Is there a best practice for suggesting/campaigning for new CSS features?

[chrishanel]

I'm a designer who uses HTML/CSS to produce broadcast graphics. Because this use case isn't exactly what the creators of the spec had in mind, I understand I'm sometimes going to run into limitations or conflicts with my own desires.

However, there is one omission that has always bothered me: Blend modes were added to CSS without an additive (linear dodge) option, which would cover 90% of the situations where I would want to use a blend mode for a graphic. Considering how much influence it seems that Adobe's list of blend modes had on what was added to the spec, I'm confused why one of the most useful on the list didn't make the cut.

This is one of the rare times where I feel I can make a thought-out and well-reasoned argument for why something should be added to the CSS spec. However, looking at the W3C website, I have very little clue where discussions like this happen, or how one would join them. Do you have any pointers or advice?