Re: [csswg-drafts] [filter-effects] color-interpolation-filters initial value

Okay, that text has been there (and thus, the spec has been self-contradictory) for a while. The [25 November 2014 WD](https://www.w3.org/TR/filter-effects/) also says that, while later [contradicting it](https://www.w3.org/TR/filter-effects/#FilterPrimitivesOverviewIntro):

> The color space in which a particular filter primitive performs its operations is determined by the value of the property color-interpolation-filters on the given filter primitive. A different property, color-interpolation determines the color space for other color operations. Because these two properties have different initial values (color-interpolation-filters has an initial value of linearRGB whereas color-interpolation has an initial value of sRGB), in some cases to achieve certain results (e.g., when coordinating gradient interpolation with a filtering operation) it will be necessary to explicitly set color-interpolation to linearRGB or color-interpolation-filters to sRGB on particular elements. Note that the examples below do not explicitly set either color-interpolation or color-interpolation-filters, so the initial values for these properties apply to the examples.

What I suspect happened is that `sRGB colorspace` was used loosely to mean the set of primary chromaticities and whitepoint of sRGB, without considering the transfer function. That makes sort-of sense, as the three values are "use sRGB", "use sRGB but in linear light space" or "pick either of those depending on speed and accuracy". In turn, this clearly distinguishes these filters from, say, the Adobe Photoshop-compatible blend modes (which are in the NTSC colorspace, or at least use the equations for that space to calculate `luma`).

So, what I think we need:
- revert the change that made auto be the initial value. That is not Web compatible.
- clarify the color space description.

I'm happy to propose better text for the clarification.

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Received on Friday, 21 September 2018 19:52:02 UTC