GE sunshine 5000K CFL

[Bright+]

Taken with an ordinary camera with white balance manually set to white box surface under DSGN 50 color matching lamp, then took pics of same items with same ISO & shutter speed.

WHITE BALANCE SET REFERENCE:
CIE coordinates 0.345,0.359

0.346, 0.356

0.344,0.355

The light source doesn't really matter when it's looked at, but how the object looks after the light is reflected matters. After all, the pictures you're looking at the CCFL or LEDs filtered through the LCD on your monitor.

 

[blasterman]

What's a "Macbeth tube"? Can you post the specs and SPD?

Why not buy one Gretag-MacBeth tubes test it yourself? It's the only tube on the market I'm aware of worth the effort in light boxes. None of the other tubes you mention were advised by us via Kodak nor X-rite's engineering depts for critical color matching. Good for over the floor at 'The Gap' and J.C. Penny's though. Spend a few hundred hours looking at 8x10 trannies and you start to get fussy with tubes.

The usefulness of CRI is debated. The Ra8 system only concerns how well it renders standard eight colors.

Which is why MacBeth charts are so pointless for this. Also, MacBeth charts were rather useless for film use as exhibited by the fact that chemical based mini-labs in the past never gave you prints with consistent color balances, but were capable of printing consistent 8-point patches. A MacBeth chart is a compressed (low gamut) 2-D splice of a 3-D matrix, and given the terrible non-linearity of color film to begin with it was futile. The only reason Macbeth charts are used to compare digital sensors is because unlike film, digital sensors are highly linear to begin with.

If its just about spec numbers, the Philips 950 lamps are rated CRI 98

Sir, you can rave about the Philips all you want, but it's not that high, and the 98 spec is an 'Advertised' spec. The high CRI phosphor mixes used in similiar tier bulbs are all fairly close due to manufacturing reasons. Nobody drops a 98 CRI phosphor mix in a tube and sells it at the same price. Westinghouse and Philips both make a higher CRI / lower Lux tube, but it's not 98 CRI by the same standards everybody else is playing with.

Also, if the Philips is 98 CRI' then a cool-white Cree is 85 and a Solux 100 by that measured standard. If the Philips is indeed a '98' CRI bulb, why is it's color rendition inferiour to a 98 CRI Solux? If the sun is 100 CRI, and the Philips is 98, then I have to conclude you don't get outdoors much.

This claim by Philips is yet another example of why the current CRI
standard is out-dated and manipulated by manufactuers. Fluorescent tubes for example are almost entirely devoid of red beyond the same peaks as most LEDs, but tubes like the Philips are given a 98' CRI mark?

Continuous spectrum lamps have broad emission spectrum including ranges our eyes are not very sensitive to,

Such as? Do explain what Spectrum between 450nm and 650nm our eyes aren't sensitive to.

The difference between cont. and multi-phosphor lamps is that multi-phosphor lamp is designed to focus their output to primary colors

Define 'primary color', and tell me where the vote took place to declare what a 'primary color' was? MacBeth has their standard, Pantone has theirs...Sony has another. The 'primary colors' used in fluorescent lamps are the specific phosphor peaks used by that industry. Filling in the gaps to better include CRI plots might be your definition of 'continuous spectrum', but it's not mine.

Again, unlike a high CRI incan source like a Solux which filters out the remaining bands, your 98 CRI Philips still has the same peaks as it's cheaper cousins, just not as pronounced or in as spatialy distributed bands to get peak perceptual lumens. However, if you're working with a color that happens to be sitting near one of those peaks, CRI drops off dramatically.

There is no such thing as a continuous spectrum fluorescent. They all have significant peaks which are ignored for marketing reasons. Yes, there has been significant leveling with better multi-phosphor technology, but the spikes are still there.

The Sunshine CFL is Energy Star rated. If it was to be made using Chroma 50 phosphor, it will not meet the efficiency requirement to get the stamp.

Just for the sake of arguement, I've ran into several sites claiming the Chroma 50 is the same phosphor as the CFL Sunshine. I personally don't care, but unless you personally work for GE why should I take your word over theirs? Also, the Energy Star cert is not applied evenly, but only on specific bulbs and appliances submitted for approval.

