Re: [Gimp-developer] Layer modes: Add vivid light blend mode?

[Øyvind Kolås <pippin gimp org>]

On Mon, Jan 23, 2017 at 12:58 PM, Laxminarayan Kamath
<kamathln gmail com> wrote:
> Hi all!
>
> While you guys are at it, I encourage you to try out this formula:
>
> E = (2 * I ) - M
>
> I call it the "Opposite" mode. I derived it from how the unsharp mask
> does the sharpening - first run a grain extract and then do a grain
> merge.
>
> It is not useful in an awful lot of places. But when you want to
> de-convolute in a strange way, and you have the procedure or a plugin
> which does only the convolution, "Opposite" layer mode can help you
> get there quickly!

This is similar to something else I have experimented with, permitting
opacity values below 0% and above 100% for normal mode, this permits
implementing unsharp mask with a blur layer - as well as increasing
saturation by blending a color image with it's desaturated variant.

/pippin