SWMBO'd wants a good, bright, daylight quality, light source for doing needlework. This is to fit into a magnifier angle poise type lamp with E27 base with not much more space than a normal GLS takes.
I've pointed her at seeing how the bog standard CFL's we have or a
3000 K LED stand up. She couldn't really detect any difference in the colour rendering(*), light level was the main complaint, not enough. I was thinking the best bet would be one of those "daylight" (aka blue tinted) 60 W tungsten GLS bulbs but she has found:
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Reasonable level but are the claims about colour likely to be accurate? I'm not sure what the "Finish 865 - Daylight" means in the spec list. Is that related to the three digit number that has something to do with colour temp and/or CRI?
(*) They look very different through a basic spectroscope. The LED is amorphous from red to green a small gap then a blue/purple band. The CFLs have 4 distinct bands red orange green purple.
I attempted to use a 30W version of same and found it to be headache inducingly blue, replaced it with a 25W 2700K version and found it far more acceptable, didn't seem that 'warm' but I hear what you say about colour rendering.
Here's the 30W one I sourced (same mfr):
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Markedly cheaper than your example but sadly they're not doing 20W in ES at the mo.
I notice a lot of companies selling to those with sight problems sell task lights it might be interesting to look at some. R NIB have some but there are others about. Brian
"Daylight" has a whole swathe of different properties which she might be after, including the sweeping property of being different from whatever artificial light happens to be in use at the moment.
That's going to be a challenge.
Can the fitting take an R80 spot/flood lamp (and is the lamp orientated to emit light from the end or the side of the bulb)? (The magnifier angle poise I'm familiar with uses a circular fluorescent, but they aren't very bright.)
The 23W GE Genura is the only CFL which is similar size to the 100W R80 reflector lamp it replaces, and generates slightly more light output than a 100W R80. It comes in 3000k and 3500k. It's damn expensive though. It's the only viable CFL reflector lamp, as the spiral/folded tube types perform poorly unless the reflector is many times the size of the tube. This is where LEDs can win out.
GLS LEDs are up to around 75W equivalent, but mostly emit light in all directions. There are Chinese manufacturers who are producing products with more directed light, e.g to one side or even crown silver replacements, but you have to search these out from importers. LED lights are not always pleasent to work near, due to their intense point sources - if it's ever in your field of view, look for one with a diffuser.
865 means colour rendering of between 80 and 89 (usually nearer
80), and a colour temperature of 6500k, which is a blue-white, which won't render red colours very well unless you get the light level up to midday sun levels (ie. using loads of the lamps).
It may be a little brighter than a 3000K CFL of the same power rating, but not by a large amount.
I would avoid going above 4000K.
LEDs are pure blue, and use phosphors to generate the other colours. Fluorescents are mostly UV, with usually 3 phosphor colours to generate proportions of red, green, and blue. The purple comes from several weaker visible mercury lines in the discharge. Specialist higher colour rendering tubes (CRI >= 90) usually use more phosphors to fill in more of the spectrum, but are more expensive and very hard to find.
In my electronics work area where I also want lots of light, I have a twin 5' fluorescent fitting with highly polished reflector, hanging 3' above the work surface (and I occasionally bang my head on it;-). It's a bog-standard office fitting with electronic control gear.
I found them generally poor. Parents had a pair of spotlights, a bit like crown silver spots except the crown was part of the fitting so they took standard clear GLS. The only CFLs which fitted were some prolites, but life was very short. Eventually, we ended up with a couple in there which lasted ~3 years (until recently decommissioned), but most only lasted a few months. CPC stopped doing them.
Certainly for the higher power CFL's, think I'll give them a miss.
Side of a normal GLS bulb, similar to this but up to 60 W:
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So reflectors are out. It does appear to more of level thing than "daylight". Might see if I can get a 100 W equivalent "GLS" halogen, that ought to be about 60 W in reality but I bet I get complaints about the heat...
LED ought to be able to fit the space available but getting the required light level is probably still a challange for them.
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