What light bulb for computer room ceiling light?

The pleasant thing about CFL bulbs is they last for ages before needing replacement. Of course that means when they eventually do, I'm out of touch with where the current technology is!

So any recommendations for the ceiling light in a very small study (box room)? It's our computer room, so we don't need/want anything too bright. I do a lot of photo editing so having something without an obvious colour cast would be beneficial. A quick warm up time would be nice too. Absolutely needs to avoid flicker if possible!

Thanks!

I went with a couple of dimmable LED spots with White LEDs. However, if it is just a single light source and not two or more overlapping, it can make for some pretty harsh shadows - not ideal for studying.

Yeah it's single source and I definitely want to avoid shadows, as omni-directional as possible would be good.

After some more reading, I guess I want high CRI, around 600 lumen, and colour temp around 4500k. But I can't find anything hitting that :p LED seem to go for either very warm (2700K) or very cool (6000+K).

I went for a dimmable LED strip bulb. Seems to fit in a standard housing. Think the colour is around 5000K.

I take that back. It's 6000°K according to the sticker on the bulb, but their website says 5500°K: http://www.voltacon.com/t8-led-tubes

I've got a 20w 120cm one that puts out a decent amount for a small study.

Philips are my go-to brand. I've never been disappointed with their bulbs. For reference 2700K colour temperature is equivalent to incandescent bulbs, which I personally prefer in the home. If you want more natural colour tone search for daylight white.

Use their selector here:

http://www.philips.co.uk/c-m-li/choose-a-bulb/need-help

Yeah looks like I'll have to settle for 2700K, the philips daylight white type ones are a little too cold at 6K.

I'd rather 6000 over 2700 for photo editing. But I've seen a lot of LEDs around 3500K.

You could also paint your room cream to warm it up a bit with a 6000 light.

Try this

https://www.ledhut.co.uk/led-bulbs/b...placement.html

Or others from the same source.

I've used this company for about three years and all but one of the lamps in my house are LED from them.

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Originally Posted by peterb

Try this

https://www.ledhut.co.uk/led-bulbs/b...placement.html

Or others from the same source.

I've used this company for about three years and all but one of the lamps in my house are LED from them.

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Nice, thanks. How do you find their colours? They list the cool white as 5000K which might be ideal.

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Originally Posted by kalniel

Yeah it's single source and I definitely want to avoid shadows, as omni-directional as possible would be good.

After some more reading, I guess I want high CRI, around 600 lumen, and colour temp around 4500k. But I can't find anything hitting that :p LED seem to go for either very warm (2700K) or very cool (6000+K).

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CRI is a fairly dubious measurement. LEDs do tend to be better than flourescents were about generating reasonable CRI numbers but some of the budget bulbs can still be well out of whack. A new TM-30-15 standard was devised last year, but you probably won't see it on standard bulbs yet.

600 lumens isn't that bright, only around that of an 11W flourescent, and less than the 850 lumens of a 60W incandescent. It's not unreasonable, but know what you're getting.

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Originally Posted by kalniel

Nice, thanks. How do you find their colours? They list the cool white as 5000K which might be ideal.

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I have a 2700K in the ceiling pendant light in my study, and a 5000K in a desk lamp. A lot depends of the colour of the walls. White or pale pastel shades would be fine with 2700K, but darker colours may look a bit dingy.

Of course you could be one of each and use the one you don't use in your study somewhere else!

The filament lookalikes are very good in table lamps, the translucent cased ones (like the one I linked to) are better for ceiling pendants where the light is diffused by both the lamp and the shade.

I quite like what I think is B&Q's own brand Diall for LED lights. In fact I actually prefer them over an Osram one I tried for a couple of reasons;

Firstly, the Osram one projected most of the light down, leaving the ceiling very dull which I found unpleasant - the Diall one does a good job of lighting the room more evenly. The Diall one also seems to emit a much nicer i.e. higher CRI light.

The Osram one had what I found to be very noticeable flicker, IIRC it wasn't at 50Hz but something more akin to PWM flicker around a few hundred Hz. It also seemed to be emitting interference at around that frequency, strong enough to show up on my oscilloscope across the room.

