Author Topic: Workshop Lighting - Warm White or Pure White?  (Read 19925 times)

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Offline Simon

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #50 on: January 07, 2019, 08:19:49 pm »
i think the problem is that fluorescent technology cannot easily achieve the right light colour. That is why LED's are a godsend for me as they tend to be bluer anywag but they also have a fuller bodied white daylight colour. I have tried daylight CFL's and they were awful producing low light levels as they clearly lack some vital colour although were white enough for me to see as whiteish they did not seem to actually illuminate.

4200K I think is the limit for CFL, 3500K was actually tolerable. I think 2700K was a catchall classification for any old shit that was just yellow in colour but they only had the 2700K box to tick.
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Online nctnico

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #51 on: January 07, 2019, 09:06:35 pm »
Look at CRI numbers when buying CFL. Some are quite good (like Philips TLD mast 900 series) but you likely don't find these in the local hadware store.
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Offline Psi

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #52 on: January 07, 2019, 10:40:38 pm »
I tried two 50W 5600k YUJI leds in my lab, quite nice but i think it would be better a little warmer.

They only make 5600k and 3200k in the 50W package so i think what i'll do is get a pack of 3200k (they come in lot of two).

Then i can swap one 5600k in the lab with a 3200k.
That should give be 100W at around 4000k.  I can also dim one to get some color temp adjustments if needed.
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Online Kjelt

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #53 on: January 07, 2019, 11:44:23 pm »
Rule of thumb for most consumers:

2700K very warm white   Kitchen / Bedroom
3000K warm white          Living Room / Bedroom
4000K white                   Workplace / Study/ Office / Machinery
5000K + above               If needed for color matching or plants etc. etc. not preferred for normal consumers.

If you need different kinds of white on the same spot during the day for instance in the living room / study  or bedroom there are "tunable white" fixtures that let you choose between 2700K and 4000K. These usually have 2700K and 4000K leds and two drivers that dim according to the setting.
 
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Online rdl

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #54 on: January 08, 2019, 12:10:37 am »
The vast majority of the economical. single color bulbs are either 2700K (or thereabouts) or 5500K. I really don't understand the lack of variety. The 2700K is fine for living areas, but a bit too yellow for anything else. They obviously chose this color so the new LED "bulbs" would look like incandescent. As far as I'm concerned, 5500K is just about too blue for anything. I've seen 3000K becoming more common, but I found that still too yellow for my work area. I finally found some 4000K "shop lights" and they're pretty good, but I haven't seen that color in bulb form.
 

Offline Simon

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #55 on: January 08, 2019, 12:18:30 am »
Yea, we finally found a better technology than CFL and use it to replicate the main defect of CFL, carry on making yellow lights. Personally i suspect that many CFL's marketed as 2700K were below.
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Online GreyWoolfe

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #56 on: January 08, 2019, 12:35:23 am »
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.

I'm with you.  I had fluorescent over my workbench.  I now have 5,000K 6 bulb LED fixtures and I am much happier with my lighting.  Very bright on my bench but doesn't wash out the displays on all the toys or the monitor.  All the other lights in my office are now also LED so the savings on the electric bill are a bonus above me seeing better.
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Offline Simon

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #57 on: January 08, 2019, 12:39:50 am »
Well LED's are being praised for the reduction in power usage in the UK. I think realistically it's a mix of all commercial items being more and more efficient either to suit regulations or as a natural evolution of electronics.

Of course the media are ignorant. I use the same wattage in LED than CFL. I am just happier.
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Online coppice

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #58 on: January 08, 2019, 01:47:56 am »
i think the problem is that fluorescent technology cannot easily achieve the right light colour.
The light output from fluorescent lights has one serious drawback - the two main mercury lines are suppressed by the envelope, but are still quite strong in the output spectrum. Apart from that, the colour is as good as you pay for. Tube makers typically produce 20 or more finely tuned colour profiles for a range of applications, but most places just stock a vaguely daylight and a vaguely warm white colour. These are quite high efficiency, and have a pretty reasonable spectrum for general purpose applications. Tubes from good makers are constantly monitored to ensure the spectrum of the phosphor mix stays within fairly tight limits. At the other extreme, the colour usually called "graphic" is intended for graphic arts applications. It has a more tightly controlled spectrum, thicker glass to suppress the mercury lines more, but rather poor efficiency.

If, say, a clothing store buys the wrong tubes, they get a flood of "it didn't look this colour when I bought it" returns, so they are very sensitive to fluorescent tubes being accurate. When I did a summer job in Thorn Lighting's colorimetry lab in the 70s, a purchasing executive at M&S was fired for screwing up their group wide lighting orders, because of the flood of returns it caused.
 
