Re: UV Filter - DTP70
Re: UV Filter - DTP70
- Subject: Re: UV Filter - DTP70
- From: Jan-Peter Homann <email@hidden>
- Date: Tue, 31 Jul 2007 19:38:25 +0200
Hello Ray,
Just to clear one think:
It makes a big difference, if the UV Filter is applied between
lightsource and measurement sample or between measurement sample an
measurement device.
In the first case, all UV light is blocked and optical brighteners in
the measurement sample are not activated.
In the second case, the optical brighteners in the measurement sample
shift some UV light to the visible spectrum. The shifted UV-light will
not be cut by the UV-Filter.
Most of the UV Filters I know, are in the path between lightsource and
measurement sample.
With i1 Isis, we have the change from tungsten light to LED light.
One interesting question will be, if the i1 Isis LED including UV have
more UV in the lightsource as tungsten lights.
In this case, the measurement of samples with a lot of optical
brighteners could lead to different results between Tungsten and LED
based instruments.
****
Questions:
Is there any information from X-Rite / GretagMacbeth available about the
spectrum of the lightsource in different instruments ?
Is there any information from X-Rite / GretagMacbeth available, if
different lightsources and No UV Filter will lead to different
measurement results for samples with strong optical brighteners ?
*****
Thank you for all your support at the colorsync mailinglist
Jan-Peter
RaymondCheydleur wrote:
IMHO you are both right! It's very tough to satisfy all users when you are
dealing with a technical product. Scientific users demand wording according
to the specifications (UV included/excluded) "Regular" users want a simple
explanation... (UV Filter, no filter).
However when you are in a mixed environment of users the simple explanation
gets complex! A few years ago at an IPA event the form submitted for
measurement had check boxes: ___UV ___No UV Very friendly,
unfortunately also very confusing. Measurements with UV or no UV or is that
with a UV filter, or without a UV filter...
Later versions of the DTP70 manual available on the web specifically include
both the technical terms and parenthetically (UV filter not in use) and
(UV filter in use)
If you don't know what included and excluded mean the web can help there as
well. There has been a help desk article posted on the X-rite web site for 3
years that should help any user (and lets not start a debate on the last
paragraph :-))
http://www.xrite.com/product_overview.aspx?ID=674&Action=Support&SupportID=3
152
-------
UV Included and excluded
The X-Rite DTP70 contains an Ultra Violet (UV) filter that can be moved into
the optical path of the instrument. When this is done the filter blocks
(excludes) UV energy from the measurement.
UV excluded therefore means the filter is being used.
UV included means that the filter is not being used.
It is often desirable to exclude the UV potion of the spectrum when
measuring profiling targets printed on substrates containing optical
brighteners. The DTP70 is shipped from X-Rite with the filter in the
included position. See related support articles on the left to learn how to
move the filter into or out of the optical path.
--------
Thank you,
RayC
Ray Cheydleur
OEM Technical Manager
X-rite Incorporated
<snip>
In a message dated 7/30/07 10:23 PM, Graeme Gill wrote:
Sorry, but I think it's you lot that are being perverse in
wanting to name it after the mechanism used, thereby leaving
yourselves a mental inversion step every time you want to
understand what effect there is on the reading.
Marco Ugolini:
In my own opinion, Graeme, there is a user side and a technology /
manufacturer's side to the tools we use in our work. My natural inclination
is to side with the user, because I'm one too.
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