The Diall one doesn't seem to have anything like PWM and is far more electrically quiet.

Of course I'm only comparing one lamp to another so it's probably not fair to sum up a whole brand based on that, but that's my experience anyway. I also purchased both of these lamps a number of years ago so they could have completely changed by now. But it's more important to try some and find one you like to install throughout your house as they're far less consumable than even CFLs given how long they last.

Osram do some good LED's and tesco stock them otherwise I have started to use Screwfix offerings (LAP) as they are quite good and don't flicker like the ones I saw from LED hut in a friends house.
Philips probably do the best but the price reflects that.

I've fitted around 60 to 70 lamps from LED Hut, most of them lumi-life and not had any problem with flicker. However non of them were dimmable versions.

Found what could be perfect:
http://www.weloveled.com/products/21...-neutral-white

9W, 860 lumen, and importantly, available in a 4000K setting. Slightly narrower beam angle of 240 degrees but it's a small room so that should be enough. Will update tonight.

edit: Not bad at all. I wouldn't want to go any cooler. It is very close to a day time shade, there's a slight blue-green cast but pretty sure that's the duck-egg walls/curtains rather than the bulb :p

The problem I had with standard bulb fittings was lumens and angle. Strip light solved that problem.

I do have Philips 100W equivilant bulbs in the lounge which are pretty spectacular, but they are warm-white.

I have those 100W equivalent Philips as well, best 100W incandescent equivalent I've used so far. 20W power usage, but worth every watt!

lighting in every room is key to ambience and well being

ma I suggest not just the ceiling lights.. but possibly another sort and direction of light?

example... an angle poise lamp....near or clamped too the desk over the keyboard is a very good thing for gaming and some styles of work

the bulb is secondary to the choice of lighting unit/proximity/delivery

Good point. In our case, it really is a box room - there's little else but a double computer desk so the ceiling light is sufficient - there's no noticeable shadowing. Illuminated keyboards helped with the old light but while they're still handy with this new bulb there's not much need.

Coming from another (warm lit) room into the study at night the 4000K still feels a little cool, but you quickly adjust. What impressed me last night though was as the light outside was dimming we just turned on the study room and kept the curtains open.. and it was like time stood still - you know those mid-summer nights where it seems to stay light for ages? It was just like that for hours - it got darker outside but seemed like summer evening light in the room still.

so ,, what you're saying is... all your neighbours could see you through the window and you were perfectly lit, like on stage,...but you were oblivious to this and you couldn't see anything out through the reflective window and felt as though you were in total privacy in your sunlit room ;)


be cautious dear chap......

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Originally Posted by Zak33

so ,, what you're saying is... all your neighbours could see you through the window and you were perfectly lit, like on stage,...but you were oblivious to this and you couldn't see anything out through the reflective window and felt as though you were in total privacy in your sunlit room ;)

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I am an actor you know, darling ;)

But no - window is high, no line of sight to persons within save for eagles and drones.

thespian.....

Tubelight aka Fluorescent lights ?

https://www.amazon.co.uk/AURAGLOW-Su...low+cool+white

My solution, kalniel, was a set of LED bulbs that are dimmable, and have variable colour temp, by remote control. I do a fair bit of photo editing too, but find a warmer temp more comfortable most of the time. So I can set brightness according to what I'm doing, and want ambient levels at, and then cool the colour temp a bit to take the warm cast out for editing.

The remote can either be a little handheld unit or, if you buy a WiFi adapter, via an app on PC, phone etc.
The control also has four "groups", so you can put different bulbs in different groups and control on/off, brightness and colour temp for each group.

The bulbs are standard bayonet connectors, as I didn't want to change the light fitting or several angiepoise lamps, and each bulb is about the same output, when on full, as a 60w incandescent, so they're a direct replacement.

The snag? Cost, of course.

A bulb/remote pack is about £25, or bulbs are about £20 each. I got two bulb/remote packs so I have a spare remote, and several bulbs as well.