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Offline Edison

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #59 on: January 08, 2019, 02:16:05 am »
At work is the most suitable daylight that is about 4000K
When using 2700 - 3000K (light bulb), more power is required for the same luminosity as 4000K.
6000K light is not suitable for work - tired eyes.
It is important however CRI (CRI - color rendering index) for our purposes should not be less than 85
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Online Kjelt

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #60 on: January 08, 2019, 02:52:39 am »
Yea, we finally found a better technology than CFL and use it to replicate the main defect of CFL, carry on making yellow lights. Personally i suspect that many CFL's marketed as 2700K were below.
Sorry this is a nonsense statement. The drawback of CFL was not the colourtemperature because you could choose that such that all colours even RGB were available. I can't help you never went further than your supermarket to get a CFL.

The main drawback of CFL was with cold temperatures problems starting, the older ones with the copper/iron ballast were getting a bit hot and when the starter was older had also problems igniting. But the modern TL5 for instance with electronic drivers can still compete with Led and is in many cases superior to cheap led fixtures from the far east.

The biggest advantage for LED over CFL is dimmable and lifetime,
CFL's have big issues when dimmed <10%, the filaments then get more current to compensate for the colder plasma and shorten their lifespan significantly.
« Last Edit: January 08, 2019, 02:54:39 am by Kjelt »
 
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Offline Simon

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #61 on: January 08, 2019, 03:16:13 am »
my personal experience with CFL that they were yellow, or yellow or yellow or grey but called "daylight" and needed to be 2x the power to see by. Yes I searched. Most vendors won't even tell you the colour temperature.
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Offline Edison

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #62 on: January 08, 2019, 05:32:33 am »
The biggest advantage for LED over CFL is dimmable and lifetime,
CFL's have big issues when dimmed <10%, the filaments then get more current to compensate for the colder plasma and shorten their lifespan significantly.
CFL are dimmed by special ballasts, start at 100% and then dim the brightness - very short action

« Last Edit: January 08, 2019, 05:34:32 am by Edison »
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Online Kjelt

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #63 on: January 08, 2019, 05:54:14 am »
The biggest advantage for LED over CFL is dimmable and lifetime,
CFL's have big issues when dimmed <10%, the filaments then get more current to compensate for the colder plasma and shorten their lifespan significantly.
CFL are dimmed by special ballasts, start at 100% and then dim the brightness - very short action
Yes there are three currents , two through the filaments used for pre heating and during dimming and one through the plasma after ignition.
My point if you dim a cfl below 10-15% the current through the plasma reaches a critical point where the plasma cools to much down to keep the arc going and it will shutdown. To mitigate the currents through the filaments are increased compensating for the plasma drop in temperature. Side effect the lifespan decreases significantly.
TL lights that have a EOL of 20000 hours when not dimmed can drop to 2000 hours if continuously dimmed below 10%.
 
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Offline Edison

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #64 on: January 08, 2019, 09:50:25 am »
I use industrial LED strip 24V  14W/m  4000K  2700lm/m  CRI 90  (1x1,5m + 1m) is not-dimmable - each cut has  current source instead of  resistors
I have my own sun  :-DD
« Last Edit: January 08, 2019, 09:52:16 am by Edison »
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Offline aix

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #65 on: January 08, 2019, 12:27:15 pm »
I've been experimenting with IKEA Trådfri "white spectrum" LED lights. They're switchable between 2200K, 2700K and 4000K.

The first impression is pretty good, although the jury is still out on whether wireless (ZigBee) control is a good idea.

Examples:
 

Offline Brumby

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #66 on: January 08, 2019, 04:21:48 pm »
I found some 4100ºK CFLs worked for me for my purposes.  No idea of the CRI, but works for general task lighting and photography.  My photographic setup is for internet publication - so colour accuracy is a bit of a crap shoot once it is published, but up until then, I have been able to get acceptable results.

Saw them on a clearance special a few years ago, so I stocked up.  No plans on reviewing the lighting until the stock levels dwindle or some major opportunity presents itself.

Rule of thumb for most consumers:

2700K very warm white   Kitchen

Oh hell no.  The kitchen is the most dangerous room in the house - proper task lighting is essential.  Start at 4000ºK and go up.
 

Online maginnovision

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #67 on: January 08, 2019, 04:33:01 pm »
I use 5000k pretty much everywhere.
 

Offline KL27x

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #68 on: January 09, 2019, 05:03:55 am »
Quote
my personal experience with CFL that they were yellow, or yellow or yellow or grey but called "daylight" and needed to be 2x the power to see by
This is exactly my first impression. But when looking at tiny detais - say, soldering and inspecting a PCB -  I found that even with "half the light," the warm spectrum CFL does a better job for my eyes.

