Blur spilling out of bounds

[iliyak63491322]

Hello.

This is a bit of a longish question.

When I use Gaussian blur or many other blurs (but not all) it tends to either "spill out" or pick up neighboring pixels and average/blur that in and that ends up contaminating the area I am trying to blur.

For exams, if I have a red and white squares next to each other, I want to blur the white, but when I do a little bit of red seeps in and now the white square has a pink tinge. My selections are hard with 0 pixel tolerance/border.

Here are things I have tried and NOTHING works, it always picks up the "wrong" pixels and averages them in.

1. Select, then blur inside the selection.

2. Select, move to the new layer, hit "lock transparent pixels", blur. Still contaminated.

3. Select, move to new layer, re-select (with previously save identical selection, NO new pixels incorporated), hit "lock transparent pixels, blur. Still.

I've turned off the visibility of the underlying layers, kept on, doesn't matter.

Most other filters do the same. I would strongly prefer to use the Gaussian, it is the easiest to utilized, the others are more cumbersome and harder to achieve effects and take much longer to compute. The only one that reliably does not "bleed" is average, but that filter is just crazy difficult to work with.

And here is the FINAL most disturbing thing which happens.

I have even selected, saved the selection, moved it to the new document, closed the original document, (either locked the transparent pixels or left them unlocked, doesn't matter) and then blurred, either selected or not. Same result. The disturbing thing is? There is still contamination from the original subject that has been cut off. It's like photoshop secretly transferred the information about what was inside the empty pixels, kept it in the background and then used it in the calculation.

Here is the actual use.

I have an image of a model and a messy background. I have selected the model and I am trying to blur the background, which is mostly a messy wall that I am trying to "simplify" and make into a solid color. But every time I blur the color of the model and the clothes bleeds outside and contaminates the wall.

I have even done the last thing I described, which is cut out the wall, move the wall into a new document, now with the model area being completely transparent, closed the original image and blurred. PARTS OF THE MODEL AND THE CLOTHES AGAIN BLEED THROUGH AND BECOME VISIBLE AS A FAINT GHOST ALONG THE PERIPHERY OF THE IMAGE.     OMG, I simply had to type this in capitals. Think about it. PS secretly kept the information about what is in the transparent pixels and moved it over to the new document? I mean does that even make any sense? You think the pixels are transparent but PS is using the the remembered pixels in calculation. I saved the document, closed it, opened again, it still "remembers" what was inside the cut out transparent area.

I have posted on other forums asking for help. About half the replies said they cannot reproduce the problem and when they blur nothing bleeds outside the selected area. I don't understand. PS is latest version, no bugs that I can detect, fully updated. But this has always happened with every version I used.

Help.

Thank you

[Chuck Uebele]

Lens blur doesn't do this. Unfortunately, you can't set it as strongly as gaussian blur. You can apply it several times thought.

[Semaphoric]

What I do is to select the subject, and duplicate the layer, and hide the duplicate. Then in the original (a copy of the original, of course), I use the Smudge tool to smudge the background into the subject. Smudge mostly in perpendicularly  from the subject's edges, except when there's a strong linear area nearby; there, stroke in the direction of that area. Tedious as Hell, but it will remove the edges of the subject.Then Gaussian Blur this layer.

Now, make the duplicate layer visible, and add a Reveal Selection Layer Mask.

I will admit that this method is a royal pain, so I only use it when the results of a straightforward blur are unsatisfactory.

[Chuck Uebele]

Yes, that's another way to do it, Semaphoric , cloning into the area also works, and sometimes using content aware fill will work, to get rid of the bleeding area.