(no subject)
(no subject)
- Subject: (no subject)
- From: Samer Mady <email@hidden>
- Date: Fri, 11 May 2001 10:58:07 +0200
Hi,
>
When measuring density, the usual result is a number (for example 1.4).
>
Does this measurement result have a label? In other words is the result
>
referred to as points, or degrees, something else?
the density hat no unit. the density is computed as the follows: log(1/R)
where R ist the Reflectance. the Reflectance has no unit. the reflectance
describes the procentage of light being reflected by the color patch.
>
How about the scale - is it a linear scale or a log scale?
the scale is a log scale. sometimes people claim that the use of a log scale
hat something to do with the light perception. this is not true. the
brightness perception can be described by a power function. the reason of
the use of a log function is that we get smaller simpler numbers.
>
If I measure with my tools and get a "status T" density is this different
from other types of
>
density values?
the status T relates to the spectral transmitance function. if you have for
an example a green color patch and y want th measure how much cyan the color
patch includes y have to use a red filter. Desitometers use calculted
filters. A status A is a U.S.A standard and a status E is a europien
standard.
samer mady
email@hidden