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More color spectra

I

Ioannis

Jan 1, 1970
0
I am back in Athens after 2 years in Crete, so I am unpacking all my toys
:)

I have added yet more color spectra of some common light sources on my
website, taken with my hand-held spectroscope.

http://users.forthnet.gr/ath/jgal/spectroscope/amici.html

All spectra are calibrated against each other in terms of nm (with just one
exception where the image was slightly wider) and have been processed with
Photoshop.

Particularly interesting were the results for the 3 CFL triphosphor types, a
regular 2,700K, a cold cathode 4,000K and a Narva 6,000K. Note how the last
one contains excess blue. The shutter, speed and spectrum slit were
identical for these 3.

I will add more spectra as time permits.

Enjoy,
 
I

Ioannis

Jan 1, 1970
0
[snip]
I will add more spectra as time permits.

OK. I have added more available sources to my immediate vicinity, so the
table is now complete in terms of what I can get my hands on. The rest of my
lamp collection is still packed, but most duplicate what's already there.
The Kr and Ar+Ne glow lamps were courtesy of Don Klipstein.

http://users.forthnet.gr/ath/jgal/spectroscope/amici.html

Next in the series are photos with the large spectroscope, but I will limit
those to sections of the solar spectrum to show the Fraunhoffer lines, which
show on this table, but are otherwise a little weak.

Note that the only "true" monochromatic source, is the red diode laser. It
is conceivable that at very high resolutions its red line spreads over more,
but for practical purposes, it's trully monochromatic.

Cheerio,
 
I

Ioannis

Jan 1, 1970
0
Ï said:
Very good work, and interesting to look at. It's nice to see a 3rd
party doing this, instead of relying just on manufacturer's spectral
data (or lack of data).

I have a few suggestions:

I would be interested in comparison spectra of standard incandescent
vs. "full spectrum" incandescent lights.

Well, the only "full spectrum" incadescent I have is a blue glass tinted
Philips incadescent, but unfortunately it is packed along with many of my
lamps in the basement. This is an ongoing project however, so I will add
some more as time goes by. I definitely need to add the LPS spectrum at some
point in time.
Is it fairly easy to either include a wavelength scale, even an
approximate one? Or at least note wavelengths of some of the lines in
some of the specta?

I am working on it as we speak :)

(It is a pain in the butt, because the spectrum comes from a prism, so the
scale is non-linear)
Thank you for doing useful work and sharing it!

You are welcome!
 
V

Victor Roberts

Jan 1, 1970
0
I would be interested in comparison spectra of standard incandescent
vs. "full spectrum" incandescent lights.

This statement indicates the type of confusion that is
created by use of the undefined term "full spectrum."

Considering that standard incandescent lamps are very close
to being blackbody radiators, I can't think of any light
source, except the sun, that has a spectrum that is more
full than incandescent lamps. The "blue"-tinted glass bulb
used on many incandescent lamps to raise their color
temperature actually absorbs energy in a relatively narrow
range of wavelengths. In my opinion, that makes the spectrum
of these incandescent lamps less "full" than a non-filtered
incandescent lamp.

If we are talking about high color temperature filtered
incandescent lamps, perhaps we should call them that instead
of using the term "full spectrum."

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.

This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
 
D

Don Klipstein

Jan 1, 1970
0
This statement indicates the type of confusion that is
created by use of the undefined term "full spectrum."

Considering that standard incandescent lamps are very close
to being blackbody radiators, I can't think of any light
source, except the sun, that has a spectrum that is more
full than incandescent lamps. The "blue"-tinted glass bulb
used on many incandescent lamps to raise their color
temperature actually absorbs energy in a relatively narrow
range of wavelengths. In my opinion, that makes the spectrum
of these incandescent lamps less "full" than a non-filtered
incandescent lamp.

This is true of incandescent lamps whose bulbs are made of "neodymium
glass". "Neodymium glass" has a distinct absorption spectrum, with its
main feature at visible wavelengths being a notable and narrow absorption
band in the yellow, with two points of maximum absorption (one close to
578-80 nm and one close to 589-590 nm).

I have seen the claims of "neodymium lamps" being "full spectrum".

I consider their main benefit being a "color exaggerating effect" - as
in most red objects tend to be rendered more-red and more brightly, and
most green objects tend to be rendered more-green and more brightly, than
under unfiltered incandescent light of the same color temperature.

Neodymium glass, by being bluish, also raises the color temperature.

However, I normally do not consider any of this a reason to use
incandescent lamps that have energy efficiency even lower than usual for
incandescents - the neodymium glass only removes visible light, and does
not make visible light from anything. Energy efficiency of "neodymium
lamps" is less than that of unfiltered incandescents.

