Am 2015-04-04 um 22:00 schrieb Pavneet Arora <pavneet_arora@waroc.com>:
> This is great insight into the printing world. Of course, Pantone has a
> dominant position on this continent at least, but as you stated, its
> proprietary nature keeps the palette from being distributed easily.
The same is probably true for RAL.
Be aware that RAL is no color system, but just an arbitrary and historically grown collection. In this regard it’s even worse than X11 colors.
There’s also RAL design system, that would be better, but it’s still copyrighted and not suitable for CMYK or RGB devices.
See e.g.
http://en.wikipedia.org/wiki/RAL_colour_standard
http://de.wikipedia.org/wiki/RAL-Farbe
Conversions of RAL colors (that are defined in CIE L*a*b) are just approximations for one special RGB color space, most probably sRGB, and can’t cover everything, since every color space is rather limited.
Conversions of L*a*b or any RGB colors into CMYK depend on several parameters (rendering intent, GCR/UCR), because CMYK color spaces are generally quite small, and you can hit the same color spot with different mixtures of CMYK inks.
> So the question remains: if the X11 colourspace is found inadequate, is
> there another one that we might look for inspiration to create decent
> spot colours for document processing? Even if RAL colours are used for
> varnish, does that mitigate the use of their RGB values for other
> paints? Note, that I am not seeking exact calibration of colours, say
> for branding across different media; just a more expressive palette for
> print applications.
>
> Unfortunately, I don't have access to the Adobe products that you
> mention, and in any case would just want a convenient set of colours
> inside ConTeXt to create documents on the fly.
>
> For this type of work, are there any other "open source" palettes that
> we might look towards?
Spot colors for printing rely on manufacturers that produce those inks/paints.
The existing palettes are defined by (or in cooperation with) manufacturers.
There exists nothing like open source paint recipes, AFAIK, so it would make no sense to define an open source (i.e. freely licensed) palette/system of spot colors.
Of course it’s possible to define a system of (anyhow) matching colors. But that’s so much a matter of taste and application that I wouldn’t start with such an enterprise.
There are some good online tools that help you finding matching design colors, at least for (s)RGB, e.g. Adobe Kuler or paletton.com.
If you need spot colors for printing, you need a (digital or physical) palette from the manufacturers.