7 Replies Latest reply: Apr 5, 2014 6:36 AM by Monstrik RSS

    Gausian blur makes pixels transperant near the edge

    Monstrik Community Member

      Can you please tell me how i can make gausian blur treat selection edges as it treats the edges of a photo - it does blur to the very edge...

      but within selection it makes those pixels near the edges of the selection semi-transparent...

       

      blur2.jpg

        • 1. Re: Gausian blur makes pixels transperant near the edge
          c.pfaffenbichler Community Member

          If there is Transparency then that will naturally affect the result of Gaussian Blur.

          What exactly do you wan the result to be?

          • 2. Re: Gausian blur makes pixels transperant near the edge
            Trevor.Dennis Community Member

            Yes, that's the way it works.  Gaussian blur is great for softening transitions as well as content, but to do that, it has to go from fully off to fully on over a distance that depends on strength setting.  That's why it is so go for things like Vignettes, or soft edged layer masks.

             

            If you want a blur that will go all the way to the edge of a selection, but not one pixel more, use either  Filter > Blur > Lens blur, or Filter > Blur > Field blur.

             

            You can also use Iris and Tilt Shift blur with selections.  The effect will still work 100% inside the selection, and 0% outside.  Plus you have the extra control of how the blur operates inside the selection.

             

            OK, this is where you get sorry, because we are setting homework today.  The image below makes a nice test piece for blurring stuff.

             

            Click on it to expand it.

            Right click and chose Copy

            Go to Photoshop Ctrl n (Cmd n)  Ctrl v (Cmd v)

            Add some canvas. Say 100 pixels all round (so 200 pixels for width and same for height)

            Now make a dozen copies of the grid layer.

             

            Alt click the top layer's Eye icon so all the other layers turn off.  Select the top layer and apply a 10 pixel Gaussian blur.

            Alt click the next layer's Eye icon, and select the layer. Now Ctrl click the layers thumbnail to load it as a selection, and Ctrl f to repeat the Gaussian Blur

             

            Both test give exactly the same result.

             

            With the other layers try:

             

            Lens Blur with no selection.

            Lens Blur with the entire grid selected.

            Lens Blur with a selection dragged across just the centre two thirds of the box grid.

             

            Do the same with Field blur, and if you are not bored, have a go with Iris and Tilt shift.

             

            You are now an expert at blurring stuff, and can stay here and be our resident expert after changing your user name to ‘Monstrik the Blur Expert’.

            Box Grid.jpg

            • 3. Re: Gausian blur makes pixels transperant near the edge
              Semaphoric Community Member

              One thing you can do is make a duplicate layer, and use the Smudge or Clone Stamp tools to extend the non-transparent area into the transparency. Content-aware Fill might work, too. Blur the result, Select > Load Selection original layer transparency, and use that for a layer mask on the blurred layer.

              • 4. Re: Gausian blur makes pixels transperant near the edge
                Trevor.Dennis Community Member

                Or just duplicate the layer as many times as you need.  

                • 5. Re: Gausian blur makes pixels transperant near the edge
                  c.pfaffenbichler Community Member

                  Or use Layer > Layer Mask > From Transparency and blur the Layer, but not the Layer Mask (white may bleed on, though).

                  • 6. Re: Gausian blur makes pixels transperant near the edge
                    Trevor.Dennis Community Member

                    or do what I said in post #2, and use Lens or Field blur.  Both give similar results inside the selection, and the effect goes undiminished all the way to the selection, but not one pixel further.  For me, that was by far the best feature about those alternative blur methods, as I no longer have to repair blur bleed around composites.

                    • 7. Re: Gausian blur makes pixels transperant near the edge
                      Monstrik Community Member

                      Guys thank you very much for your answers... I learned from this one