How to Blur a Background in GIMP

Tuesday, June 28, 2011  at 6:58 AM
Learn to replicate the look of SLR camera by creating an out-of-focus background and focused subject.  Welcome to the eleventh article in my Photography Editing in GIMP series!

Previous articles:

Article 1: Easy Photography Editing in GIMP
Article 2: How to Crop in GIMP
Article 3:  How to Control Saturation in GIMP
Article 4: How to Control Contrast and Lightness
Article 5: How to Change Color Photos into Black and White
Article 6: How to Level a Horizon
Article 7: How to Correct a Skewed Perspective in GIMP
Article 8: How to Square All of Your Corners in GIMP
Article 9: How to Adjust Curves in GIMP
Article 10: How to Adjust Color-Specific Saturation in GIMP


These tutorials use the free photo-editing program GIMP.  I am not being paid to endorse GIMP--I just really like it!
Create a Blurry Background

This post will show you how to take your photos from this (with an apparent wide depth-of field):

Village in Morocco by Danalynn C

to this (with an apparent narrow depth-of-field):

Village in Morocco by Danalynn C

Step 1: Open your photo in GIMP and select the Magic Scissors button (the button in the toolbox that looks like a pair of scissors).

Village in Morocco GIMP tutorial by Danalynn C

Step 2: The Magic Scissors tool works by forming a line at the point of highest color gradient--where the color changes the fastest, which is usually at a border.  Start by clicking a point on the edge of your object.  Now click a point along the edge, but slightly further along.  A line should be between them, following the edge.

Sometimes Magic Scissors gets it wrong.  This is fine!  Just click on the incorrect line between the two points that you have made and drag that line back to the appropriate spot.  This will create an additional point where you have clicked.  Then, continue working your way around the object.  I find that if the object has a sharp outline, such as a silhouette, I will need fewer points than if the object's outline is fuzzy or a similar color as the background.

Village in Morocco GIMP tutorial by Danalynn C

Step 3: Once all of the points have been selected, if you hover your mouse is over this original point then a symbol of two interlocking circles should appear.  Click here.

Village in Morocco GIMP tutorial by Danalynn C

Step 4: Left click inside your outlined shape to cause the edges to become dashed.  You may need to click twice. 

Village in Morocco GIMP tutorial by Danalynn C

Step 5: Right click inside your selected figure and select Edit, then click on Copy Visible.

Village in Morocco GIMP tutorial by Danalynn C

Step 6: From the Layers tab on top, click New Layer.  Nothing will appear to happen, which is fine.

Village in Morocco GIMP tutorial by Danalynn C

Step 7: Click paste (or click Ctrl+V).  Click "Yes" to all of the dialogue boxes.

Village in Morocco GIMP tutorial by Danalynn C

Step 8: To help us see what we are doing, we will open the Layers Dialogue Box.  Click on the Windows Tab, then under Recently Closed Docks select the Layers, Channels, Paths...option.

Village in Morocco GIMP tutorial by Danalynn C

You will get this:

Village in Morocco GIMP tutorial by Danalynn C

Step 9: With just a regular mouse (click on the Toolbox icon with four arrows), click on the part of your new layer that is not inside your selection.

Village in Morocco GIMP tutorial by Danalynn C

Step 10: In your Layers Dialogue Box, click on the layer titled Background.

Village in Morocco GIMP tutorial by Danalynn C

Step 11: Now you are controlling only the background and you can edit it as a normal image.  Whatever you do will not affect the object you outlined, since you have pasted a copy of that object into the foreground (the next layer up).  If you wanted to make the background black and white, but keep the subject in color, you could now do that to this background layer by simply following the steps in my tutorial for turning images into black and white. However, this tutorial will show you how to blur the background.  To do that, select the Filters tab, then under Blur click on the Gaussian Blur button.

Village in Morocco GIMP tutorial by Danalynn C


Step 12: The box that popped up lets you control how much blur you want.  I usually just accept the default blur and then blur it again if it is still too crisp, but if you know that you want a lot of blur then you can control that via the Blur Radius option. Increasing the Blur Radius to 10 instead of the default 5 will give you quite a noticeable blur.

Village in Morocco GIMP tutorial by Danalynn C

Step 13: For most photos, be careful not too blur too much!  If you do, it will look like you just cut and pasted an image onto a fake background.  This is why I tend to do my blurs only a bit at a time.  For this image, I used the default Blur option twice.

Village in Morocco GIMP tutorial by Danalynn C

Step 14: Save your final photo after blurring the background.

Village in Morocco GIMP tutorial by Danalynn C
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