Path: utzoo!attcan!uunet!ogicse!uwm.edu!zaphod.mps.ohio-state.edu!mips!apple!sun-barr!newstop!sun!concertina!fiddler
From: fiddler@concertina.Sun.COM (Steve Hix)
Newsgroups: comp.sys.mac
Subject: Re: mac screens (9")
Message-ID: <132060@sun.Eng.Sun.COM>
Date: 20 Feb 90 18:45:51 GMT
References: <9312@portia.Stanford.EDU>
Sender: news@sun.Eng.Sun.COM
Lines: 33

In article <9312@portia.Stanford.EDU>, thewho@portia.Stanford.EDU (Derek Fong) writes:
> One weird thing I've noticed is that all the Apple ads show the Mac with
> a "blue tinted" screen.  Does anyone know why this is done?  Does apple use
> a special filter in their promotion ads to avoid glare from the camera's
> flash, or am I missing something?

No special filter.  Absolutely no flash. (!)  (Using a flash would
almost certainly overpower the screen's light output so that you'd see
what looked like a Mac that wasn't turned on.  The camera's shutter has
to remain open at least long enough to cover a full screen paint,
typically using 1/30th of a second to make sure the whole paint is
completed, even a flash that didn't wash out the screen would not last
nearly long enough.)

Color films have different spectral sensitivities than your eye.  Films in general
tend to be much more sensitive to the blue end of the spectrum than
your eye.  (There are some exceptions...but in general this is true.)
In this case, the blue component of the screen's phosphor output shows
up quite strongly on film.

We'll ignore the brain's ability to ignore rather strong color shifts
to make things seem to be whatever color we think it "ought" to be: A
picture taken under fluorescent light with daylight film, for example,
often has a strong green cast, while if you were in the same room,
you'd see the light as pretty neutral.

The film most likely used for those product shot, btw, would be Kodachrome 64.
I'm not that fond of it, but most advertisers go for it.

------------
"...Then anyone who leaves behind him a written manual, and likewise
anyone who receives it, in the belief that such writing will be clear
and certain, must be exceedingly simple-minded..."   Plato, _Phaedrus_