warm white or cool white for a workbench light ? - Page 1
Forum section: electronics / projects

author: Warhawk
author_rank: Frequent Contributor
timestamp: September 27, 2014, 11:49:15 am
content: Hi guys,I am about to finish my new workplace and want to use LED stripes in Al profile for a workbench light.Which light color do you prefer for soldering, measurements and general work ?edit:This is a bench I am working on. Living in an apartment does not allow me having something more fancier but it still does the job.I would like to add two LED stripes in this aluminum profile:http://www.t-led.cz/led-profil-tube-nastennytogether with this PS:http://www.t-led.cz/led-zdroj-12v-12w(EN datasheet is nice:http://www.t-led.cz/media/document/katalogovy-list-led-zdroj-tlps-12w-.pdf)I plan to place it in a two-rows configuration on the bottom of the horizontal shelf, of course.Local shop offers this:cold white 6000-6500K, 410 lmday white 4000-4500K, 390 lmwarm white 2900-3200K, 365 lm

author: SeanB
author_rank: Super Contributor
timestamp: September 27, 2014, 12:02:26 pm
content: For efficiency the cool white is about the best, but has poorer colour rendition for doing things like reading colour codes. You probably want a neutral white light, or a near daylight light for that, or use RGB lighting to make white in the colour you want. Mine is a mix of cool white and warm white, the extra red helps with seeing colours.

author: ondreji
author_rank: Contributor
timestamp: September 27, 2014, 12:05:06 pm
content: I like day / white -- colour temperature should be between 5500K and 6500K

author: sonic2000gr
author_rank: Newbie
timestamp: September 27, 2014, 12:18:40 pm
content: Having finished my workbench recently, I opted for cool white LED lighting. It helps a lot on working with small components although it is somewhat difficult to read color codes sometimes. A magnifying lens helps though

author: rdl
author_rank: Super Contributor
timestamp: September 27, 2014, 12:59:44 pm
content: I opted for Daylight White, but only because I already had a very bright fluorescent light that color. Otherwise I would have chosen something less blue. There is research indicating light that is too blue can disrupt sleep patterns. The US Government has recommended 4100K CCT for roadway lighting. Philips has acknowledged that a warmer color is often preferred for residential area public lighting. In your workspace, it's up to you of course.

author: wraper
author_rank: Unknown
timestamp: September 27, 2014, 01:05:59 pm
content: Would suggest to look actual spectrum for particular model in the datasheet. As white leds are a blue leds with a phosphor on top, spectrum is very awful usually and is a mix of blue and yellow. With such a leds lighted objects will look weird. Personally wouldn't use led strips at all because of the poor color reproduction (unless I could find good ones) and just use led lamps from a good manufacturer.

author: German_EE
author_rank: Super Contributor
timestamp: September 27, 2014, 01:29:47 pm
content: I tried using LED lighting on my workbench (warm white and cool white) but got some very strange results when I had to read resistor color codes. Maybe it was the cheap LED lights, I don't know, but I ended up switching back to conventional incandescent bulbs.

author: SeanB
author_rank: Super Contributor
timestamp: September 27, 2014, 01:45:44 pm
content: That is why I use a blend of lights, as the cool white is very lacking in red and green. You probably want to buy a RGB strip and use it, they are quite bright and they do give a correct colour spectrum for reading, though you will find they are not neutral in the white, but that can be trimmed if you toss the simple controller and do your own.

author: rdl
author_rank: Super Contributor
timestamp: September 27, 2014, 02:10:57 pm
content: Often, cheap, poorly colored paint is used to mark resistors these days, to the point where I find them hard to read under most any light. Red and orange look the same, and green, purple, blue and brown all just look like some shade of black. It would be better if they'd just start laser marking them with the actual numbers.

author: MK
author_rank: Regular Contributor
timestamp: September 27, 2014, 04:18:30 pm
content: Quote from: AcHmed99 on September 27, 2014, 12:27:13 pmDaylight corresponds to a hot source at 5600 Kelvin or so, but usually that is judged to be too blue, whereas evening light may have a colour temperature up over 10,000 Kelvin even though the brightness is down.

author: Lightages
author_rank: Unknown
timestamp: September 27, 2014, 04:54:08 pm
content: IMHO, do not use LED lights unless they are a known good spectrum. Cheap ones make very poor light. Try to use 4700K to 5600K fluorescent if you can. Fluorescent lights are not as efficient as LEDs but easier to get consistent color. Incandescent color temperature is really not great for working in detail.These are all my personal opinions of course but one thing is a fact. The more light the better (within reason) and the less shadows you have the better.