This is the 5000K CRI 98 Philips 950

This your personal test? Again, spectral graphs I googled for the Philips look nothing like the chart you displayed and sure as heck don't show much spectral energy beyond orange-red. However, your chart shows pretty strong spectral energy beyond 650nm, which is next to impossible. Matter of fact, the spectral graph you displayed for the Philips looks suspiciously like it was taken with a PAR weighted meter because of the double humps.

This may seem like I'm picking on the Philips, but only in the sense it's trying to market it's way from the rest of the pack when the tubes are likely made in the same plant in China alongside GE and Westinghouse tubes in the target tier.

 

[Bright+]

Why not buy one Gretag-MacBeth tubes test it yourself? It's the only tube on the market I'm aware of worth the effort in light boxes. None of the other tubes you mention were advised by us via Kodak nor X-rite's engineering depts for critical color matching. Good for over the floor at 'The Gap' and J.C. Penny's though. Spend a few hundred hours looking at 8x10 trannies and you start to get fussy with tubes.

Enough of subjective whiff. Give me data. Why am I not surprised Macbeth (now X-rite) recommended their own products instead of competitor?
You must be expecting I have access to spectrophotometer to capture the SPD and calculate CRI.

Do you know that car manufacturers only recommend OEM parts too?

it's not 98 CRI by the same standards everybody else is playing with.

First you say it needs to be 95 or better, then say the Philips 950 is not the same game. It is rated 98 Ra8. What game is "everybody else" playing in?

Also, if the Philips is 98 CRI' then a cool-white Cree is 85 and a Solux 100 by that measured standard. If the Philips is indeed a '98' CRI bulb, why is it's color rendition inferiour to a 98 CRI Solux? If the sun is 100 CRI, and the Philips is 98, then I have to conclude you don't get outdoors much.

Regular incandescent, candlelight and sunlight are all CRI 100. Give me an objective definition of "inferior" that can be shown without personal judgment.

Such as? Do explain what Spectrum between 450nm and 650nm our eyes aren't sensitive to.

Look in the IESNA handbook. triphosphor lamps improve lumens per watt by focusing on ranges of spectrum where our eyes have higher sensitivity. I didn't imply we're completely blind to 450-650nm.

Just for the sake of arguement, I've ran into several sites claiming the Chroma 50 is the same phosphor as the CFL Sunshine. I personally don't care, but unless you personally work for GE why should I take your word over theirs? Also, the Energy Star cert is not applied evenly, but only on specific bulbs and appliances submitted for approval.

Product # 71765, CFL Sunshine, CRI = 82. 64 lumens per watt (by math)
http://www.gelighting.com/na/busine...lasts_Section_5_Compact_Fluorescent_Lamps.pdf

Specs show that it's not the same phosphor as Chroma 50. Efficacy is even lower at 55 lumens per watt on F40T12/C50 and CRI is 90.

This your personal test? Again, spectral graphs I googled for the Philips look nothing like the chart you displayed and sure as heck don't show much spectral energy beyond orange-red. However, your chart shows pretty strong spectral energy beyond 650nm, which is next to impossible. Matter of fact, the spectral graph you displayed for the Philips looks suspiciously like it was taken with a PAR weighted meter because of the double humps.

No, it's from Philips datasheet.
http://www.prismaecat.lighting.phil...3d-419a-b979-a33fbd9cfe5f/F32T8_TL950_1SL.pdf

This may seem like I'm picking on the Philips, but only in the sense it's trying to market it's way from the rest of the pack when the tubes are likely made in the same plant in China alongside GE and Westinghouse tubes in the target tier.

You really have no idea what you're talking about. The Colortone 50/75 phosphors are similar to Chroma 50/75 and Design 50, but the Philips 950 phosphor isn't offered by anyone else, thus far. The TL950 is made in Holland. Please explain where you came to your conclusion they're made in China.

Don't post reference URLs or anything...

 

[Random Guy]

...This may seem like I'm picking on the Philips, but only in the sense it's trying to market it's way from the rest of the pack when the tubes are likely made in the same plant in China alongside GE and Westinghouse tubes in the target tier.

GE makes most of their non-specialty T8s in Canada. If I remember correctly, they make most of their oddball ones in Hungary, because they own Tungsram, which has a plant there. Philips makes their T8s in the US, and I believe that Sylvania also makes their T8s here.

 

[UnknownVT]

Recently my kitchen under the counter F20 T12 fluorescent tube went, and I had to get a replacement.

