Re: Viewing angle?
Re: Viewing angle?
- Subject: Re: Viewing angle?
- From: <email@hidden>
- Date: Mon, 14 Aug 2006 13:06:11 -0400
Jonathan,
The angle you mention is the "Observer angle", not the
angle used by instrument, which operates in a 45 deg/0 deg
geometry (Illumination angle/measurement angle).
The human sensitivity to color was determined at two
angular inputs into the eye. The 2 degrees Observer,
defined in 1931, corresponds to the central portion of the
eye or, expressed otherwise, to the angle corresponding to
small colored zones, such as the ones in pictures.
From 2 to 10 degrees, the number of color sensors in the
human eye go down rapidly. The 10 degrees Observer,
defined in 1964, corresponds to this extended zone where
color is still perceived, but with a different sensitivity
from the central 2 degrees zone. The 10 degrees Observer
is most often used in paint and textile applications,
where large color patches are usually found.
This said, you can still use a 2 degrees Observer to
measure paint as long as you use a similar reference
thereafter (and that you write it down). However, using a
10 Degrees Observer to make a printer profile is a bad
idea; the color management world of print and displays is
built around the 2 degrees Observer, so I strongly suggest
to do your measurements with this setting.
Danny Pascale
email@hidden
www.BabelColor.com
On Mon, 14 Aug 2006 10:39:44 -0500
Jon Crook <email@hidden> wrote:
What would be the reason for using a 10 viewing angle
instead of a 2
angle? Why doesn¹t my X-Rite 528 have a setting for
viewing color at 10?
--
Jonathan Crook
Prepress Technician
Corporate Image
www.corp-image.com
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