LED light bulbs - some questions before buying
- Thread starter avole
- Start date
Tony L
Administrator
This is certainly the case, but there are still clearly other factors, e.g. one BBC Micro might be an ugly bright yellow-brown, another from the same factory and manufacturing time-frame will have retained it’s original cream colour and look almost as new. It is very hard in hindsight to figure out what environmental factors accelerated the former. UV exposure is suspected, as is fluorescent lighting, as is heat, but it is hard to be precise, or to ascertain if modern LED lighting may prove kinder to these plastics than either the fluorescent or incandescent of their eras. It is the latter point I’d like to understand.
Miniscule amounts of UV from fluorescents, probably (far) less from white LEDs (none from LEDs that are mixed red, green, blue rather than fluorescent), essentially none from incandescent of any kind.
Sit some ABS by a window in full sun and it will gently cook during good UK weather, substatially accelerating any diffusion, plus, add the effects of the tiny amount of UV.
Sit some ABS by a window in full sun and it will gently cook during good UK weather, substatially accelerating any diffusion, plus, add the effects of the tiny amount of UV.
k90tour
pfm Member
Actually, CRI Ra (colour rendering index) is a very limited tool as it is usually represented. It only uses 8 pastel colour charts and LEDs are able to achieve decent results. There is a more exacting CRI Re index that uses 15 colours, including red and pink. Very few LED products score above 90 on this as they are poor on reds. Which is where incandescent really scores as it is full of longer wavelengths. If you want the performance of halogen or incandescent, ask about R9 values within the CRI Re reports.
Thanks for all the comprehensive information from all 
In the end I went for the mid-priced Auchan house brand LEDS, which have a 5 year warranty. The boxes give details, although I'm not sure how much they latch the information given above:
40W
470 Lumen
2700K (Described as Warm)
My main concern is whether they'll affect my Thai herbs which have just started to poke nervous heads above the earth in their flowerpots, but it may be more the extended time of relatively bright light that may affect them. No dimmers here, only some remotes to cut power to various gadgets.
Also bought an infrared heater on special. There are mixed reports about them in the various web reviews, so will see - flat panel looks good, though, I have to say.
In the end I went for the mid-priced Auchan house brand LEDS, which have a 5 year warranty. The boxes give details, although I'm not sure how much they latch the information given above:
40W
470 Lumen
2700K (Described as Warm)
My main concern is whether they'll affect my Thai herbs which have just started to poke nervous heads above the earth in their flowerpots, but it may be more the extended time of relatively bright light that may affect them. No dimmers here, only some remotes to cut power to various gadgets.
Also bought an infrared heater on special. There are mixed reports about them in the various web reviews, so will see - flat panel looks good, though, I have to say.
2700K is very yellow-orange and I find it very relaxing - it is what I use for many lamps here.
Plant growth i driven by red-orange, but the inter-nodal distance is dictated by the amount of blue. So, your seedlings will grow well, but VERY leggy as they'll have no blue worthy of the name in all probability.
"Daylight" is a total misnomer and all but meaningless. Just stick to CCT.
Plant growth i driven by red-orange, but the inter-nodal distance is dictated by the amount of blue. So, your seedlings will grow well, but VERY leggy as they'll have no blue worthy of the name in all probability.
"Daylight" is a total misnomer and all but meaningless. Just stick to CCT.
awkwardbydesign
Officially Awesome
Well yes, but then I have never used fluorescent lighting. I have even taken my own incandescent lighting into work. Fluoros make me blink and twitch.
PS: Maths, you're not American!
Maybe so, but the lighting industry only routinely uses Ra.
I can't be bothered trawling to find details, but the comment about Ra being derived from only 8 pastel colours is likely nonsense in the real world, not least because "pastel" has no meaning in the physics of light.
I worked in lamp R&D for GE USA and we used a spreadsheet to calculate Ra and that split the visible spectrum into very many small wavelength bands. The illustration also includes no primary colours, which is also likely nonsense. I have long ago lost the speadsheet, otherwise I could refer to that for the real calculations involved in Ra calculation, or indeed, drag out the text books that are here somewhere.
Arkless Electronics
Trade: Amp design and repairs.
So what the hell is going on with BC (bayonet cap) light bulbs? It was always very rare to find a main ceiling light bulb that was anything else in the UK but when I look at the lightbulb section in local supermarkets I now can't find any at all! It's looking like I'll have to change the sockets in several of my light fittings next time a new bulb is needed.... and yet I have never seen or heard any mention of BC being phased out...
Sue Pertwee-Tyr
Accuphase all the way down
My local supermarket is now fairly useless for lightbulbs. I’m inclined to get them online these days. Don’t Farnell or RS do bulk packs? I’m sure you have accounts with them.
Arkless Electronics
Trade: Amp design and repairs.
I've never looked. It just seems very odd that what was pretty much the standard fitting for UK use seems to have been phased out without my hearing anything about it... I would have expected to hear people talking about having to get a sparky in to change all their light sockets.. but never have heard this... and yet can'y find a single BC fitting bulb in any supermarket.
clivem2
pfm Member
My supermarkets have BC bulbs but I agree they are harder to find. I also find the range on offer is somewhat narrower than screw-fit bulbs. I put this down to so many lamps being imported and so are to a Euro standard, not UK. Maybe a side effect of Brexit-21 is that we'll start making our own lamps again.
Arkless Electronics
Trade: Amp design and repairs.
Indeed my guess was that ES and MES are standard around the world and most bulbs are imported...
CFL bulbs are also unobtainable in my local supermarkets and again I heard nothing about this beforehand.
For at least two years now my local Morrisons and Lidl have had only ES and MES LED bulbs... in loads of sizes and shapes and "warm light" options but not a single item to fit a normal UK ceiling pendent light BC socket.
In my workshop I have a row of bulbs dangling from a foot of bamboo with wires soldered to them then paralleled together and connected to a male bayonet fitting... needs must.
I'll have to try and remember to buy some BC bulbs next time I'm in a large B & Q or Asda superstore etc!
Barrymagrec
pfm Member
The problem is not the bulbs, it`s the fittings, now almost all light fittings are imported they are almost all ES. That`s why BC bulbs are becoming rare.
As in so many other ways now, we are screwed.
As in so many other ways now, we are screwed.
clivem2
pfm Member
Yes, screwed indeed!
A point of clarity to illuminate my post above - when I used the word lamp I was meaning the whole lamp / light fitting / eg table-top lamp...not only the bulb.
gavreid
Pretty Words...
You can also buy BC to ES adaptors should you wish...
https://www.amazon.co.uk/dp/B07P8QJTMM/?tag=pinkfishmedia-21
https://www.amazon.co.uk/dp/B07P8QJTMM/?tag=pinkfishmedia-21
This site contains affiliate links for which pink fish media may be compensated.