Instead of just replacing with the same "Kitchen & Bath" 3000K tube -
because I liked the Sunshine 5000K CFL so much -
I thought I'd try the GE Sunshine 20 5000K F20 T12.

When the 5000K first came on I thought this seemed a bit more blue - but then that's most probably because my main kitchen lighting is a 13 watt 2700K Soft White CFL - and that is usually already on, so my eyes would have adapted to that color/tint.

The next observation was that the tube seemed dimmer than the old 3000K tube - and I was kind of "shocked" that the specs of this new Sunshine 5000K tube was 875 initial lumens (mean = 790 lumens) - this is about the same as the 13 watt 5000K Sunshine CFL! Whereas the same sized "Kitchen & Bath" 3000K tube was rated 1275 lumens (mean = 1200 lumens)

So where have all the lumens gone?

Well a bit more "research" the 5000K Sunshine tube CRI=90!
This is higher than the 5000K Sunshine CFL version (CRI=82),
Kitchen & Bath 3000K tube CRI=70
and I tried for a couple of days the GE 4100K "Cool White" tube and that CRI=60!!

So it would seem that there is lumens efficiency loss due to achieving the higher CRI?

Looking more closely and I find the tube is actually marked Chroma 50:

To be honest so far I think I prefer my GE 5000K Sunshine CFL -
but it is early days yet - the higher CRI=90 of the F20 T12 5000K tube may make a difference - but so far I haven't seen it yet.....

 

[Bright+]

Look at a normal GE Reveal light bulb illuminated by these sources.

It will have the pinkish hue that is present in true daylight under Chroma 50. Under CFL Sunshine(which is actually SPX50), it will look pale blue with no hint of pink under triphosphor CFL.

The SPX50 and F32T8 Sunshine are tri-chromatic rare earth fluorescent lamps.

The T12 Sunshine lamps are Chroma 50, a wide spectrum phoshpor. It also has low persistence, so the 120Hz strobing will be worse than normal lamps. Its highly advisable to use it with electronic ballast. Chroma 50 is used where meeting ANSI D50 standard is expected.

There was a 1,350 lumen 5,000K/85 CRI in F20T12 by Philips, but its no longer being made, so you'll have to find it online from someone who has it in stock.
It's F40T12/50U. They also have a F40T12/C50 (Colortone 50) which is the Philips equivalent of Chroma 50, but this one is also low efficiency.

Tri-chromatic fluorescent lamps are specifically tuned for high lumens per watt and they're not as good for correct color rendition.

 

[hank]

More spectra:
http://ledmuseum.candlepower.us/led/spectra7.htm

Do you have a spectrometer, or were those from published info?

 

[UnknownVT]

The T12 Sunshine lamps are Chroma 50, a wide spectrum phoshpor. It also has low persistence, so the 120Hz strobing will be worse than normal lamps. Its highly advisable to use it with electronic ballast. Chroma 50 is used where meeting ANSI D50 standard is expected.

Tri-chromatic fluorescent lamps are specifically tuned for high lumens per watt and they're not as good for correct color rendition.

Many thanks for that info.

I did notice the strobing on the tube - but just put it down to it being linear and the less noticeable strobing of the CFL being a spiral/coil

In "theory" CRI of the same CCT within 5 points are supposed to be almost indistinguishable (see GE page on CRI ) ...

Having said that I still seem to prefer the GE 5000K Sunshine CFL despite it being CRI=82 vs. CRI=90 of the 5000K Sunshine F20/T12 tube (so maybe 8 points CRI isn't that much?)

It may well be the where they are installed and the contrast when I first turn on the tube in the kitchen since I usually already have a 2700K CFL on.

Although I obviously have tried turning on the tube only without any other lights on first - during both night and daytime when there was daylight coming through the window.

I have also replaced the 2700K soft White CFL with the 5000K Sunshine CFL in the kitchen - but even though the lights look about the same - somehow I still seem to persist in liking the CFL more -

I know it doesn't seem to make sense, and seems emotionally based - but somehow that still seems valid to me - even if I appear quite silly trying to explain this.

I think there may be something in our make up that favors sunlight (association with sunny days?) - whenever I turn on the 5000K Sunshine CFL it makes me smile.... whereas with the 5000K F20/T12 tube of CRI=90 - it's almost like I initially try to convince myself that it may not have the tiny bit too much blue.... then when I get used to it, it does seem just fine and as good as the CFL.

