Creating a Tilt-Shift Effect in GIMP

How to Make a Tilt-Shift Effect in GIMP

Tilt shift effect applied to a photo of a city street

helicopterjeff / Morguefile.com

The tilt-shift effect has become very popular in recent years, perhaps mainly because many photo filter type apps include such an effect. Even if you haven't heard the name tilt-shift, you will almost certainly have seen examples of such photos. Typically they show scenes, often shot a little from above, that has a shallow band in focus, with the rest of the image blurred. Our brains interpret these images as being photos of toy scenes because we have become conditioned that photos with such focused and blurred areas are in fact photos of toys. However, it is a effortless effect to create in image editors, such as GIMP.

The tilt-shift effect is named after specialist tilt-shift lenses designed to allow their users to move the front element of the lens independently of the rest of the lens. Architectural photographers can use these lenses to reduce the visual effect of vertical lines of buildings converging as they get higher. However, because these lenses only focus sharply on a narrow band of the scene, they have also been used to create pictures that look like photos of toy scenes.

  1. Once you've selected a photo, in GIMP go to File > Open and navigate to the file before clicking the Open button.

    Opening an image file in GIMP.
  2. Because we're trying to create an effect that looks like a toy scene, rather than a photo of the real world, we can make the colors brighter and less natural to add to the overall effect.

    The first step is to go to Colors > Brightness-Contrast and tweak both sliders. The amount that you adjust these will be dependent on the photo that you're using, but we increased both the Brightness and Contrast by 30. Select OK when set.

    Adjusting brightness and contrast in GIMP.
  3. Next, go to Colors > Hue-Saturation and move the Saturation slider to the right. We increased this slider by 70 which would normally be excessively high​ but suits our needs in this case. Select OK when set.

    Adjusting the Hue and saturation in GIMP.
  4. Now it's time to duplicate the background layer and then add blur to the background.

    You can either select the Duplicate layer button in the bottom bar of the layers palette or go to Layer > Duplicate Layer.

    Duplicating a layer in GIMP.
  5. Now, in the Layers palette (go to Windows > Dockable Dialogs > Layers if it's not open), select the lower background layer to select it. Next, go to Filters > Blur > Gaussian Blur to open the Gaussian Blur dialog. Check that the chain icon is unbroken so that changes you make affect both input fields – select the chain to close it if necessary. Now increase the Horizontal and Vertical settings to about 20 and select OK.

    You won't be able to see the blur effect unless you click the eye icon beside the Background copy layer in the Layers palette to hide it. You need to click in the blank space where the eye icon was to make the layer visible again.

    Adjusting the Gaussian blur in GIMP.
  6. In this step, we can add a mask to the upper layer that will allow some of the background to show through which will give us the tilt-shift effect.

    Right-click on the Background copy layer in the Layers palette and select Add Layer Mask from the context menu that opens up. In the Add Layer Mask dialog, select White (full opacity) and select Add. You'll now see a plain white mask icon in the Layers palette.

    Adding a layer mask in GIMP.
  7. Select the icon to ensure that it's selected and then go to the Tools palette on the left panel and select the Gradient tool to activate the Blend tool.

    The Blend tool options will now be visible below the Tools palette and in there, ensure that the Opacity slider is set to 100, the Gradient is FG to Transparent and the Shape is Linear. If the foreground color at the bottom of the Tools palette isn't set to black, press d key on the keyboard to set the colors to the default of black and white.

    Blend tool settings in GIMP.
  8. With the Blend tool now set correctly, you need to draw a gradient on the top and bottom of the mask which allows the background to show through while leaving a band of the upper image visible. Holding the Ctrl key on your keyboard to constrain the angle of the Blend tool to 15-degree steps, select the photo about a quarter way down from the top and hold the left Ctrl key down while you drag down the photo to a little above the halfway point and release the left button. You will need to add another similar gradient to the bottom of the image also, this time going upwards.

    You should now have a reasonable tilt-shift effect, however, you may need to clean up the image a little if you have items in the foreground or background that are also in sharp focus. 

    Creating a blend in GIMP.
  9. The last step is to manually blur areas that are still in focus but shouldn't be. In this photo, the wall on the right-hand side of the image is very much in the foreground, so this should really be blurred.

    Select the Paintbrush tool in the Tools palette and in the Tool Options palette, ensure that Mode is set to Normal, select a soft brush (we chose 2. Hardness 050) and set the size as appropriate for the area that you're going to be working on. Also, check that the foreground color is set to black.

    Adjusting the paintbrush tool settings in GIMP.
  10. Now select the Layer Mask icon to ensure that it is still active and just paint over the area that you want to be blurred. As you paint on the mask, the upper layer will be hidden revealing the blurred layer below.

    Manually Blur Areas
    Photo © helicopterjeff from Morguefile.com, Screen Shot © Ian Pullen