one form BobH on mired

[T3D john bercovitz <bercov@xxxxxxxxxxx>]

Here's one that Bob sent from his address that got changed slightly.
It got stopped at the border.
John

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RE: In discussing color correcting viewers and lamps etc. John says,
by the way what is the mired that allows adding filter nos. etc.?

Like the diopter is a reciprocal meter..e.g. 2 diopter lens has half
meter focal length, 3 diopter has 1/3 meter focal length etc.
A mired is a reciprocal Kelvin deg number. In this form that can be
added and subtracted like the diopters!
Now having said that I will look it up!
MIRED Acronym for Micro-reciprocal-degree. Reciprocal measure of
color temperature. The mired value of light source is its color
temperature in kelvins divided into one million. Equal mired
differences correspond to equal visible changes in color. Mired
values being reciprocal, are smaller as the kelvin figure increases.
They are convenient units when characterising a source, a filter or
a film because the values are additive, i.e. the mired value of a
source plus the mired value of a filter is the sum of their separate
mired values. The mired values of the photometric filters will affect
whatever the color temperature of the light source.
Focal Dictionary DA Spencer
BobH


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