[argyllcms] Re: Targen options

  • From: Ben Goren <ben@xxxxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 3 Sep 2007 20:12:31 -0700

On 2007 Sep 3, at 4:52 PM, Graeme Gill wrote:

> Ben Goren wrote:
>> The  print  has some  ever-so-slight  metamerism;  it's a  hint
>> greenish in  sunlight (similar to  my Kodak grey card,  but not
>> as  bad), and  almost magentaish  under some  daylight-balanced
>> fluorescent tubes  I've got  in the kitchen. I've  never really
>> noticed the metamerism before; I think the (very subtle) shifts
>> in hue with previous profiles swamped it.
> [ Nomenclature police: Metamerism is  when colors with different
> spectral responses match. Metamerism failure is when colors that
> should match, fail to match. ]

If you taught  classes / seminars / etc. on  color management, and
if you  were on the  same side  of the planet,  I'd sign up  in an

Anyway, I  made a  3696-patch target this  afternoon, with  220 of
those  patches  being  near-neutral  colors; I  did  the  same  to
generate them  as last time,  except incremented the L  counter by
four instead of one.

The test print I made I did  using a device link profile as in the
other thread. I  used gamut  mapping from  the file...but  my test
print file includes  a Grainger rainbow, so that  bit was probably

Nevertheless, the print is simply amazing.

The  most  previous  test  print  I did  I  had  used  Photoshop's
color  engine.  Tonight's  test  print is  fractionally even  more

But  there's  so  much  more  detail  --  and  yet  it's  so  much
smoother...and skin tones just look ``right''....

It's actually  almost as  if the Photoshop  version were  behind a
piece of plastic  wrap. At first glance the  Argyll version almost
looks brighter -- but, at the  same time, the deepest shadows look
darker...all sorts of fine detail is  right there, plain as day in
the Argyll print that's little  more than smudges in the Photoshop
one...the brightness is really pretty close; the Photoshop version
just looks muddy in comparison.

Is Photoshop's  color engine  really that bad,  or is  Argyll that

> To have  any significant impact on  this you need to  be able to
> play  with  the  black  in the  print. Generally  raising  black
> levels  improves  neutral  robustness under  different  lighting
> conditions. Often  this  is  at  the  cost  of  a  more  visible
> screening  and banding  artefacts. light  black and  light light
> black  inks help  make this  more palatable. You  need a  direct
> driver (RIP) and other tools to play this game though.

I've wished  for such on  a couple occasions. I don't  suppose you
have any suggestions for one that works with a Canon i9900 on OS X
(or a  free Unix (preferably  OpenBSD))? I sure haven't  found any
that cost less than four times  as much as the printer that looked
like they were any good....

Anyway...again, thank you!



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