I want to blur the sky so that only pixels in the selection are used in computing the new values. Also, I need to use a large blur radius. I've done this in the past by starting off with a small blur raidus and progressively reducing the selection, increasing the (gaussian) blur radius as I did so. What is the simplest way to do this? If I just apply a gaussin blur with a large radius to my selection is uses values outside the selection in calculationg the new values near the boundary of the selection.

On Sun, 2009-05-31 at 08:39 +0200, Sven Neumann wrote:

Hi,

On Sat, 2009-05-30 at 21:24 -0500, Leonard Evens wrote:

I want to blur the sky so that only pixels in the selection are used in computing the new values. Also, I need to use a large blur radius. I've done this in the past by starting off with a small blur raidus and progressively reducing the selection, increasing the (gaussian) blur radius as I did so. What is the simplest way to do this? If I just apply a gaussin blur with a large radius to my selection is uses values outside the selection in calculationg the new values near the boundary of the selection.

Copy your selection, paste it to a new layer and blur that layer. Does that give the desired result?

I don't believe so. I tried it. It still used pixels outside the selection in computing the new pixel values in the desired region. In this case, those values were zero, so that lightened the region at the edges.

I think there may still be some way to do it using layers, but I haven't figured out how.

Sven

On Mon, 2009-06-01 at 19:25 +0200, Sven Neumann wrote:

Hi,

On Sun, 2009-05-31 at 08:12 -0500, Leonard Evens wrote:

Copy your selection, paste it to a new layer and blur that layer. Does that give the desired result?

I don't believe so. I tried it. It still used pixels outside the selection in computing the new pixel values in the desired region. In this case, those values were zero, so that lightened the region at the edges.

Zeros would not lighten the edges, but darken them. What Blur did you use at all?

Of course you are right. My problem was that I copied the selection into a new layer with transparency as the fill type. I don't really understand what happened, but it appears the transparency was being averaged, so after the gaussian blur, the selection in the new layer appeared to fade out at the edges, thus looking "lighter". I don't use transparency controls much, so I will have to reeducate myself in the subject to understand what happened.

I've tried it again, using white as the fill type. This time the selection got whiter near the edges. That is not what I want.

Maybe there is some way to do this to get it right, but as of yet I don't know what it might be.

Sven