Re: [Openexr-devel] 3dsMax OpenEXR support

[Richard Annema]

Hi Darrin,

In an ideal world, they probably should be. But in a world where printers,
scanners, film recorders and related software often operate in DPI (dots per
inch) this (pixels per inch) is probably the wiser real-world option.

In the end, the number is relatively arbitrary though; whether you consider
it to be pixels per inch, or pixels per 25.4 millimeters, there's no factual
difference. It just doesn't make for a very nice-looking number.  The same
'problem' is present in the printed circuitboard industry. Many of the units
are based on 10ths of inches, but most design software readily shows these
as 2.54mm units. Cheaper than moving base units to an exact 2.5mm and
redesigning every hardware manufacturing plant.

The same way of thinking holds true for north american non-metricity. Even
though various plans were accepted and launched to convert over, it's
generally thought that converting at this point would present an
unacceptable situation in terms of cost of conversion, education of the
population, etc.
As a fine example : a friend from Texas says she would hate it if things
moved to metric because the travel distance from Houston to Dallas would
'seem' to be higher when it's listed on the roadsigns as as 402km, rather
than 250miles.

But that's gone far enough off-topic, and I'm merely speculating. But legacy
units would seem to me the reason behind the "pixels per inch" for xDensity.

Best regards,
Richard Annema



----- Original Message -----
From: "Darrin Cardani" <address@hidden>
To: "Drew Hess" <address@hidden>; "Steve Blackmon" <address@hidden>
Cc: <address@hidden>
Sent: Tuesday, April 15, 2003 21:16
Subject: Re: [Openexr-devel] 3dsMax OpenEXR support


> Just curious - why are sampToNits and focus in meters and xDensity in
> inches? Shouldn't they all be either metric or English?
>
> Darrin
> --
> Darrin Cardani - address@hidden
> President, Buena Software, Inc.
> <http://www.buena.com/>
> Video, Image and Audio Processing Development
>
>
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