Spectrophotometers vs. Densitometers: was Spectrolino as a densit ometer
Spectrophotometers vs. Densitometers: was Spectrolino as a densit ometer
- Subject: Spectrophotometers vs. Densitometers: was Spectrolino as a densit ometer
- From: Ray Maxwell <email@hidden>
- Date: Thu, 29 Aug 2002 11:25:48 -0700
A densitomenter has the following parts that change over time:
1. The lamps spectral characteristics.
2. The filters fade (spectral bandpass changes)
3. The spectral response of the sensor varies from unit to unit and over
time and temperature.
The calibration method used for densitometers does not have any way to
correct for the variation of the changing spectral characteristics.
A densitometer is only good for relative readings. It is fine for getting
the density constant across a press sheet. However, the accuracy of the
numbers that are read out is never as good as a spectrophotometer.
The density reading errors will vary depending on the spectral
characteristics of the media and inks that are being read when you use a
densitometer.
The calibration methods used for a spectrophotometer allow the instrument to
normalize out all of the effects listed above. The density status filters
are just weighting factors stored in the program. These numbers do not
change over time.
If you are trying to print to standard densities or trying to exchange
density data with other people, the spectrophotometer is the only way to go.
Spectrophotometers and Spectrodensitometers are worth the extra money if you
want accuracy.
Ray
P.S. Creo is not an instrument manufacture.
Creo
Ray Maxwell | Senior Color Systems Engineer, Inkjet Printing
4225 Kincaid Street | Phone (604) 451-2700 ext. 2004
Burnaby, B.C.
Canada V5G 4P5
IMAGINE CREATE BELIEVE
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