Many people do most of their work on a computer and through paperwork. I am terrible with (wanting to do) paperwork. Maybe it's my lighting.

I think perhaps when viewing physical 3 dimensional objects made of composite materials, a narrow spectrum light (brighter/whiter CFL/LED) maybe has more extreme constrast variation. As in some materials/surfaces/angles will reflect much more of this narrow bandwidth of light than other materials/surfaces/angles. And with a warmer, fuller spectrum, you get a more consistent contrast without the hot spots and relative dim spots that cause the eye strain.
« Last Edit: January 09, 2019, 05:14:44 am by KL27x »
 

Offline Red Squirrel

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #69 on: January 09, 2019, 05:12:32 am »
I prefer "cool white" or "daylight", at least for when I need general lighting.  I find for the same lumens, it is brighter than warm white. 

For stuff like Christmas lights or other "decorative" lighting or living room, etc then warm looks better.

I also have a theory, it's totally from a non medical background so no idea how accurate it is, but I think if you go with "daylight" it may even improve mood and help you be more productive.  This theory is not really based on anything other than some research on depression when I went through it, and it talked about blue light helping seratonin levels.  Daylight bulbs will have more blue in it.  When I redo my office/lab lighting I might actually add blue LED strips too that I can switch separately.  Probably going to go with T8 bulbs, I find LED fixtures a bit limiting as you can't really pick the color temperature.   Ex: the fixture you like may not come in the color temperature you want.  Most of the ones at Home Depot are warm white.
 

Offline Red Squirrel

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #70 on: January 09, 2019, 05:13:54 am »
I found some 4100ºK CFLs worked for me for my purposes.  No idea of the CRI, but works for general task lighting and photography.  My photographic setup is for internet publication - so colour accuracy is a bit of a crap shoot once it is published, but up until then, I have been able to get acceptable results.

Saw them on a clearance special a few years ago, so I stocked up.  No plans on reviewing the lighting until the stock levels dwindle or some major opportunity presents itself.

Rule of thumb for most consumers:

2700K very warm white   Kitchen

Oh hell no.  The kitchen is the most dangerous room in the house - proper task lighting is essential.  Start at 4000ºK and go up.

Bad lighting in kitchen may also make it harder to judge if food is cooked properly.
 

Offline KL27x

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #71 on: January 09, 2019, 05:16:19 am »
White light should contain a full spectrum of colors, shouldn't it? How is it that "white light" is a narrower spectrum than "yellower" light? Or do I have it wrong?

Maybe it's that the most efficient CFL/LEDs in terms of lumen output are highly efficient because they use a narrow bandwidth that happens to be good at this metric. So high output, brighter lights tend to be narrower spectrum?
« Last Edit: January 09, 2019, 05:19:46 am by KL27x »
 

Online Kjelt

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #72 on: January 09, 2019, 05:38:52 am »
Rule of thumb for most consumers:
2700K very warm white   Kitchen
Oh hell no.  The kitchen is the most dangerous room in the house - proper task lighting is essential.  Start at 4000ºK and go up.
Yes for the workbench where you cut the food etc. I was just saying that an average customers esp. women want a cosy yellowish light in the kitchen, that pro chefs in their pro kitchen use 4000K is because it is a workplace for them  :)
 

Online Kjelt

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #73 on: January 09, 2019, 05:42:39 am »
White light should contain a full spectrum of colors, shouldn't it? How is it that "white light" is a narrower spectrum than "yellower" light? Or do I have it wrong
Read this and be enlightened  :)
https://en.wikipedia.org/wiki/Black-body_radiation
 

Offline Brumby

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Re: Workshop Lighting - Warm White or Pure White?
« Reply #74 on: January 09, 2019, 01:42:21 pm »
Rule of thumb for most consumers:
2700K very warm white   Kitchen
Oh hell no.  The kitchen is the most dangerous room in the house - proper task lighting is essential.  Start at 4000ºK and go up.
Yes for the workbench where you cut the food etc. I was just saying that an average customers esp. women want a cosy yellowish light in the kitchen, that pro chefs in their pro kitchen use 4000K is because it is a workplace for them  :)

We may have to agree to disagree on the preference of the "average customer".

I would like to introduce you to the keeper of the kitchen here....

I installed a 2m strip of 5000ºK LEDs above her main work area with a couple of cable ties as a temporary setup to see if she liked it.  That was over a year ago - and I haven't been allowed to take it down in order to make a more permanent solution.
« Last Edit: January 09, 2019, 01:44:24 pm by Brumby »
 


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