Since many "neodymium lamps" with "taller claims" (my words) have
claimed life expectancy of 5,000 hours and vibration-resistant filaments,
I expect their energy efficiency to be significantly less than that of
unfiltered incandescents having 5,000 hour life expectancy and
vibration-resistant filaments. Longer life expectancy and
vibration-resistant filament design both detract from energy efficiency
(which is light output for a given wattage).

The color distortions, despite being at least fairly arguably favorable,
detract from the color rendering index. I don't have an exact figure on
hand but my impression is that neodymium lamps have a CRI around 80, while
unfiltered incandescents have CRI by definition of 100.

There are also incandescent lamps with bluish glass (or bluish coatings)
not involving neodymium. These largely lack any sharp spectral features,
other than often a somewhat to fairly sharp loss of absorption as
wavelength increases from far-red to near-infrared. Sometimes there is
some notable "ripple" in the visible spectrum, but I have never found that
to be truly serious.
My impression is that CRI of those would be in the mid-uper 90's.

My main objection to those is the same as my main objection to
"neodymium lamps" - the filtering removes visible light, reducing the
energy efficiency from that of unfiltered incandescents.
If we are talking about high color temperature filtered
incandescent lamps, perhaps we should call them that instead
of using the term "full spectrum."

Most without neodymium and having color temperature within several
hundred K of 5000 K I would consider candidates for "full spectrum",
except there is no "official definition" of "full spectrum".

I do note that "full spectrum" has no official definition in
"the lighting industry".

I remember a few years ago a thread involving proposal of such a
definition, and I remember proposing such a definition in that thread.
I also remember resistance to any definition of "full spectrum" being
"officially adopted in the industry" (my words) since the biggest winners
of that would be some of the hucksters.
Vic Roberts

- Don Klipstein ([email protected])
 
V

Victor Roberts

Jan 1, 1970
0
[snip]
I do note that "full spectrum" has no official definition in
"the lighting industry".

I remember a few years ago a thread involving proposal of such a
definition, and I remember proposing such a definition in that thread.
I also remember resistance to any definition of "full spectrum" being
"officially adopted in the industry" (my words) since the biggest winners
of that would be some of the hucksters.

It's also possible that an official definition of "full
spectrum" would work against the hucksters, since lamps
claiming to be "full spectrum" would have to finally conform
to some standard.

I think the biggest barrier to standardizing this term is
the many competing definitions - some people think it means
high color temperature, others think it means a continuous
or semi-continuous SPD, yet others may think it means a
reasonable flat SPD from red to blue, while yet others think
it means enhanced near UV and there are probably some that
believe it means a significant amount of near IR (obviously
incandescent lamps already meet this) and/or combinations
of the above. It just makes my head spin :)

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.

This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
 
I

Ioannis

Jan 1, 1970
0
[snip]

I sent you an email, asking you a question. Please reply back.
 
D

Don Klipstein

Jan 1, 1970
0
[snip]

I sent you an email, asking you a question. Please reply back.

Already attempted - return e-mail ran into a problem.

I ask for a valid e-mail address, or else if you know that your e-mail
to me had valid "from" and "reply-to" then we have to speculate as to what
went wrong and how to get around.

- Don Klipstein ([email protected])
 
I

Ioannis

Jan 1, 1970
0
Ï "Don Klipstein said:
[snip]

I sent you an email, asking you a question. Please reply back.

Already attempted - return e-mail ran into a problem.

I ask for a valid e-mail address, or else if you know that your e-mail
to me had valid "from" and "reply-to" then we have to speculate as to what
went wrong and how to get around.

Don,

Use <jgal at ath dot forthnet dot gr> and cc to <jgal at math dot uoc dot
gr>, after the obvious conversions. The address I post with is bogus to
avoid spam. Your reply is needed urgently, as I need the data to construct a
wavelength reference table.

Thanks,
 
I

Ioannis

Jan 1, 1970
0
Ï said:
I am back in Athens after 2 years in Crete, so I am unpacking all my toys
:)

I have added yet more color spectra of some common light sources on my
website, taken with my hand-held spectroscope.

http://users.forthnet.gr/ath/jgal/spectroscope/amici.html

Very good work, and interesting to look at. It's nice to see a 3rd
party doing this, instead of relying just on manufacturer's spectral
data (or lack of data).

I have a few suggestions: [snip]

Is it fairly easy to either include a wavelength scale, even an
approximate one? Or at least note wavelengths of some of the lines in
some of the specta?

I have added an approximate nm wavelength reference table at the end and
corrected the names for 3 spectra which were wrong. I could not establish
all the wavelength references, because my spectroscopes don't have scales,
so this was done by comparison.

Thanks again to Don Klipstein for providing the info about the contents of
the 3 mixed spectra:
Ne+Kr, Ne+Xe 1 and Ne+Xe 2.

http://users.forthnet.gr/ath/jgal/spectroscope/amici.html
Thank you for doing useful work and sharing it!

Next come photos of the Solar spectrum at a resolution of 20,000 :)
 
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