Photoshop Blur Gallery and Selections

While recently writing an upcoming post for Fotolia about the Photoshop Blur Gallery and Iris Blur I made a selection and found the difference between selection, non selection and Smart Objects is quite significant, so here’s my take at an explanation;

In this post I’ve exaggerated all the effects to make them clearer. The image used here is ‘Coffee’ File: #61579135 | Author: magdal3na at Fotolia

Selected Blur

If you’re familiar with Photoshop it will be of no surprise that if you have a selection active on a layer, and you run a Blur Gallery filter, the blur will only effect the area selected, but what if the pin is outside the selection?

As you can see here, the blur works as it would if the selection wasn’t present, but only effects the area selected. No real surprise.

Selection Bleed

The blur here only takes the area in the selection into account, meaning that the area outside the selection has no effect on the blur. There may be times when this is not desirable and for this there’s Selection Bleed, found at the top left corner.

By default this is set to 0%, increasing this draws more of the tones from outside the selection into the selected area and thus the blur;

Here’s the same effect, but simplified;

The Blur Gallery and Smart Objects

When it comes to the Blur Gallery and selections, Smart Objects work a little differently.

This time it looks like the selection is having no effect;

However, when you click ‘OK’ you’ll see that a mask has been added to the Smart Filters;

This mask will mask out all Smart Filters, even if you deselect and run some other filter.

Because the blur takes the surrounding pixels into account and then adds the blur there’s no need for the Bleeding Amount, as this is governed by the blur itself. You can manipulate the mask of course, maybe a little Gaussian Blur to help it transition a little better.