Re: minutes, SVG WG Seattle F2F 2011 day 3 - SVG Color

Hi Nick,

I think this is a case where you want to ignore the profile that is attached
to the image and swap it out with the destination profile instead.

There was a discussion at the f2f why we would need to swap out the attached
profile. This seems to be a valid use-case for such a feature.

Rik Cabanier

On Mon, Aug 1, 2011 at 12:07 AM, Nick Hofstede <
Nick.Hofstede@inventivegroup.com> wrote:

> Quick note on the black preservation:
>
>    ChrisL: last issue is preserving black.
>    ... For example, in ICC if you specify cmyk(0,0,0,1),
>    color-management systems tend to have a switch that specially treats
>    that value.
>    ... So even if the system does color-manipulation normally, that one
>    color will instead stay solid, total black.
>    ... This is so black text stays pure black and doesn't mix in other
>    colors.
>    ... So, similarly, we need to see if we need it, and see if it's an
>    input or output feature.
>
>    cabanier: We have it in InDesign, and it's an output feature there.
>    ... So we have some special cases there again; you don't want to
>    preserve black on an image.
>
>    ChrisL: So that's basically actually being an input feature.
>
>    heycam: Does it make sense to have this controllable on images, or
>    if we can magically just apply it to solid-color fills and strokes?
>    ... Also, if you have some colored shapes which are composited
>    together, and you happen to get black out of that, should that be
>    preservable?
>
>    TabAtkins_: So it sounds like we can just specify that solid-color
>    strokes and fills automatically preserve black, and nothing else
>    does. It can be applied on output, and doesn't need to be specified
>    on input.
>
>    cabanier: So we look at the operator on printing - if a shape is
>    filled with an image or gradient, we don't preserve black. If it's
>    filled with a color, we preserve.
>
>    TabAtkins_: So if you composite a partially-transparent gradient
>    over a black rectangle, you wouldn't preserve the black in it.
>
>    heycam: So basically, for any image, track if the result color comes
>    partially from a gradient or image. If so, don't preserve black;
>    otherwise, preserve it.
>
>    TabAtkins_: So it sounds like we can do this automatically at the
>    end, and thus don't need a property for it.
>
>    heycam: And in PDF, it's not controllable; it just happens
>    automatically.
>
> I'm not sure automatically deciding when to use black preservation is a
> good idea. I don't think you can always deduce it automatically and I think
> you should therefore be able to specify it.
> Consider the use case talked about here for example:
>
> http://www.blog.spoongraphics.co.uk/articles/the-ultimate-guide-to-designing-with-black
> If you would create this in SVG your underlying rectangle would become
> black-preserved black, and the black from the image would be rich black.
> You're going to want to be able to trigger rich black on the solid-color
> fill.
>
> With kind regards,
>
> Nick Hofstede
>
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