[argyllcms] Re: Difficulty profiling new iMac

On 2007 Sep 14, at 7:54 AM, Graeme Gill wrote:

> Ben Goren wrote:
>
>> Just for  kicks, I just  downloaded the Eye-One  Match software
>> and profiled the display from it. The overall appearance of the
>> gray ramp is,  at first glance, more  neutral. However, what it
>> really  does  is  bounce  back and  forth  between  bluish  and
>> yellowish. It's something like this:
>
> I'd guess that this is the three curves not quite matching. This
> could be due to inaccuracy, or simply quantizing artefacts.

Well, considering  that they're  not sampling  much more  than the
primaries  at about  10  different brightness  levels, I'm  hardly
surprised. Impressed, actually,  that they're  able to do  so well
with so little.

> If the displays and video hardware supported 10 bits or more, it
> might help of course :-(

Someday, probably  only a few  years away by my  guess. Of course,
knowing  my luck,  now  that  I've just  bought  this iMac,  it'll
probably be Monday.

Aren't some of the Eizo displays 10- or 12-bit? But nobody makes a
12-bit video card, if I remember right -- and none of the software
could drive it, anyway....

> I can  certainly see 8  bit (or maybe  that's 6 bit  dithered !)
> banding artefacts if  I look critically at  the MacBook display,
> but then these flaws are  swamped by the terrible vertical angle
> sensitivity the display has. If you angle down low enough to get
> good blacks,  the greys turn  a horrible brown/yellow.   If your
> view  is angled  higher, you  get nice  neutrals, but  the black
> starts to look like there  is something white being reflected in
> the screen  surface. There is no  "good" in between  angle, it's
> one or the other. You'd think a  hot of the presses machine from
> Apple would have something a  bit better than this, wouldn't you
> ? I guess the assumption is  that noone does critical color work
> on a laptop.

Hey, it  could be a *LOT*  worse. My 12" G4's viewing  angle is so
narrow that only about the middle third is ``close.'' Hooked up to
my Mitsubishi Diamond  Pro 2040u, it's been a  great workhorse for
almost four years now,  and I still expect to use it  a lot in the
field -- such  as yesterday when I took it  to the library gallery
to measure the lighting.

The iMac's display is  actually very impressive. The viewing angle
is a  non-issue; you have  to get close  to the critical  angle of
reflection before  it's really noticeable. The glossy  screen is a
bit glossier  than my now-retired  2040u, but it  actually handles
reflections a bit better. (In my living room work environment, the
lights  are such  that  it's  a non-issue.) The  tens-of-thousands
of  patches profile  I  created with  -q  u shows  near-negligible
banding. And, indeed,  now that  I've got  the curtains  wide open
with a  bit of  southeastern sun peeking  through the  window, the
color casts of  the various profiles are barely  noticeable -- but
my  reflection  sure  is! But  for browsing,  email,  etc.,  where
you've  got a  white background,  the reflections  again become  a
non-issue. (Did I mention tha this display is *BRIGHT*?)

Cheers,

b&

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