author: mike105105
author_rank: Contributor
timestamp: September 27, 2014, 05:49:44 pm
content: Between LED colors I think warm, but I would suggest compact florescent instead. If you search around you will find CF bulbs in between "warm" and "daylight", usually called "bright white". It is a nice real white, no yellow or blue. I get the 100w equiv ones at home depot or lowes.Edit:http://www.homedepot.com/p/EcoSmart-120W-Equivalent-Bright-White-3500K-Spiral-CFL-Light-Bulb-ES5M83035K/100663852?N=5yc1vZbmatZ1z0u18uMike

author: GreyWoolfe
author_rank: Unknown
timestamp: September 27, 2014, 06:27:05 pm
content: I have daylight deluxe bulbs in my 4ft, 4 bulb T-8 light fixture over my workbench. I like the light enough that I replaced the bulbs in 3 other light fixtures in the office/ham shack with the same daylight deluxe bulbs. No issue reading resistor color codes, I need a magnifier simply because my vision is sliding a bit downhill- the bi-focal part gets stronger all the time. The daylight deluxe flourescents are 6500K but they work fine for me. If I was going to go to LED, I would want the same color temp or as close to it as I could get.

author: rdl
author_rank: Super Contributor
timestamp: September 27, 2014, 07:23:31 pm
content: I was just at Home Depot and saw that Cree now has some LED bulbs with a CRI of 93, but at $6 more than the regular type. They were the warm white 2700K color.I almost bought a daylight 100 W= bulb to replace the 60 W= I bought a few weeks ago, but I decided $20 was just too much for a light bulb.I don't mind the daylight type in my work area, but I'd never put them in the living room or a bedroom.

author: GreyWoolfe
author_rank: Unknown
timestamp: September 27, 2014, 11:25:57 pm
content: Yes, the daylight deluxe are only for the office/workbench. All the CFL lights in the house are cool white. SWMBO would complain too much.

author: Warhawk
author_rank: Frequent Contributor
timestamp: September 28, 2014, 08:44:34 am
content: Interesting thoughts guys. I updated my first post so you may get better imagination what I need it for. Do you think it is a good idea to use a combination of both LED strip types ? I mean one row in a warm white and second one in a cold white.btw: I am a young fellow but my eyesight is already pretty much messed up. I don't read resistor color codes at all and use DMM every time...

author: ondreji
author_rank: Contributor
timestamp: September 28, 2014, 09:45:28 am
content: Quote from: AcHmed99 on September 27, 2014, 12:27:13 pmI use 6500K at the moment and yes -- that's little bit blue. Anyway, 6500k is still better than those yellowish lights (which are around 2700K?).

author: Kibi
author_rank: Unknown
timestamp: September 28, 2014, 10:17:51 am
content: I am using Cree CXA2011 4000K dies in my bench lighting setup. I am very pleased with them, I find the colour very comfortable for working under and I have never had any problems with identifying colours. I think using LEDs from a good manufacturer is the key to getting consistent, good quality light.

author: george graves
author_rank: Super Contributor
timestamp: September 28, 2014, 10:21:17 am
content: When your poll said "cool white" or "warm white".....your opinion of the colors and mind much be different. Very subjective.

author: Otto
author_rank: Newbie
timestamp: September 28, 2014, 03:55:19 pm
content: This is timely for me. I'm just looking into how I'm going to light my electronics workbench. It's interesting that so many different opinions have been expressed here, especially in regards to the desired color temperature of the light.That is what prompts me to ask: Does anybody here know of a relatively inexpensive way to measure the color temperature?

author: eneuro
author_rank: Super Contributor
timestamp: September 28, 2014, 04:56:09 pm
content: One can blend a few sources of light of diffrent temperatures using simply potentiometer and MCU driving those lights using PWM and filtering rectified AC so we have nice DC- you can get predefined nice light for diffrent situations, but only one pot to controll them allHowever, my first concern is always to remove any flickering in those lights, so of course custom PS if light sensor connected to scope gives such nasty lighting like for example classic light bulb in 230VAC 50Hz mainsI've made this small LDR based light sensor so I'm able even in the shop take my laptop, put this thing into microphone input, point it to light source and see if there are any mains 50Hz components (100Hz on thisxscopeas explained sometime ago why it is 100Hz flickering not 50Hz mains) in emited light which I hate

author: nanofrog
author_rank: Super Contributor
timestamp: September 29, 2014, 08:08:50 am
content: Accustomed to seeing Cool White as ~6000K - 6500K, and find it too blue for my tastes (so selected "LED other" in poll).I prefer 5000K (aka daylight or natural white), and have been using a Utilitech LED spotlight for over a year now with excellent results.Currently, I'm in the process of putting together a 5000K LED strip configuration for under shelf lighting to add more light/remove shadows from swing arm & overhead. Consists of 1 meter of Epistar 2835 LED strip (current listing), cut into two equal lengths for a split shelf configuration. Color is good thus far, but they're actually too bright (i.e. bit blinding), so I'm in the process of putting together a dedicated PSU and PWM dimmer (previous testing just done using a bench supply). Will be mounted to aluminum angle and attached to the bottom of the shelves.

