Spectral Data of MacBeth ColorChecker
Corvin Idler
(at best 380 to 780 nm in at least 10nm increments)
Corvin Idler
Fredrik Lönn
colorchecker, but got a call from a sales representative who didn't seem to
know of any such data. From what I've heard, the ColorChecker is a selection
of chips from the Munsell book of colors and as such should have published
spectral data.
Let's hope someone here has theese data!
Best Regards,
--
Fredrik Lönn
Substitute "c" for "x" in e-mail address to reply.
"Corvin Idler" <id...@uni-koblenz.de> wrote in message
news:b7m76l$voc$1...@news.uni-koblenz.de...
Roger Breton
id...@uni-koblenz.de wrote on 4/17/03 8:40 AM:
I have a dataset measured by my X-rite DigitalSwatchBook, for what it's
worth. Just let me know off-list if you're interested.
Roger Breton
Robin Myers
>
> Are there any data concerning the spectral reflectivity of the 24 patches of the GretagMacbeth ColorChecker chart available online?
> (at best 380 to 780 nm in at least 10nm increments)
Which version? The Macbeth ColorChecker (currently named the
GretagMacbeth ColorChecker) has undergone many different formulations
over the years that have changed the spectra, but not the colorimetric
values.
The original aim spectra for the ColorChecker patches were described in
"A Color Rendition Chart" by McCamy, Marcus and Davidson in the Journal
of Applied Photographic Engineering, Summer Issue 1976, Vol. 2, No. 3,
pgs. 95-99.
However, as noted in the article, the aim spectral reflectances were
never completely achieved and so some of the patches never functioned
effectively as intended (e.g. the blue flower patch never turns pink in reproduction).
Over the intervening years the formulations have changed, presumably as
a cost saving measure (Macbeth's cost, not the purchaser's). I have
measured the spectra of at least 5 different vintage ColorCheckers, from
1977 to the present and there are several distinct formulation changes.
So, if you want spectral data, it would be best to measure your specific
chart to not run afoul of a vintage mismatch.
Robin Myers
Corvin Idler
"Robin Myers" <ro...@rmimaging.com> schrieb im Newsbeitrag news:3E9EC528...@rmimaging.com...
> Corvin Idler wrote:
> >
> > Are there any data concerning the spectral reflectivity of the 24 patches of the GretagMacbeth ColorChecker chart available
online?
> > (at best 380 to 780 nm in at least 10nm increments)
>
> Which version?
> The Macbeth ColorChecker (currently named the
> GretagMacbeth ColorChecker) has undergone many different formulations
> over the years that have changed the spectra, but not the colorimetric
> values.
too bad...
> The original aim spectra for the ColorChecker patches were described in
> "A Color Rendition Chart" by McCamy, Marcus and Davidson in the Journal
> of Applied Photographic Engineering, Summer Issue 1976, Vol. 2, No. 3,
> pgs. 95-99.
> However, as noted in the article, the aim spectral reflectances were
> never completely achieved and so some of the patches never functioned
> effectively as intended (e.g. the blue flower patch never turns pink in reproduction).
> Over the intervening years the formulations have changed, presumably as
> a cost saving measure (Macbeth's cost, not the purchaser's). I have
> measured the spectra of at least 5 different vintage ColorCheckers, from
> 1977 to the present and there are several distinct formulation changes.
Do you know when they changed the formula/spectra the last time?
> So, if you want spectral data, it would be best to measure your specific
> chart to not run afoul of a vintage mismatch.
Hm.... seems that I won't get around it...
> Robin Myers
Thanx
Corvin
Earl F. Glynn
of the GretagMacbeth ColorChecker chart available online?
> (at best 380 to 780 nm in at least 10nm increments)
Try this FTP site.
ftp://ftp.eos.ncsu.edu/pub/spectra/
The README there says
munsell.description - The specification of the 64 Munsell chips in Munsell
book
notation. Chip descriptions preceded by "MCC" come from the Macbeth Color
Checker chart.
I don't know if this really answers your question, but it seems like it
might.
--
efg -- Earl F. Glynn, Overland Park, KS USA
efg's Computer Lab: http://www.efg2.com/Lab
Mirror: http://homepages.borland.com/efg2lab/Default.htm
Color Science page
http://www.efg2.com/Lab/Library/Color/Science.htm
Corvin Idler
> ftp://ftp.eos.ncsu.edu/pub/spectra/
>
> The README there says
>
> munsell.description - The specification of the 64 Munsell chips in Munsell
> book
> notation. Chip descriptions preceded by "MCC" come from the Macbeth Color
> Checker chart.
>
> I don't know if this really answers your question, but it seems like it
> might.
> efg -- Earl F. Glynn, Overland Park, KS USA
Thanx a lot.
Jim Worthey
are in the actual Color Checker?
The ftp site given is a wonderful resource. Reflectances are given for
120 Dupont paint chips, 64 Munsell chips (including the Color Checker
chips), and 170 natural and man-made objects.
Earl F. Glynn wrote:
> "Corvin Idler" <id...@uni-koblenz.de> wrote in message
> news:b7m76l$voc$1...@news.uni-koblenz.de...
>
>
> Try this FTP site.
> ftp://ftp.eos.ncsu.edu/pub/spectra/
>
> The README there says
> ... Chip descriptions preceded by "MCC" come from the Macbeth Color
> Checker chart.
Corvin Idler
"Jim Worthey" <jwort...@SPAMstarpower.netTHANKYOU> schrieb im Newsbeitrag news:3EA77A53...@SPAMstarpower.netTHANKYOU...
> Reflectances are given for 9 of the Color Checker chips. How many chips
> are in the actual Color Checker?
But there is another version availible with much more Patches (ColorChecker DC)
Regards
Corvin
Cliff Rames
> (at best 380 to 780 nm in at least 10nm increments)
>
> Corvin Idler
http://www.cis.rit.edu/mcsl/online/
Follow the "CIE data" link for 380 to 780 nm, 5 nm increments, both
Excel and text files. They say "Data are from N. Ohta Colorimetry."
Regards,
Cliff Rames
