[Openicc] new: Proof colour space

[almccart at lexmark.com]

Hello Jan-Peter and all,

So -- if we were to define a 'proofing colorspace' what would the 
requirements be?
For example:
1. RGB encoding
2. Encompassing and similar in shape to the ISO printing gamut defined in 
ISO 12640-3 Annex B
3. Not significantly larger than the ISO printing gamut defined in ISO 
12640-3 Annex B
4. Unambiguously defined transformations to/from CIE XYZ
5. Primaries placed so that if the file is incorrectly assumed to be sRGB, 
severe hue shifts do not occur.
6. Primaries placed so that HVS response to tone and hue adjustments are 
reasonably homogeneous 
throughout the space [i.e., perceptual isometry].
7. Adapted white point, color space white point and black point 
chromaticity = D50
8. Print-referred image state
9. Adapted white point and color space white point luminance: 160 cd/m^2 
[=ICC PCS]
10. Image surround - 20% of adapted white point
...?

Does this represent a good initial list of attributes? 
Is there an existing public domain RGB that meets these criteria?

Best regards,
Ann McCarthy
Lexmark CPD
Imaging Systems Engineering
ICC Workflow WG Chair 






Jan-Peter Homann <homann at colormanagement.de>
Sent by: openicc-bounces at lists.freedesktop.org
05/02/2006 07:41 AM
Please respond to homann

 
        To:     Kai-Uwe Behrmann <ku.b at gmx.de>
        cc:     OpenICC Liste <openicc at lists.freedesktop.org>
        Subject:        Re: [Openicc] new: Proof colour space


Hello list,
A proofing colorspace would be very helpful.
I know  several photostudios, which are dealing with agencies, prepress 
bureaus and print shops.

They are working in RGB and deliver RGB and CMYK-Files (ISOcoated) to 
their clients.

Before they are converting to CMYK (ISOcoated) with relative 
colorimetric and blackpoint compensation, they do a proof and optimize 
the RGB-file, if colorclipping of saturated colors are occuring.

The goal is to build an archive of RGB-files, where all RGB-files can be 
converted relative colorimetric with blackpoint compensation to the main 
   destination colorspace, without the need to make image by image 
analysis , which rendering intent fits best.

Most uzsers I know prefer to have a special menue for softproofing, 
instead of doing it in the colorsetting file.

Very helpful is also, if the softproof menue is synchronized with the 
menue "convert to profile"

If the softproof is OK, the file can be converted to the destination 
colorspace with one mouseclick.

:-) Jan-Peter


Kai-Uwe Behrmann wrote:
> Hello list,
> 
> what would you think about a dedicated proof colour space?
> 
> The current situation in CinePaint is: we have RGB/Cmyk image data and 
can 
> proof them to whatever colour space on screen. If someone wants to 
> simulate an special output device like a film stock or a print media, it 

> seems there is no sense by sticking to the editing colour spaces 
> (RGB/Cmyk). It is not clear if the user wants a RGB or Cmyk colour space 

> to proof against.
> 
> It could as well mean the proofing options should become a separate 
> advanced configuration group.
> 
> Whats the opinion on the list about this matter?
> 
> regards
> Kai-Uwe Behrmann
>                                 + development for color management 
>                                 + imaging / panoramas
>                                 + email: ku.b at gmx.de
>                                 + http://www.behrmann.name
> 
> _______________________________________________
> openicc mailing list
> openicc at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/openicc
> 


-- 
--

homann colormanagement ------ fon/fax +49 30 611 075 18
Jan-Peter Homann ------------- mobile +49 171 54 70 358
Kastanienallee 71 ------- http://www.colormanagement.de
10435 Berlin --------- mailto:homann at colormanagement.de
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