Gaussian Blur

 

Do you want to separate your subject from the background? In this tutorial on Gaussian Blur I will show you exactly how it’s done!
So let’s get started.

1. Bring up your image and choose the Polygonal Lasso from the Toolbox.

 

Before you proceed:

 

Go up to the Options Bar. Make sure New Selection and Anti-alias are ticked and Feathering is set to 0 pixels.

 

2. Zoom in and ‘Make A Selection’ around the outline of the subject by clicking from one point to the next.

Hold down the space bar to drag your image around. Clicking to fast will result in the selection completing itself and moving too far between clicks could result in the selection looking a little bit jagged. So take your time with this process.

When you have come back to the start of your selection marching ants should appear around the outline of the selected subject.

 

3. Refining the Selection. If there are areas you want to remove from your selection, do the following:

• Click the Subtract from Selection icon in the Options Bar.

• A minus will appear next to the Polygonal Lasso.
• Now click around the parts you want to Subtract from the Selection.
• In the Options Bar click Refine Edge and use a feather amount of 0.5 pixels and the smoothness to 0.
• Click ok.

 

4. Start Blurring. We are now going to copy the subject onto a separate layer. With the ‘marching ants’ still active open the Layers Panel.

 

5. To copy the subject go to Layer in the Menu Bar > Click on New in the drop-down > and pick Layer via copy.

 

You should have “Layer 1″ on top off your background Layer.

 

6. Now click on the Background Layer. Click on Filter in the Menu bar > Click on Blur in the drop-down > and chose Gaussian blur > Choose a radius of around about 20 -30 pixels and click ok.

(For this example I used 10).

The background should now have an out-off-focus appearance.

 

7. Remove Fringing. If you get fringing around your subject follow these steps:

Click on the Clone Stamp Tool from the toolbox > In the options bar set the size to 150 pixels, set Mode to Normal & Opacity 100%, make sure Aligned is ticked and All Layers is unticked.

 

8. Clone out the Fringe. Hold down the Alt Key on the keyboard. Click once to sample an area outside of your selection that hasn’t been fringed. Release the Alt Key and start painting up and around the subjects edge, removing the Fringing or Halo effect. Don’t worry if you paint over your subject.

By clicking on Control and Z you can see that the fringing has been removed. Click on Control and Y to redo it.
If its not looking right sample the different areas of the background and just keep experimenting until your happy with the results.
If you get any choppy looking areas go to the Healing Brush Tool and use it in the same way as the Clone Stamp Tool.

Last but not least we are going to add a sprinkling of Digital Noise.

 

9. To add Digital Noise click on the “Layer icon” in the Layers Panel.

 

Before you click on New Layer, make sure “Layer 1″ is highlighted.

Your new Layer should be completely blank or transparent.

 

10. Click on Edit in the Menu bar > Click on Fill Layer in the drop-down > Choose 50% Grey > Click ok to exit the panel.

“Layer 2″ should now be filled with grey.

 

11. Click on Filter in the Menu bar > Click on Noise > Choose Add Noise.

 

12. In the Add Noise Panel set the Amount to 10% > Set the Distribution to Gaussian > tick Monochromatic at the foot of the panel and click ok.

 

13. At the top of the Layers Panel Where it says Normal, click on that and go down to the blending mode that says Linear Light.

 

The background Layer will now be showing through. The effect at this stage is a little over the top but thats easily fixed.

 

14. Click on the Opacity Slider in the Layers Panel and drag that down to 20 -30%. What this does is blend in the smooth areas and the sharp areas of the portrait giving it a more natural appearance.

(I used 5% in this example).

So there you have it. Using the Gaussian Blur effect your subject is portrayed against a background that is slightly out-of-focus putting the viewers attention where you want it to be – on the subject!
Of course there are refining methods that you can follow on from this, for example, if your working with hair and it has that unnatural sharpness to it and you want it to blend in naturally with your background this can be achieved easily by using the Eraser Tool. You can also create a Shallow depth-of-field effect which basically means putting the parts of the subject that are closer to the lens slightly out-of-focus.
Adding these subtle touches produces a natural and awesome looking image which is really noticeable when you go to print it out.

 

Before:

 

After: