire visible range.
An LED generally has a blue spike and a peak around yellow which fools the eye into thinking it's white light, but colours between the blue peak and yellow peak and colour above the red peak will never be as well rendered unless the spectrum is broadened.

[Zero999]

CRI is "Colour Rendering Index". It is based on how well a light source renders colours. A high CRI lamp will have a balanced output over the whole light spectrum without any pronounced peaks or valleys at any particular frequency.

I have many incandescent bulbs in my house that have been installed for over ten years and used daily without replacement. When you can say the same thing about CFL or LED lamps then we can talk.

Well if you hardly ever run them at full brightness, then incandescents will last for a long time but they still costed you much more in electricity than the equivalent CFL.

Because they do? CRI is based on incandescent bulbs, not on how well a certain light renders certain colours. I think you are confusing the two.

Think about what you're saying for a moment. CRI is high for an incandescent lamp because they emit a broad spectrum of light across the entire visible range.
An LED generally has a blue spike and a peak around yellow which fools the eye into thinking it's white light, but colours between the blue peak and yellow peak and colour above the red peak will never be as well rendered unless the spectrum is broadened.

For a start. Not all CFLs and LEDs are created equal. Some have a better spectrum than others. It depends on the LED dies and or phosphors used. Some LEDs have excellent colour rendering properties because they include a red die, in addition to the usual blue LED and phosphor.

There may be no peaks or valleys in the output of an incandescent. The spectrum may be consistent across the visible range with no peaks or troughs but it doesn't change the fact it is deficient in the shorter wavelengths, making blue objects appear more black.

[SteveyG]

CRI is "Colour Rendering Index". It is based on how well a light source renders colours. A high CRI lamp will have a balanced output over the whole light spectrum without any pronounced peaks or valleys at any particular frequency.

I have many incandescent bulbs in my house that have been installed for over ten years and used daily without replacement. When you can say the same thing about CFL or LED lamps then we can talk.

Well if you hardly ever run them at full brightness, then incandescents will last for a long time but they still costed you much more in electricity than the equivalent CFL.

I don't think he said anywhere he wasn't running them at full brightness? I've never used dimmer switches yet the incandescents have lasted an order of magnitude longer than a lot of the CFLs that I've used, including some £10/pc Sylvania ones.

I have some T5 fittings in the workshop that have Philips 93CRI lamps in them, but the control gear has failed twice (£90 each) which have offset the cost savings... They are great tubes though.

 

[Zero999]

I don't think he said anywhere he wasn't running them at full brightness?

It was in a different thread:
https://www.eevblog.com/forum/beginners/ac-soft-start-incandescent-lamp-switch/msg336720/#msg336720

The modern world is making it very difficult to have controllable lighting. Every light in my house is on a dimmer switch, and I run all my lights at 1/3 to 1/2 brightness. Putting the lights on full power now results in an "Ow! My eyes!" level of brightness.

Sadly, CFLs are invariably not dimmable (and the light has a horrible colour). LED lamps are sometimes dimmable, mostly not, but are hugely expensive. The halogen replacements for regular incan bulbs are not dimmable either. Halogen lamps need to be run at near full power to work properly. I have read that if you dim them they will have a shorter lifetime.

Fortunately I have found that bulbs run at half brightness last for years, so I can stockpile spare bulbs.

I've never used dimmer switches yet the incandescents have lasted an order of magnitude longer than a lot of the CFLs that I've used, including some £10/pc Sylvania ones.

I have some T5 fittings in the workshop that have Philips 93CRI lamps in them, but the control gear has failed twice (£90 each) which have offset the cost savings... They are great tubes though.

Yes, ballasts often go, quite often due to crappy capacitors. The lifetime is an average. It's a pain when things fail early but it doesn't mean it's the norm.

[IanB]

I don't think he said anywhere he wasn't running them at full brightness? I've never used dimmer switches yet the incandescents have lasted an order of magnitude longer than a lot of the CFLs that I've used, including some £10/pc Sylvania ones.

I do run them on dimmers--every light fixture in my house has a dimmer switch. Also, all of the light fixtures use special decorative bulbs of various kinds that are not replaceable with CFLs--CFLs don't fit.

[SteveyG]

You can't really buy high wattage incandescent bulbs in the EU any more, but if the OP can then maybe he should try comparing. Having said all that, the form factor of LED strips, or having lots of lower wattage LED bulbs distributed around the area and not producing too much heat, is likely to outweigh whatever preference an individual might have for incandescent lighting.

The trouble is, the LED strips and LED bulbs are usually the worst LEDs money can buy with rapidly degrading phosphor etc. If you'd said you'd made your own lights using high quality LEDs, or even better used something like a cluster of coloured Luxeon Z's with the all important 'lime' colour for filling in that area that's usually missing on white LEDs I could quite believe that they'd be preferable to other lighting sources.

[Zero999]

I don't think he said anywhere he wasn't running them at full brightness? I've never used dimmer switches yet the incandescents have lasted an order of magnitude longer than a lot of the CFLs that I've used, including some £10/pc Sylvania ones.

I have some T5 fittings in the workshop that have Philips 93CRI lamps in them, but the control gear has failed twice (£90 each) which have offset the cost savings... They are great tubes though.

Just thinking, you can protect yourself against this. When you fit the new lamp/ballast, then write the date on it and keep the receipt somewhere safe, possibly rolled in a small tube and stuck to the fitting. Then if it fails too so, go back to the retailer for a refund.

[ConKbot]

3500-4500k in office areas, 4000-5500k in lab/work areas, with ether good fluro tubes, (if work is paying for it, https://www.1000bulbs.com/product/4722/F-32T8TL950P.html it its your own pocket, https://www.1000bulbs.com/category/f32t8-fluorescent-tubes-5000k-800-series-phosphors/ ) or LED with a CRI > 80, ~500 lux for office areas, ~2-3000 lux for general work benches, and 10k lux on a soldering station or something with equally small parts.  Along with the expectation that anything you pick up for cheap will probably be constructed equally cheap.  ( '5000' lumen LED bulb thats 6500k, and costs $5.99 online?  Its probably going to be a lovely shade of blue, or blue-green)

[Zero999]

I don't think he said anywhere he wasn't running them at full brightness? I've never used dimmer switches yet the incandescents have lasted an order of magnitude longer than a lot of the CFLs that I've used, including some £10/pc Sylvania ones.

I do run them on dimmers--every light fixture in my house has a dimmer switch. Also, all of the light fixtures use special decorative bulbs of various kinds that are not replaceable with CFLs--CFLs don't fit.

These look good. It's compatible with a fairly wide range of dimmers and the colour temperature reduces when dimmed. They need to work on the aesthetics though.
http://www.lednovation.com/products/BR30_LED.asp

[Kjelt]

These look good. It's compatible with a fairly wide range of dimmers and the colour temperature reduces when dimmed. They need to work on the aesthetics though.
http://www.lednovation.com/products/BR30_LED.asp

Great so you have a new technology capable of much more than the old technology but you are now handicapping it to mimic the old technology, what a waste.
This is the same as that you add a noise and tick circuit to your streamer or other digital audio source because you liked that soo much on your record player.
If you want or need tunable white light sources buy a true tunable white light source. But for most people (as tests showed) they only need one colour for their workbench in the living room it is another story.

[steve30]

Warm white or cool white? Its hard to say for LEDs.

I have a fluorescent fixture with a dimmable ballast and a selection of tubes, so I can choose the colour temperature, CRI and brightness depending on what mood I'm in, what work I'm doing, the time of year etc.

Personally I've found warmer whites preferable in winter, and cooler whites preferable in summer. I do tend to find around 4000k to be a good compromise for most of the year. If I were choosing LEDs, I'd probably choose 4000k. I currently have 4000k fluorescent tubes, but I might change them back to 5400k in summer.

I recommend trying out different types and seeing what you like best .

[dannyf]

Even the warm whites may not be warm enough: I have to use a reddish shape on mine as they look too "cold" for me.

Every year, I do two lamp changes: incandescents to CFLs at the beginning of the summer and then CFLs to incandescents at beginning of the winter, trying to minimize my energy consumption,

[Artlav]

3000K LEDs in the evening or at night.
Cozy, pleasant light.

4200K Metal Halides at 2000 lux for work/filming/overcast winter days.
Look like sunlight not in early evening, banishes sleepiness and boosts the mood during winter (also good for seeing tiny details).

I tend to find low temperature light pleasant - the long, cold filament incandescent bulbs feel almost like fire, like candles.
Good light to think under.

[SteveyG]

Make your own. 

[Zero999]

Every year, I do two lamp changes: incandescents to CFLs at the beginning of the summer and then CFLs to incandescents at beginning of the winter, trying to minimize my energy consumption,

Although incandescents do contribute to heating your home in winter, I hope you're aware that it's less efficient than using a fuel such a natural gas or a heat pump, so unless you've got resistive heating (if so, it's probably a worthwhile investment upgrading), it's cheaper to keep the CFLs in all the time.

[ConKbot]

Every year, I do two lamp changes: incandescents to CFLs at the beginning of the summer and then CFLs to incandescents at beginning of the winter, trying to minimize my energy consumption,

Although incandescents do contribute to heating your home in winter, I hope you're aware that it's less efficient than using a fuel such a natural gas or a heat pump, so unless you've got resistive heating (if so, it's probably a worthwhile investment upgrading), it's cheaper to keep the CFLs in all the time.

Cost efficient, yes most definitely, its almost a shame to use electricity for heat in any application that doesnt need precise control.  Actual efficiency, a high end condensing natural gas furnace could be at most on par with the light bulbs (~98% efficiency) Vs the heat pumps which are way over 100% efficiency. (And now the physics and thermo people get a  bit of an eye twitch  )   


Now for the thermo

[Alisa]

NOTE: This message has been deleted by the forum moderator Simon for being against the forum rules and/or at the discretion of the moderator as being in the best interests of the forum community and the nature of the thread.
If you believe this to be in error, please contact the moderator involved.
An optional additional explanation is:

[KL27x]

I put a brighter but whiter flourescent bulb in my mag lamp at one point. I liked the color and the increased brightness, but I went back to the dimmer, yellow, fuller spectrum bulb. Even though it looks way dimmer, I found there was significantly less eye strain when I was working on small things.

I tried upgrading to a bright white LED mag lamp that had more lumens, but that was even worse. To be fair, I'm not sure what was worse between the color or the insufficient diffuser.  I repaired my flourescent mag lamp for the 4th time and put the LED lamp in the garage.

I also still use a halogen lamp. I repaired it when the lamp broke and swapped some parts out with a modern bulb lamp. They still sell the halogen bulbs, but the halogen lamps are no more for sale, here, due to being a fire hazard.

Now that I use the stereomicroscope for detail work, I don't really care so much about my general lighting. Whiter light appears brighter and does seem to have a positive effect on my mood.

[Simon]

I have spent the weekend installing LED lighting, individual modules rather than strips. As an experiment I purchased a 50/50 mix of warm white and pure white units to see which I liked the best (current consumption is the same) but which do you prefer, warm white or the full on pure white units?

Note, this is for general lighting, for close up work I still plan to rely on a desk light with an adjustable stand.

I prefer white. Warm white is a joke, it is actually yellow and your eyes auto white balance to make it look white (your brain does actually). I have visual stress and find yellow/red annoying so tend to prefer Bluer lighting. 4200K absolute minimum, preferably 5500K.

LED lights have been a miracle to my life and I was really really happy when the office lights at work got changed for white LED. I even tend to reduce the RED on my monitors but that is just me.

I think the term warm white was a bit of marketing to cover the fact that getting a white light once was not cheap or possible.

[Calambres]

I find the higher the colour temperature, the brighter the light needs to be.

Many years ago, while reading about the yellow front lights in french cars, the author stated that the reason behind that colour selection was based upon a study that found  the human vision to be more sentitive to lower colour temperature, that is, you need less watts of yellow light to "see" the same amount than that of a standard incandescent light. That may well be the reason behind your perception.

Personally, I cannot stand the white leds. I hate them. Don't know why but that kind of light makes me feel very uncomfortable.

[Simon]

I think beyond 4200K all lights start to look positively white and after 5500K it is going into blue, again our brains correct. I suspect that although every one differs in their individual perception there will be a range of colour that the brain can adjust for after which it becomes a problem with skewed colours. I am specifically skewed to over reacting to red so blue is good for me as it put's in the necessary offset. My minimum requirement to see a light as white is 4200K, I can tell you the colour temperature of lights between 2700 and 4200K as i can see their actual colour, but even I dislike too much blue.

[Synthtech]

I can’t deal with hard “daylight” temperature fluorescent lighting or CFL’s in my workspace, they are too actinic, they feel like the lighting equivalent of listening to an MP3.

The exception being that I keep a very bright daylight LED arm mounted lamp at each work area so that when I need that hard white light with too much blue in it for certain jobs it’s right there.

Don’t even get me started about low quality domestic CFL spiral bulbs that have too much green in their spectrum.