On Sat, 4 Apr 2015 13:42:55 +0200 Hans Hagen wrote:

On 4/4/2015 1:31 PM, Pavneet Arora wrote:

...

Of and on, I have struggled to find a colour space that is expressive enough for printing, but convenient to access through ConTeXt for day-to-day usage. I find with X11 that the emphasis on screen skews the colours to be brighter than what is desired, especially if one is dealing with coloured stock---say beige kraft---as I am doing with my current bit of typesetting.

In this process I have come across the RAL colour space:

http://www.ral-farben.de/content/application-help/all-ral-colours-names/over...

whose values can be conveniently (sort of) accessed at:

http://rgb.to/ral/page/1

For my immediate needs, I have simply created a set of:

\definecolor[<colourName>][h=HHHHHH]

However, I am wondering if it might make sense to have a colo-imp-ral.mkiv? So my questions would be:

1. Is the RAL colour space a decent one for printing purposes? What would be disadvantages, if not?

2. Does colo-imp-ral.mkiv exist already?

it's not in the distribution so it doesn't exist

...

3. If not, would others find it useful to have a colo-imp-ral.mkiv? If it doesn't then I would be happy to prepare one and submit it.

just go ahead

I have produced both Pantone as well as Roscolux color palates from published web resources for my own use as they are of course copyrighted. One could do the same with a RAL color palatte that is widely used in the paint industry. Of course, none of these really make any sense in printing as one needs appropriate tools to produce the desired result - they will remain an approximation. Alan Roscolux: standard color set used in theater and cinema lighting. (created from www.rosco.com) © Rosco Laboratories 1998-2009

Many thanks Hraban! 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. 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? Warm regards. On 04Apr15, Henning Hraban Ramm wrote:

Am 2015-04-04 um 17:31 schrieb Pavneet Arora :

...

1. Is the RAL colour space a decent one for printing purposes? What would be disadvantages, if not?

No, it’s not. RAL colors are defined only for surface colors, like lacquer (varnish? paint).

Printing colors work differently, they’re mostly transparent. A parallel to RAL in printing colors would be Pantone (or HKS in Germany, Toyo in Japan). But these are copyrighted, so we would be most probably not allowed to ship a library of these. (If I need some spot color, I look up the CMYK/RGB mix in Photoshop or InDesign.)

...

2. Does colo-imp-ral.mkiv exist already?

That would make no sense IMO.

-- ---- Pavneet Arora m: 647.406.6843 Waroc Informatik t: 416.937.9276

On Mon, Apr 6, 2015 at 6:11 AM, Henning Hraban Ramm wrote:

Am 2015-04-04 um 22:00 schrieb Pavneet Arora :

...

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.

Interesting topic. I just add for the record http://wiki.scribus.net/canvas/How_to_legally_obtain_spot_colour_palettes_fo... http://www.selapa.net/swatchbooker/

-- luigi

I just realized that I didn't include the link to the Unix video. Here it is: www.youtube.com/watch?v=tc4ROCJYbm0 -- ---- Pavneet Arora m: 647.406.6843 Waroc Informatik t: 416.937.9276