Re: Question about tone remapping with Relative Colorimetric Rendering
Re: Question about tone remapping with Relative Colorimetric Rendering
- Subject: Re: Question about tone remapping with Relative Colorimetric Rendering
- From: Louis Dina <email@hidden>
- Date: Sat, 01 Jun 2013 19:36:39 -0500
Scott/Terry:
Thanks for the answers. I figured converting to Relative Colorimetric with
BPC turned OFF for a given paper would give me the numbers of what I'd get
on paper, but it doesn't. I suspect the Info Palette shows the converted
numbers that are being passed along to the printer driver. Then the driver
does its thing. Absolute Colorimetric does the job and gives me the numbers
I was looking for. It does keep all the in-gamut tones the same and forces
the OOG tones to the border...thanks.
Just to help me understand better, I printed the 0-255 RGB 11-step wedge to
a matte fine art paper using first Perceptual, then Relative Colorimetric
with BPC. This paper has a Dmax of about 15L* and a paper white of 97L*.
The RC print keeps the midtone at the original file value, but scales
everything else toward the middle from both ends. I had always read that RC
intent kept all the in-gamut colors and tones unchanged, but apparently
not, unless I am missing something. Abs Colorimetric keeps in-gamut tones
where they are.
The Perceptual print scales everything and lightens the print overall. That
makes sense, since we lose a lot more values at the dark end than we do at
the light end, so dark values move more.
Appreciate the help.
Lou
> ------------------------------
>
> Message: 8
> Date: Sat, 01 Jun 2013 18:07:56 -0400
> From: Terence Wyse <email@hidden>
> To: Louis Dina <email@hidden>
> Cc: Colorsync Users List <email@hidden>
> Subject: Re: Question about tone remapping with Relative Colorimetric
> Rendering
> Message-ID: <email@hidden>
> Content-Type: text/plain; charset=us-ascii
>
>
> On Jun 1, 2013, at 10:35 AM, Louis Dina <email@hidden> wrote:
>
> > RC Intent has always
> > been described as accurately reproducing in-gamut colors, then clipping
> all
> > out-of-gamut colors and tones, bringing them back to the edge of the
> > destination gamut.
>
> All bets are off when you turn on black point compensation....BPC scales
> the black point of the source to the black point of the destination instead
> of clipping.....it also has a subtle effect on colors as well.
>
> If you want *accuracy*, use absolute colorimetric.....and as Scott eluded,
> have your color settings prefs set to absolute as well if you want a
> accurate readout in the info palette.
>
> Terry
>
>
>
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