Is there any good reason I feel this way?
Or should I just consult a shrink?

 

[jtr1962]

Just a thought here but I honestly think the primary reason you're liking the higher CRI tube less than the CFL is exactly because it flickers. Even if you don't notice it by eye, the flicker just "feels" wrong. I noticed the difference immediately whenever I changed out a magnetic ballest in one of our tube fixtures for an electronic one. Even though the tube was exactly the same, the light quality felt better. If you can find a retrofit electronic ballast to run your tube fixture I might suggest trying it.

Incidentally, I noticed how much better subway stations here feel when they replaced the old tube fixtures ( 6 foot T12s ) with 4 foot T8s. Even though flicker wasn't perceptible consciously before, its absence is noticeable. Incidentally, the T12s used before weren't cool whites with poor CRI. They were Sylvania Designer 3500 IIRC, so it's not like the improvement is because they replaced tubes with crappy CRI with better ones. Rather, it's the lack of flicker making the difference. Also, the lighting levels are a bit higher. Don't even ask how lousy the stations looked back when they were lit with incandescent bulbs in the 1960s or early 1970s. They were dim and cavernous and orange, totally uninviting ( except for muggers ).

 

[UnknownVT]

Just a thought here but I honestly think the primary reason you're liking the higher CRI tube less than the CFL is exactly because it flickers. Even if you don't notice it by eye, the flicker just "feels" wrong. I noticed the difference immediately whenever I changed out a magnetic ballest in one of our tube fixtures for an electronic one. Even though the tube was exactly the same, the light quality felt better. If you can find a retrofit electronic ballast to run your tube fixture I might suggest trying it.

Many thanks for that very useful input.
I never realized that a ballast could make a difference in flickering.

Any recommend an economical electronic ballast suitable for this GE F20/T12 5000K Sunshine tube please?

In the meantime FWIW I took a pic of my Macbeth under this GE F20/T12 5000K Sunshine tube (CRI=90)

There's "problem with the F20/T12 shot since it is a fixed in place under my kitchen counter - I had to place the Macbeth the best I could "in situ" - as can be seen the bottom of the chart was less illuminated to the top (see the top and bottom borders).

This is kind of unfortunate as I normally compare the bottom row of gray patches to look for any tint variations compared to my daylight reference. Since the bottom row is less well lit it is darker and seems a bit warmer.

Undaunted and stubborn - I took the same shot into my editor and upped the brightness/contrast to best match by eye the daylight control shot - but with NO color or tint adjustments -

although the luminance level seem about the same this F20/T12 seems a bit warmer than any of the others in this comparison (look in particular at the second and third patches from the left). This contradicts what I thought I saw by eye where I had an initial feeling the tube was a tiny bit bluer than the CFL version.

Of course the top row also causes some "problems" since it is a bit brighter therefore paler than the rest of the chart due to the uneven illumination. Have to take my word for it that it is pretty similar to the daylight and CFL versions....

No, don't take my word for it.
I took the shot into my editor and adjusted brightness/contrast only to try to get it as close to the top row of the daylight shot:

 

[jtr1962]

Many thanks for that very useful input.
I never realized that a ballast could make a difference in flickering.

Any recommend an economical electronic ballast suitable for this GE F20/T12 5000K Sunshine tube please?

F20/T12 electronic ballasts are fairly hard to come by, but I found this one. It might be a bit too pricey though ( it is for me anyway ). An alternative if you're handy is to take apart a burnt-out CFL. 9 times out of 10, the tube is burnt out but the ballast works just fine. Note where the ballast is connected to the tube, remove the ballast, and install it in your F20/T12 fixture. A 20 or 26 watt CFL ballast seems to work reasonably well with F20/T12 tubes. Of course, I'll put in the usual disclaimer about being careful working with high voltages, and also possible fires.

Home Depot might have something also, although they generally don't list all of their available ballasts on their website.

Undaunted and stubborn - I took the same shot into my editor and upped the brightness/contrast to best match by eye the daylight control shot - but with NO color or tint adjustments -

although the luminance level seem about the same this F20/T12 seems a bit warmer than any of the others in this comparison (look in particular at the second and third patches from the left). This contradicts what I thought I saw by eye where I had an initial feeling the tube was a tiny bit bluer than the CFL version.

