Re: ProfileMaker 5
Re: ProfileMaker 5
- Subject: Re: ProfileMaker 5
- From: Robin Myers <email@hidden>
- Date: Tue, 15 Aug 2006 13:44:18 -0700
Dear Mr. Breton,
On Aug 15, 2006, at 10:37, Roger Breton wrote:
<snip>
My
sources at Gretag have stated that it does not really achieve a full
D65 simulation,
How could it?
but it gets close to a D50 simulated illuminant.
It'd be interesting to obtain from GretagMacbeth (now X-rite) the SPD
of the
unfiltered lamp output vs that of the D65 filtration. Can't this be
measured, indirectly, if I have the T spectroscan and measure in
transmissive mode? Just a thought. I gather that what I'm really after
is
the spectral transmission characteristics of the Lino D65 filter (it
must
the same as in the SpectroEye?)....
I have
not had the time to confirm this with my own measurements but it does
sound plausible.
Yes, it must be attenuating some of the yellow components of the light
source in order to mimic, relatively speaking, the "shape" of the D65
illuminant in the visible region.
I pulled out my measurements of the Spectrolino D65 filter and combined
it with Illuminant A (spectrally shaped close to a tungsten-halogen
bulb) and then compared it to CIE D50. The spectral result does not
match D50. The basic shape of the spectrum from 380 to 600 nm is not
too bad, but the filter produces a large wide peak from 620 to 730 nm
which does not match the D50 illuminant spectrum. However, the CCT of
the Illuminant A/D65 filter is 4624 K, which, assuming the Illuminant A
is about 300 K below a true tungsten-halogen bulb would give a combined
result of about 4924 K, should give a close CCT match to D50.
<snipped>
Regards,
Robin Myers
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