It works well, IMHO, is very convenient and I'm delighted. I can't detect any flicker from the LEDs, as I do with some CFLs.

I can't remember the supplier details but if you're interested I'll dig out the invoice and post them here.

Variable colour temperature? Now there's a thing!

Any idea if they do it through something like RGB or do they have groups of white emitters with different phosphors?

Personally I find around 5000K a nice bright white colour, but much above that gets a bit uncomfortable. For most stuff though, I find 3000k is nice.

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Originally Posted by Saracen

My solution, kalniel, was a set of LED bulbs that are dimmable, and have variable colour temp, by remote control. I do a fair bit of photo editing too, but find a warmer temp more comfortable most of the time. So I can set brightness according to what I'm doing, and want ambient levels at, and then cool the colour temp a bit to take the watm cast out for editing.

The remote can either be a little handheld unit or, if you buy a WiFi adapter, via an app on PC, phone etc.
The control also has four "groups", so you can put different bulbs in different groups and control on/off, brightness and colour temp for each group.

The bulbs are standard bayonet connectors, as I didn't want to chanfe the light fitting or several angiepoise lamps, and each bulb is about the same output, when on full, as a 60w incandescent, so they're a direct replacement.

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Thanks, yes I'd seen these were available now. Philips advertise similar. At the moment I'm really happy with the bulb I got as mentioned a few posts back, so much so that we're thinking of getting many for the rest of the house now! We'll keep warm ones for the bedrooms and lounge, but this 4K light will suit many other places.

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Originally Posted by kalniel

Thanks, yes I'd seen these were available now. Philips advertise similar. At the moment I'm really happy with the bulb I got as mentioned a few posts back, so much so that we're thinking of getting many for the rest of the house now! We'll keep warm ones for the bedrooms and lounge, but this 4K light will suit many other places.

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I kinda came in at the end of the thread with limited time, but I'll read through a bit later. I do also have some "cheap" bayonet-fit standard LED bulbs, that were about £10 for five, I.e. £2 oer bulb. They are available in warm and cool, but I only have warm, as the wife doesn't like "harsh" cool bulbs. I've got thise in most of the house, certainly in heavy use areas. I haven't changed all CFLs over mainly because I'm resistant to throwing away working CFLs (obviously) and once I take them out I'm never likely to put them back in.

Should we move house, the LEDs will be going with me and, by a strange coibcidence, the older slow-start CFLs may end up being left behind. ;)

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Originally Posted by watercooled

Variable colour temperature? Now there's a thing!

Any idea if they do it through something like RGB or do they have groups of white emitters with different phosphors?

Personally I find around 5000K a nice bright white colour, but much above that gets a bit uncomfortable. For most stuff though, I find 3000k is nice.

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I've seen variable colour too, you know, red, gree, blue etc but to me that seems .... gimmicky.

To be honest, I've wondered how they do it, but have no idea.

I'm not aware of LEDs that can vary light output. Last time is used them, they were on or off. On dimming, which is mainly why we first bought these (for the lounge) there seems to be about 10 discrete power levels, so I assume they do that throught switching banks on/off to control overall brightness. How they do the colour temp adlustment I've no idea.
The same metjod would work, but there must be a hell of a lot of indidual LEDs to do it that way.

The bulbs themselves look similar to conventional pearl incandescent bulbs, but with a bigger "base". They're sealed and opaque, and I'm not dissecting a £20 working bulb to see how they're made. :D

When one fails (hopefully not for a long time) I plan on an doing a bulbtopsy. on one. :D

Normal LED is blueish.

'Warm' LED is blueish with filter to block blue light.

Variable would presumably have one of both and you just vary the brightness ratio?

I've had a quick look online out of interest and the ones I found seem to do it by having one, or a set, of one colour temperature, say 2700k, and another of maybe 5000k, and mix the two, presumably by activating more LEDs or varying the power.

It is possible to vary LED power, either by current-limiting or PWM i.e. pulsing them on and off quickly, which is why PWM can appear as flicker if the frequency is too low.

