[argyllcms] Re: Targen options

  • From: Ben Goren <ben@xxxxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 3 Sep 2007 10:04:20 -0700

On 2007 Sep 2, at 4:56 PM, Graeme Gill wrote:

> Ben Goren wrote:
>> I added patches at 1-step increments along the L axis, with -1,
>> 0,  and +1  values  for  a and  b. After  removing all  patches
>> clipped at R = G = B  = 0, I had about 900 near-neutral patches
>> that I added to a 1400-patch .ti1 file, for 2310 patches total.
> Sounds like overkill - I doubt  a wider spacing would hurt much.
> Aiming for 100-200 patches might be a more reasonable target.

This has all  been with cheap lightweight  coated stock. I'm going
to  create  a profile  for  some  double-sided coated  card  stock
today. I'll try it with fewer neutral patches and let you know how
that works.

> Very interesting that it made a visible difference.

Previously, there had  been very slight shifts in  a neutral ramp,
barely  noticeable  in  black  and  white  prints. With  this  new
profile, those are entirely gone.

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.

In other words, I think I'm actually bumping up against the limits
of  my printer  /  ink  / paper  combination,  which  is a  rather
impressive place to be. And it's so far from where I started....



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