re: Epson 5500 Metamerism (was: Re: Not a Rocket scientist)
re: Epson 5500 Metamerism (was: Re: Not a Rocket scientist)
- Subject: re: Epson 5500 Metamerism (was: Re: Not a Rocket scientist)
- From: Dan Reid <email@hidden>
- Date: Wed, 29 Aug 2001 14:07:37 -0600
On Wed, 29 Aug 2001 09:16:03 +0000, Terry Wyse <email@hidden> wrote:
>
on 8/29/01 8:12 AM, Udo J. Machiels wrote:
>
>
> I am Duo J. Machiels and I am doing some investigation in this problem what
>
> they call metamerism.
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>
>
> My article was: Profiling Epson Pro 5500 with archival inks.
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>
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> Hope the follow-up from Terry Wyse will help you.
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> As far as I did come with my own investigation, his suggestion is to use a
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> measuring device which does have an UV filter installed like the one from
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> him.
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>
>
>
I think one of the things I will try today is going thru all the filters
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that come with the Spectrolino (No filter, UV, D65 and Polarizer) and see
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which comes closest to giving me a decent profile with the 5500 with a
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minimum of editing necessary.
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>
I thought it was very interesting that Andrew Rodney stated that on a 10000
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that he profiled recently that the proof was closest when viewed under
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tungsten light. I've found the EXACT SAME THING with the 5500. When put in
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my 5K viewer they are consistently too green/yellow but when pulled out and
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viewed under household incandescent they look pretty good. Could be that
>
Epson has somehow "tuned" the inks/5500 to work best under typical tungsten
>
lighting?
Tungsten bulbs have a rounded spectral power distribution kind of like a
bell curve. D50 simulator fluorescent simulator bulbs by their very design
have problems getting a close *spectral* match to D50. Typically you see a
large spike in, guess what, yellow/green region and blue/purple. Which is
another reason to create digital camera profiles under daylight or tungsten
lighting even though you shoot under different lighting.
Remember your ICC profiles are built with D50 reference illuminant. Color
matching between devices is happening based on an *assumed* viewing
condition being close to D50. Since fluorescent tubes have spikes while
tungsten is more of a bell curve you see definitely redder/orange prints but
not color distortions because of the light source. Also fluorescent tubes
don't excite the UV portion similar to D50 or daylight. I found engaging a
D50 fluorescent tube AND and UV bulb made the perceived color a lot better
than just D50 fluorescent tubes.
A U/V filter on the spectro definitely helps in minimizing metamerism
issues. The fluorescence in papers and inks can fool the spectrophotometer
as been discussed ad infinite um. Eliminating the flourscent brighteners
from the printer profiling equation has always helped me and never caused
problems.
The only real success I have had of late with the Epson 2000P and scanner
based measurement is with Monaco's v2 of Ez-Color. They have devised a
special table that *definitely* improved the quality of the profile in
comparison to competing products. The profile editing tools are much more
advanced than competitor products and allow separate A2B and B2A editing.
Editing of the preview independent of the output is crucial to get the
previews to sync with the output of 2000P.
Epson 2000P w/ Sem-glossy paper has some UV brighteners in them but not a
heck of a lot like their other papers. You can quickly tell by viewing under
a *black light*.
--
Dan B. Reid
RENAISSANCE PHOTOGRAPHIC IMAGING
Color Imaging Solutions Provider
http://www.rpimaging.com | email@hidden
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