Re: What is the best Spectrophotometer for reading canvas
Re: What is the best Spectrophotometer for reading canvas
- Subject: Re: What is the best Spectrophotometer for reading canvas
- From: Roger Breton <email@hidden>
- Date: Fri, 04 Apr 2003 08:51:41 -0500
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I have built profiles using data from integrating sphere spectros. It
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works just fine. I did a comparison beween the X-Rite SP64 and Gretag
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Macbeth Color Eye XTH sphere spectros before purchasing. The X-Rite's
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use a gas filled tungsten bulb for the instruments illumination. The
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Gretag uses a xenon flash bulb. I measured a variety of substrates and a
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variety of different colorants with each of them. They consistently
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measured within 1 Delta E of each other EXCEPT for materials with
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obtical brighteners. The xenon flash bulb in the Gretag excites the UV
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brighteners and causes them to fluoresce significantly more than the gas
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filled tungsten bulb in the X-Rite. Measuring a fabric with optical
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brighteners in it would produce values of about L94 A1 B4 on the X-Rite
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SP64, but would measure L94 A2 B8 on the Gretag Color Eye.
So you ended up buying the SP64? I was told many times and read this in the
litterature that Xenon correlated better with human vision to measure
fluorescence then tungsten. I know I have a Spectrocam and that's the only
instrument of all the affordable and supported color management instrument
I know of that uses a Xenon light source to read charts. To me, a tungsten
light source does not excite enough UV whereas Xenon has plenty of energy in
that region of the spectrum to excite the OB in the paper and will yield
better output profiles. The two types of instruments, as you know, yield
very different type of profiles. Unless one uses a UV filter on its
instrument, but I have had mixed success with my DTP-41uv.
How did the two profiles you did with the ColorEye and SP64 compared?
Roger Breton
Laval, Canada
email@hidden
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