Dimmable CFL with >90 CRI?

[Drewster]

Howdy all,

I just found this forum, and I wish I'd found y'all before! I just recently replaced five R30 bulbs in my dining room with dimmable 2700K CFLs from GE, and man they suck. The light is very pallid, although I'm not sure what color to call it. I can say that food looks yucky.

Having read this forum a bit, I see that the CRI number can matter quite a bit. These have a CRI of 82, so now I'm wondering if there's any such thing as a dimmable CFL R30 with a CRI of 90 or above?

On the upside, it seems that Greenlite's SoCal hq is very near where I work, so I might drop them a line and see what they can do.

Thanks!

-Andrew

[lpcmidst128]

I always found warm/soft white to be suitable in the kitchen. Usually soft whites have a CRI of about 80. I've never seen any dimmable CFL R30s with a high CRI like 90+. Soft/warm white (~2700-3000K) seem to be the most common color temperature. Most of the high CRI lamps are usually labeled as daylight, natural, etc... with color temperature in the higher end of the spectrum 5000-6500K which makes it appear kind of blueish. The R30 shape + dimmable might be hard to find I'm not sure if it is available yet. So you might end up getting spiral CFLs. Most of the dimmable stuff is the soft/warm white. Try browsing through Home Depot, Lowes, Wal-Mart, and hardware stores to see if they have what you want. Yeah check out the Greenlite brand, I've had no problems with their CFLs, good price and good quality. Good luck.

I don't want to get too off topic but the GE Reveals do a good job in terms of the color. They make the R30 shape Reveal.

[2xTrinity]

Originally Posted by Drewster

Howdy all,

I just found this forum, and I wish I'd found y'all before! I just recently replaced five R30 bulbs in my dining room with dimmable 2700K CFLs from GE, and man they suck. The light is very pallid, although I'm not sure what color to call it. I can say that food looks yucky.

Having read this forum a bit, I see that the CRI number can matter quite a bit. These have a CRI of 82, so now I'm wondering if there's any such thing as a dimmable CFL R30 with a CRI of 90 or above?

One point worth noting is that CRI only applies to lights of the same color temperature. For example, a dim flashlight bulb running at 2600k will have the same CRI (100 by definition) as a high-powered halogen bulb at 3200k. The latter will render things more realistically though (more blue output).

A CRI that is lower than 100 tells you how much the color output deviates from a blackbody radiator (such as a hot wire) of that temperature, it does not tell you how the output is different though. For example, multiple CFLs with a rating of 82CRI can be very different from one another -- one brand might make certain colors look more vivid or brighter, while another will make things look duller or uglier. However, they both vary from true color by the same absolute amount, so the CRI number is the same.

I find that CFLs that are are 3000k or 3500k though actually look much better, even at the same CRI number. Sylvanias 3000k bulbs render thinsg much better than any 2700k CFL I've found. Also, 3500k bulbs (available from Sylvania, N:Vision, and possibly others) are my favorite CFLs yet. They are a similar color to filtered Incadescent bulbs (such as GE Reveal) and they render color much better than warm white CFLs, without looking out of place like Cool White or "Daylight" bulbs for retrofits.

In order to get the daylight bulbs to look good, you typically have to have very high brightness (similar to actual daylight) which makes it good for things like task lights, but not so much for dining room lighting in my opinion.

Finding those colors in a dimmable CFL may be difficult though, as they are (unfortunately) less popular. Right now we are still running incandescents on most of our dimmer circuits due to low availability of CFLs (and we've still cut our lighting cost by almost 2/3rds by replacing all non dimmable lights, which get more use)

If you do find it, you may find the cost is so much that it would actually be cheaper to switch to linear fluorescents with dimming ballast (and greater availability of high-CRI lamps).

[James S]

txTrinity has excellently summarized everything I have learned about using CF bulbs. Ignore CRI and look at color temperature. 2700k bulbs are good for dim applications. Higher temperature bulbs look terrible all by themselves, but given enough lamps and enough output in the room they will look much better at high levels than 2700k (warm) bulbs will.

For my higher output, multi light stuff my favorite are the sylvania 30 watt 3k, or 3100k bulbs. I have 8 of them in my kitchen can lights now and they are wonderful. For the lower output bulbs I prefer Phillips marathon bulbs and they really do last forever. The only one I've had go bad so far was the one that my daughter knocked the lamp off the table that it was in Personally I can't go higher than 3100 or 3500k except in the shop and over my workbench where I have lots of T8 tubes that give tons of light. High color temperatures in dim lights just look grey or bright blue, but get enough of it and it's great.

The phillips dimmable floods that HD has started carrying around here are pretty good. I have a couple and am happy with them. They are warmer than the 3100k bulbs that I prefer, but not too bad. And they have a much wider dimming range than most others I've played with.

Most important thing to remember is that as with all things you get what you pay for. Cheap CF bulbs are crappy and will not last and put out lousy light. If you spend a little money on them though they really will be quality light and last a long long time.

[brickbat]

Originally Posted by Drewster

...The light is very pallid...

Pallid, Hmm.

One thing about dimmable fluorescent lamps is that their color temperature behaves exactly unlike a dimming incandescent. Incandescents shift from yellowish-white at full power toward increasingly yellow, then orange, and then red as they are dimmed. Fluorescents do not shift color nearly as much. I have read (but not observed myself) that the shift is reversed, so as they are dimmed they shift away from yellow-white toward bluish white.

So, while incandescents get more colorful (yellow orange) as they are dimmed, fluorescents do not - they remain as colorless as they were at full brightness. Pallid by comparison to the golden yellow goodness of a dimmed incandescent.

Details from they guys that really know here:

http://groups.google.com/group/sci.e...f8be2f6ddab927

I don't think you'll find a 90 CRI compact fluorescent in a 2700, 3000, 3500, or 4100K lamp.

If you desire fluorescents that look like incandescent lamps, try another brand of 2700K lamps. Lamps from different manufacturers, even though they have identical specs do have a different appearance. The closest I've seen (to an incandescent look) are the Home Depot house brand called 'Commercial Electric'. They have since been replaced with another different brand, but I have a hunch the product is the same. But they still won't have the shift toward red as they are dimmed.

[2xTrinity]

If you desire fluorescents that look like incandescent lamps, try another brand of 2700K lamps. Lamps from different manufacturers, even though they have identical specs do have a different appearance. The closest I've seen (to an incandescent look) are the Home Depot house brand called 'Commercial Electric'. They have since been replaced with another different brand, but I have a hunch the product is the same. But they still won't have the shift toward red as they are dimmed.

Home Depot's current brand is called N:Vision is simply the renamed Commercial Electric brand. I would agree that their 2700k is the best I've found in that color temperature. Their 3500k is probably my favorite overall

I have read (but not observed myself) that the shift is reversed, so as they are dimmed they shift away from yellow-white toward bluish white.

I actually notice this effect in some of my outdoor CFLs when they are started cold. I believe the situation here is that the phosphor needs to be within a certain temperature range to operate properly. This is the reason why the CFLs designed for use in recessed fixtures have a different composition which runs better at a higher temperature -- as a consequence, they take a minute to warm up to full brightness. When the phosphor is too cold (or too hot, as in the case of putting a regular CFL in a recessed fixture) to operate properly, the CFL's light output will be coming only from the arc across the fill gases, which produces harsher tones.

[James S]

Home Depot's current brand is called N:Vision is simply the renamed Commercial Electric brand.

I used to have a lot of these "commercial electric" brand. However I also use a lot of X10 and other powerline signaling devices around here. (My job of the last few years has been writing home automation and security software that turns on and off your lights among other things) and they used cheap or bad capacitors in a lot of those ballasts. If you use anything that communicates over the powerline, those phone line extenders, internet, X10, UPB, Insteon whatever, watch out because the filter caps on them go bad silently, the light keeps working fine. And then they flood the powerlines with noise that totally stops any signaling and potentially affects other things too. It's very difficult to debug since the light is still working fine while it's dumping garbage onto the lines.

Mostly they failed in base up or horizontal installs. I still have several in left in regular lamps that haven't had problems for years and years, but all of them that were in base up have done the silent failure thing. So I think the caps just weren't rated for the temperature.

This does not apply to the commercial electric floods, I have lots of these in the house too and for 3 years of running 15 of them every night for hours and hours they are all still working perfectly. I'm very happy with the flood lights.

[Sparce]

Drewster - CRI is an antiquated measuring mechanism. Its supposed to measure how close in color an object looks as compared to when lit by the sun. It was originally created to measure incandescent color rendering (CR). I took a lighting class from Philips Lighting and I learned that CRI is relative to the family of light bulbs. So an 82 CRI FLU lamp with color temp 2700 does not produce the same visual color perception as a similar 82 CRI FLU with color temp of 4000. In my opinion, CRI is useless and misleading.

I find color temperature more useful as it tells me if the light produced is more Yellow or more Blue. Yellow light radiates at color temps in the low #'s. As the color temp increases, light tends to gets more Blue. Now, too much Blue sucks as it makes things look dead, and too much Yellow light sucks as it washes out much of the cool colors. I can't say what is the best as, as i learned in the class, it is base on personal preference and personal perception of what True red, green, blue and yellow is. But, for my taste, I like FLU at about 4000 Kelvin color temperature.

Additionally, the class taught how different materials in a house will affect the light due to reflection. It showed how having a dark carpet will absorb more of the light, making the room a bit duller. Having the same lamp in a room with floor tiles, could produce a much brighter setting. So you need to adjust your lighting according to the room you are lighting.

Conclusion, a 90CRI FLU is not necessarily the answer as you are still missing color temperature. My company paid for the lighting class, so I can not say how expensive it is, but if you have a chance, I would suggest taking it, or a similar class. It is really interesting! In case you are interested, or anyone else on the forum, my class was called somthing like "Introduction to Lighting" and I took it in Somerset, NJ.

Regards

[dudeldam]

Try Osram Interna 2700K. Although the colour rendering index is NOT >90 and the dimmability is NOT given, they provide in my eyes the best possible "incandescent illusion". In our living room there´s a lamp with 5 bulbs, which are switched in groups of 2 and 3 by a two-step switch. I used incandescent opale globe bulbs for the smaller and compact fluorescent globes (23 Watt Osram) for the biogger group. It is hard to tell the difference after 3 Minutes warm-up time.

[pedalinbob]

I believe we have that same lamp (does it have multi-colored lamp shades?), and I didn't place fluorescents because the rapid switching might kill them.

Our lamp switches 2 on, then 3 others on (while turning the first 2 off), then I believe all 5 on.

I am tempted to rewire it so that is switches 2 on, adds a third, then adds the last 2. It might help save the ballasts, allowing me to use fluoros.
But, your idea of using the fluoros in the 3 which are turned on in the second step is a very good idea, because we use that setting (or all 5) the most.