Using normal triac dimmers is a bit more complex because LEDs themselves are non-linear WRT voltage and current, and in the case of designs fed by a switch mode power supply, chopping up the waveform with triacs will just make the SMPS unhappy and stop functioning after a point, before which the output will be constant anyway. I've not looked into it much but one way LED bulbs (as in retrofit BC/ES types) can be made dimmable is with some extra electronics to examine the waveform from the dimmer and pass the 'value' to the current limiter or PWM controller, and I assume using a big capacitor after the rectifier to smooth out the gaps in the supply voltage. It's one of those cases where it's a bit of a bodge to make them work in existing installations.

I've also just spotted a datasheet for an IC specifically designed for this purpose if anyone's interested: http://www.ti.com/lit/ds/symlink/lm3445.pdf

Edit: oops cross-post. @kalniel - all white LEDs (that I know of) consist of a blue LED with a phosphor to turn some of that blue light into other colours to make it white. Cool/warm LEDs just have different phosphors to vary the intensity of each part of the spectrum.

Just to add, the variable colour temp is not a simple jump from warm to cold. It's a graduated process. I haven't counted but I'd estimate 10 or 12 steps.

The reason I bought these in the first place was a problem with a conventional but old wall dimmer switch. Rather than mess about with that, I replaced it with a straight dual-gang on/off, and dim via the remote-dimmable LEDs. Though the bulbs were a bit pricey, I did save about £40 by not buying a new dimmer switch, and replaced 240w (60w x 4) of incandescrnts with these LEDs at about 32w (8-ish x 4).

Do you remember the make of those bulbs Saracen?

http://www.batterylogic.co.uk/lighti...nd-control.asp

It's the first three or so I'm talking about, that change colour temp, not the ones further down that change colour.

This is also the supplier I used, and have used for batteries and chargers for quite a while. My experience of them has been highly positive.

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Originally Posted by Saracen

http://www.batterylogic.co.uk/lighti...nd-control.asp

It's the first three or so I'm talking about, that change colour temp, not the ones further down that change colour.

This is also the supplier I used, and have used for batteries and chargers for quite a while. My experience of them has been highly positive.

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Thank you

I had no idea we had remote controlled led bulbs out there.. I'm peculiar if you use the app or the stand alone remote control? I'm more interested in using the app of course, since that would allow more people to adjust the led lighting freely and without searching for the remote control all the time, but the controller feels looks a bit fishy and I'm not really sure where power comes from and how reliable it is

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Originally Posted by Johna

I had no idea we had remote controlled led bulbs out there.. I'm peculiar if you use the app or the stand alone remote control? I'm more interested in using the app of course, since that would allow more people to adjust the led lighting freely and without searching for the remote control all the time, but the controller feels looks a bit fishy and I'm not really sure where power comes from and how reliable it is

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Power for the remote comes from a couple of AAA batteries. We've been using them for months, maybe a year, and yet to have any reliability problems. But I guess it's still early days.

As for physical remote versus app, I guess that's down to indivudual circumstances. For me, the app route isn't right. Neither the wife nor I have, or want, smartphones and I don't want to lug around, then power up, a 10" tablet in order to dim lights. ;)

Each remote does allow you to control four "groups" of bulbs, and every bulb can be controlled by multiple remotes. I keep a remote by my lounge chair, and can therefore switch up to four groups of bulbs, wuthoyt picking up the remote of even looking at it. It works for us.

We also don't want anyone else to be able to control the lights, but obviously, YMMV.

AAA are totally fine. For a second I got the impression there is some sort of external source, nvm. I've been thinking about adding some sort of dimmer lighting installation to my man cave, especially for my gaming mode for quite some time. One of my buddies is an electrician with **snipped out by moderator *** and every here and there I ask for advice about my silly ideas and the suggestion here was to go for a bit more complex lighting installation by adding extra led lighting along i.e. skirting or behind screens or flooring lighting & etc. Been browsing quite a lot recently and I'm seriously thinking if I should "get the best" and plan a grande lighting installation or simply grab dimmer bulbs and do something (way)simpler on my own. Would be great to have a "show your cave" thread but couldn't find one here