Re: Do I need to upgrade to i1Profiler? With respect to UV
Re: Do I need to upgrade to i1Profiler? With respect to UV
- Subject: Re: Do I need to upgrade to i1Profiler? With respect to UV
- From: Ernst Dinkla <email@hidden>
- Date: Mon, 11 Apr 2011 12:11:00 +0200
On 04/11/2011 11:01 AM, Graeme Gill wrote:
Ernst Dinkla wrote:
So M0 ISO category and corresponding to the color temperature little UV.
Relative to it's main power, yes, but what's import with paper that
contains
FWA (OBE's), is the relative power at the wavelengths that are absorbed
and re-emitted, and they are not so different for A. So this illuminant
does trigger noticeable FWA activity in reflectance measurements.
(ie. 300-400nm power is roughly 30% that of 400 to 450).
Graeme Gill.
I see that 1:3 power represented in the spectral plot for an illuminant
A lamp and I have the FBA effects measured in my paper white spectral
plots made with the UV enabled Eye-One.
While making the plots I wondered about the limitations on UV
illumination in this spectrometer. I was more interested in the relative
FBA effect of all the papers than absolute numbers but nevertheless even
then it could misrepresent the actual FBA effect in viewing conditions
and possibly create odd effects in profile creation.
My concern is that UV illumination going deeper into short wave
territory could reveal more/different FBA effects and also another TiO2
white absorption/reflection. FBAs can vary on their short wave stimuli.
The SpectroCam lamp plot shows maybe 10x the power of an illuminant A at
350 Nm and it is unlikely to drop straight after that. In the software
it will all be normalised but starting from different stimuli it will be
impossible to normalise all papers equally. I think that FBA content in
papers differs much more than most assume
With D50 still considered a nice average for viewing conditions I could
see good reasons to use Illumination A based Spectrometers without an
UV-cut filter and D50 based Spectrometers with a (mild) UV-cut filter.
The last theoretically a better solution with a smaller extrapolation
step to D50. Less UV though related to Tom Lianza's remark about the UV
content in viewing lights which I interpret as being too low for D50
norm. There is/was a SpectroCam version with UV filter BTW.
--
Met vriendelijke groeten, Ernst
| Dinkla Grafische Techniek |
| www.pigment-print.com |
| ( unvollendet ) |
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