Gaussian Blur Filter in Photoshop Tutorial

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By Andrew Buckle, Updated : 2021

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How to use the Gaussian blur filter in Photoshop, how to use this as a smart filter, with channels, with selections, how to combine effects and more



1. Where is the Gaussian blur filter

You can find the filter in Photoshop via the filter menu and blur and Gaussian blur. It can be used on smart objects, type, layers, images and more


2. Basic use of the Gaussian blur

It blurs, it is a powerful blur and pretty quick. You can apply very subtle blurs by setting the radius value to a low setting or you can totally blur an image by pushing it to the limits though the higher the setting, the slower the response.


Or go for an extreme with a high radius setting


3. Apply the Gaussian as a smart object

Unless you are going to use brushes or manipulate the pixels of an image, you can always convert the current layer before any Gaussian blur filter and turn it into a smart object via the layer menu and smart objects and convert to smart object. You can then attach any effects applied to the current layer or image and the blur is then easy to remove as well as easy to edit and you can double click the blur and the panel will re-appear and you can edit it.


You can also add multiple smart filter Gaussian blurs and then move them around and they can all have different settings or strength of blurs and can be blended with the lower filters. You can also add an image menu and adjustment into the mix.


4. Gaussian blur filter and selections

You can apply your Gaussian blur to the entire image which is fine but if you want to apply the effect to only a small part off the image then you can use selections to limit it. You can use a variety of selection tools but at the most basic of levels go to the rectangular marquee tool and then add over a part of the image and then apply the effect. There is a limit to this approach is that the selection is created before you apply the blur and them can't be changed later. That is the case if you use it as a normal layer.


If you convert the layer to a smart object then you can add your selection as normal and then add the Gaussian blur but now you will see the selection as a mask and you can add to the mask as well as change the mask as well as clear it etc.


Select the mask thumbnail for the smart filters for that layer and then go to the shape tool and set the color to white and add that as a pixel design to the thumbnail, that area will now be blurred in the same way as the earlier selection


5. Gaussian Blur and clipping masks

You can also use clipping masks made out of vector shapes to control the range of the blur via the Gaussian blur. You can select a layer and if you want convert it into a smart object and then add some vector shapes, any shape design as long as it is a shape layer and then drag that shape layer to below the image layer and with the image layer selected go to the layer menu and select create clipping mask.


You can also select the current layer and apply the Gaussian blur and the blurring effect will only appear based on the generated shapes and the rest of the layer will be transparent. If you wish to see the rest of the image, just duplicate the original image and have that below the clipping mask.


6. Gaussian Blur with channels

You can use the blur in RGB but if you display the channels panel found via the window menu, you can select the red channel and then apply the Gaussian blur to that with one setting and then select the green channel and apply a different setting for that and so on with the blur channel.


7. Gaussian Blur and New channel

You can also create a new channel via the channels panel. You can select the current image and paste this into the alpha channel and you can then apply effects such as the Gaussian blur filter as well as the neural filters or displace filter etc and that effect will modify the alpha channel. You can then go back to the standard RGB and then go to the select menu and use the load selection command and load that alpha channel with the blur. You can then use that with gradients etc or [perhaps copy and paste that layer using the selection and then add a layer style such as bevel to the new channel and the bevels can be nearly unlimited with different contours and embossing etc.