That actually matches my impression of the GE Chroma 50. It initially seems somewhat blue, but compared to other 5000K tubes side-by-side it's actually a bit yellower.

Of course the top row also causes some "problems" since it is a bit brighter therefore paler than the rest of the chart due to the uneven illumination. Have to take my word for it that it is pretty similar to the daylight and CFL versions....

Same as my observations also-not a whole lot of difference between most 5000K flourescents. The Chroma 50 appears to render deep reds a little better than triphosphor or even pentaphosphor ( Maxum 5000 ) tubes, but other than that they all look pretty much the same.

 

[Bright+]

Many thanks for that info.

In "theory" CRI of the same CCT within 5 points are supposed to be almost indistinguishable (see GE page on CRI ) ...

The CRI is a measure of calculated color distortion of eight reference colors. Another more technical term for CRI is called Ra8, with the eight pointing to the use of eight reference colors.

There are some materials that exhibit metamerism. Substances, especially minerals with very specific spectral absorption properties will look different depending on spectral contents of illumination.

It's possible for something to have two objects to look the same under one lighting, then another under a different source.

Neodymium glass is something with a very narrow spectral absorption properties. It has a hint of red and can look slightly ruby red under natural light or wide spectrum light like Chroma 50 (CRI rated 90).

An SPX50 lamp may have a CRI of 85, but the spectral contents is far different and any hint of red will go away.

Notice the blue transparent plastic and tinted glass doesn't change color, but neodymium glass shows drastic color change between Chroma 50 vs SPX50. There are art work made of neodymium glass and the appearance is different enough to make them look like they're two different things.

Wide spectrum/Chroma 50 (CRI 90), or under sunlight

Triphosphor (CRI 85, SPX50)

On the left is the spectrum of Chroma 50, and on the right is SPX50. You can see the distinct breaks in triphosphor lamp and absence of yellow and cyan light. The Chroma 50 has a pronounced line in green that didn't turn out in photo. This is one of mercury emission lines.

 

[UnknownVT]

That actually matches my impression of the GE Chroma 50. It initially seems somewhat blue, but compared to other 5000K tubes side-by-side it's actually a bit yellower.

Same as my observations also-not a whole lot of difference between most 5000K flourescents. The Chroma 50 appears to render deep reds a little better than triphosphor or even pentaphosphor ( Maxum 5000 ) tubes, but other than that they all look pretty much the same.

Thanks for the corroboration on my observations and the advice on electronic ballasts -

I took a quick look for electronic ballasts and yes they seem expensive -
I did find some lower priced ones:

Fulham Sugar Cube SC-120-120-CT12
Fulham PONY SC-120-120-CT12
Halco ProLume 50108 One Lamp

Notice the blue transparent plastic and tinted glass doesn't change color, but neodymium glass shows drastic color change between Chroma 50 vs SPX50. There are art work made of neodymium glass and the appearance is different enough to make them look like they're two different things.

Wide spectrum/Chroma 50 (CRI 90), or under sunlight

Triphosphor (CRI 85, SPX50)

On the left is the spectrum of Chroma 50, and on the right is SPX50. You can see the distinct breaks in triphosphor lamp and absence of yellow and cyan light. The Chroma 50 has a pronounced line in green that didn't turn out in photo. This is one of mercury emission lines.

Many thanks for the explanation and the very informative and clever photos - especially the CD.

I'm going to have to try the compact disc photo :thumbsup:.....

Thanks!

EDIT to ADD -
Wikipedia entry on CRI -

" New test color samples
As discussed in (Schanda & Sándor 2005), (CIE 1999) recommends the use of a Macbeth (now X-Rite) color chart owing to the obsolescence of the original samples, of which only metameric matches remain.[13] In addition to the eight ColorChart samples, two skin tone samples are defined (TCS09* and TCS10*). Accordingly, the updated general CRI is averaged over ten samples, not eight as before. Nevertheless, (Hung 2002) has determined that the patches in (CIE 1995) give better correlations for any color difference than the Macbeth chart, whose samples are not equally distributed in a uniform color space."

 

[Bright+]

Many thanks for the explanation and the very informative and clever photos - especially the CD.

