How to Add Fake Snow to a Photo With GIMP

Create a wintry scene

This tutorial shows how easy it is to add the effect of fake snow to a photo using the free pixel-based image editor GIMP. You can also learn how to add fake rain to a photo using GIMP, but you can use this technique to give a wintry feel to all sorts of images and this could be ideal for many of your festive projects. Ideally, you'll have a photo of a scene with snow on the ground, but it isn't essential to successfully complete this project.

Open a Photo

If you have an image with snow on the ground, that might be a good choice, but you can produce fun and surreal effects adding fake snow to all sorts of photos.
Go to File > Open and navigate to your selected image and click on it to select it before clicking the Open button.

Screenshot of Open Image dialog box in GIMP

Add a New Layer

The first step is to add a new layer that will become the first part of our fake snow effect.
If the foreground color in the Toolbox isn't set to black, press the 'D' key on your keyboard. This sets the foreground color to black and the background to white.

Now go to Layer > New Layer and in the dialog click on the Foreground color radio button, followed by OK.

A screenshot of GIMP with the New Layer command highlighted

Add Noise

The basis of the fake snow effect is the RGB Noise filter and this is applied to the new layer.

  1. Go to Filters > Noise > RGB Noise and ensure the Independent RGB checkbox isn't ticked.

    A screenshot of the RGB Noise window in GIMP with the "Independent RGB" option highlighted
  2. Now drag the Value slider until it's set to about 0.70.

    A screenshot of GIMP's RGB Noise window with the Value slider highlighted
  3. Drag the Alpha slider all the way to the left.

    A screenshot of GIMP's RGB Noise window with the Alpha slider highlighted
  4. Click OK. The new layer will now be covered with specks of white.

    A screenshot of GIMP's RGB Noise window with the OK button highlighted

Change Layer Mode

Changing the layer mode is as simple as you could hope for but the results are quite dramatic.

In the top of the Layers palette, select the drop-down arrow to the right of the Mode setting and select the Screen setting. The result is quite effective as it is for the fake snow effect, but we can tweak it further.

A screenshot of GIMP with the Screen blending mode highlighted

Blur the Snow

Applying a little Gaussian Blur can make the effect slightly more naturalistic.
Go to Filters > Blur > Gaussian Blur and in the dialog set the Horizontal and Vertical inputs to two. You can use a different setting if you prefer the appearance and you may indeed have to if you're using an image of a significantly different resolution.

A screenshot of GIMP's Gaussian Blur window with the Size X and Size Y sliders highlighted

Randomize the Effect

The fake snow layer is quite uniform in its density across the whole image, so the Eraser Tool can be used to fade out parts of the snow to make it appear more irregular.

Select the Eraser Tool and in the Tool Options that appear below the Toolbox, choose a reasonably large soft brush. You can now paint randomly over the layer with the Eraser Tool to make some areas more transparent than other areas.

A screenshot of GIMP with the Eraser tool highlighted

Duplicate the Layer

The effect currently suggests quite light snow, but it can be made to look heavier by duplicating the layer.

Go to Layer > Duplicate Layer and a copy of the fake snow layer will be placed above the original and you'll see that the snow seems heavier now.
You can play with the effect further by erasing parts of this new layer or adjusting the Opacity slider in the layers palette. If you want a fake blizzard, simply duplicate the layer again.