author: Warhawk
author_rank: Frequent Contributor
timestamp: September 29, 2014, 08:23:25 am
content: Quote from: nanofrog on September 29, 2014, 08:08:50 amLook how Chinese placed 3M logo to the double stick tape but all of them are arranged to miss a small piece to make it legal...Man would think that it is a genuine 3M....bastards...just sayin'

author: nanofrog
author_rank: Super Contributor
timestamp: September 29, 2014, 09:00:48 am
content: Quote from: Warhawk on September 29, 2014, 08:23:25 amWhat do you expect for 10 bucks? Miracles?!?Oh, and I only paid $7.Price went up right after.

author: Warhawk
author_rank: Frequent Contributor
timestamp: September 29, 2014, 10:05:20 am
content: Quote from: nanofrog on September 29, 2014, 09:00:48 amNo miracles, I simply don't like it and have a problem to accept it. O0It is like fake transistors, MCUs, brake pads, batteries etc.People who know nothing about these practices often yell aloud"I had 3M before and it sucks"or"I've just got a genuine iPhone charger from ebay for 2 bucks and it is exactly the same like original..."and other crazy shit. It may cost us a job in future. I mean when a cheap Chinese labor, lack of work safety, employee rights in hand with a western-world ignorance and consumerism ruin quality products because of cost.I've just been thinking aloud.

author: Warhawk
author_rank: Frequent Contributor
timestamp: September 29, 2014, 10:07:26 am
content: Quote from: george graves on September 28, 2014, 10:21:17 amYou are right. I should have added more details. I am going to update a first post. I decided to buy "day-white" - 4000-4500K

author: Kjelt
author_rank: Super Contributor
timestamp: September 29, 2014, 12:45:17 pm
content: rule of thumb for indoor use:2700K Kitchen3000K Living Room4000K Working Area.

author: metalphreak
author_rank: Frequent Contributor
timestamp: September 29, 2014, 02:21:48 pm
content: 4000K is the standard for office lighting and is probably what you want.If you deal with anything with high detailed colour contrasts, you want a high CRI (Colour Rendering Index), which I would not trust any of the stated CRI values from the cheap brands.

author: Kjelt
author_rank: Super Contributor
timestamp: September 29, 2014, 02:40:45 pm
content: Be carefull, the CRI was defined for halogen lamps (broad spectrum) not for LEDs (narrow spectrum) so untill they define a new standard the CRI is not much use and will only be high for those leds that use phosphor (broad spectrum).

author: tszaboo
author_rank: Super Contributor
timestamp: September 29, 2014, 03:07:59 pm
content: I would not use LEDs at all for the place where I solder. It makes my eyes bleed. It is awful for that. Actually If I was about to build my own lab, I would use a 12V battery charged overnight and multiple 12V incandescent lightbulb. EMI away you go, stress away you go.

author: Warhawk
author_rank: Frequent Contributor
timestamp: September 29, 2014, 03:44:01 pm
content: Quote from: NANDBlog on September 29, 2014, 03:07:59 pmSure, I wanted to make my own power supply for LEDs because of EMI.Then I realized - Rigol, Laptop - both have a DCDC inside.The supply I linked here before is well specified (abnormally for this class) and I somehow feel it might be better than others.

author: tszaboo
author_rank: Super Contributor
timestamp: September 29, 2014, 08:43:11 pm
content: Quote from: Warhawk on September 29, 2014, 03:44:01 pmSorry, I thought you wanted to measure something and have the lights on at the same time.I hate when the scope makes false triggers. That is why I sit through all measurement (EEVblog #14 anyone?)

author: Warhawk
author_rank: Frequent Contributor
timestamp: September 30, 2014, 05:29:14 pm
content: Quote from: NANDBlog on September 29, 2014, 08:43:11 pmSorry, I did not get it :-)I just wanted to say that my idea, making a nice and clean linear PSU for LEDs, is not worth the effort. Even if I designed and made it, I would still have other noise sources somewhere else.

author: Things
author_rank: Regular Contributor
timestamp: October 01, 2014, 12:58:45 am
content: I find 4000K to be the perfect mix between not too yellow and not too blue. It's more on the yellow side than blue, but you wouldn't really call it yellow.