It's actually a DVD. The pitch is narrower, which in theory gives a better resolution as a spectroscope. 625 lines/mm for CD vs 1400 lines/mm for DVD

Blue-Ray is 3100 lines/mm. I got to give it a try.

 

[UnknownVT]

It's actually a DVD. The pitch is narrower, which in theory gives a better resolution as a spectroscope. 625 lines/mm for CD vs 1400 lines/mm for DVD

Blue-Ray is 3100 lines/mm. I got to give it a try.

Ah! Have to try again with a DVD - these are CD shots.....

Didn't seem to pick up the missing parts of the spectrum in the CFL.....

Gonna try the DVD.....

 

[UnknownVT]

Ah! Have to try again with a DVD - these are CD shots.....
Didn't seem to pick up the missing parts of the spectrum in the CFL.....
Gonna try the DVD.....

DVD shots (Used DL DVD)

Seemed a quite a bit more difficult to position the DVD to get a nice wide spectrum - almost impossible with the real sun, not so great with the CFL - but the linear tube was pretty easy.

Still don't seem to be able to see or capture the gaps/discontinuous spectrum on the CFL......

 

[Bright+]

I see it. You see multiple distinct blobs on the CFL pics. It's not quite as pronounced with sun or wide spectrum.

The pictures are way over exposed. I think you're way too close to light source.

 

[UnknownVT]

I see it. You see multiple distinct blobs on the CFL pics. It's not quite as pronounced with sun or wide spectrum.

The pictures are way over exposed. I think you're way too close to light source.

Since I basically am not sure what I am doing - I accept your comments.

However for the shots being way over-exposed - they look much less exposed than your examples - the colors are more saturated and looking at the DVD itself mine is much darker - so under-exposed?

Anyway I took your advice and tried again with the CFL

However try as I may I just could not get a bigger spectrum the further away I moved the DVD -
in fact the further away I moved the narrower the spectrum.

These are my most recent attempts with the CFL-

These shots in fact are with the DVD within inches of the CFL - ie: much closer than before.

There is a kind of blobbishness with the second shot - but clearly it is not anywhere as discontinuous or separated as your inset photo.

However I was focusing on the DVD hub area -
but I noticed if I refocus the CFL spiral image got clearer -
so these are re-focused shots - where the CFL image seems a bit clearer -

even though the CFL spiral image is a bit clearer -
I still could not see, or capture the separate images that your inset shot shows.
and these clearly show plenty of yellow and cyan.....

I am willing to try again -
but you may have to please give me "idiot's instructions" on how to set it up so I can also see and capture the separate images of your very telling inset photo.

Just a comment:
If the spectrum were that discontinuous/separated as shown in your inset photo - wouldn't the CRI be pretty low?

The GE 5000K Sunshine CFL is CRI=82, although not great, it is actually pretty respectable?

 

[blasterman]

http://www.cs.cmu.edu/~zhuxj/astro/html/spectrometer.html

 

[Bright+]

Well, it really wasn't about how to take pics, but I took pics so I can show what I meant. To get a visual confirmation, I use the disc 6-7 ft away from the light source, then play with the disc as well as viewing angle.

I can get a separation good enough to tell if the source is triphosphor or continuous.

You'll see multiple clear lines while wide spectrum source looks smooth with no apparent lines (except for the green line, which comes from mercury emission). To get it on photo, just hold the disc the same angle,then look at it from where your eyes were looking from.

Just a comment:
If the spectrum were that discontinuous/separated as shown in your inset photo - wouldn't the CRI be pretty low?

This, I'm not sure. CRI only looks at how standard eight colors shift compared to reference light source at same CCT. So, for a 2700K, the reference would be a regular light bulb adjusted to 2700K with a variable voltage source. It's an old system and its not with a flaw, but its so widely accepted that I think its grandfathered in just like inches and pounds in the US.

The GE 5000K Sunshine CFL is CRI=82, although not great, it is actually pretty respectable?

If the object being viewed responds does not exhibit sharp difference based on light source, then yes. For example, an object that looks purple and responds to reflects red & blue will look purple, but if it's only reflective to violet light, then, it would not look the same in a source that does not contain a violet component.

You saw a significant difference in how neodymium glass looks between triphosphor and wideband, right?

Ultraviolet will also affect appearance in objects that exhibit fluorescence. Fabric brightener is activated by blacklight, as well as natural light, but not by incandescent lamp with minimal UV content.