H. Lehnerer Photography

How To Simulate Fog

This tutorial will show you how to simulate fog. I will use GIMP http://www.gimp.org to show you the different steps, but you can probably transfer these steps to many other photo edit programs.

1. Load photo

Load you original image. This for example may look good with some extra fog.

2. Create two new layers with black background

Create two new layers with a black background.
Go to //Layer//New Layer…//
Name the first layer “Solid Noise” and the second “Plasma”

3. Create fog with Solid Noise filter

Turn the “Plasma” layer off and select the “Solid Noise” layer. Now we are ready to create the first type of fog. Go to //Filters//Render//Clouds//Solid Noise…//

I used the settings: Randomize, Turbulent, Detail=3, X=4, Y=4
Play a little with the setting. Uncheck Turbulent to have a less chunky fog. Smaller numbers will give you bigger chunks. Now give this layer a Gaussian Blur

Go to //Filters//Blur//Gaussian Blur…// and you are done with this layer. I can used a Radius of 60.

4. Create fog with Plasma filter

Turn off the “Solid Noise” layer and turn on the “Plasma” layer and select it

To create the second type of fog go to //Filters//Render//Clouds//Plasma…//

I used the settings: Randomize, Turbulence=3
Play a little with the Turbulence setting to see the difference.

Now we have a colored fog, so we need to desaturate this layer. Go to //Layer//Colors//Desaturate//.
Again a Gaussian Blur with the a radios of 60 and we are done with this layer

5. Transform black background to transparent

Well, not completely done. We have fog but we cannot see the background photo. We have to transform in both layers the black to transparent. Turn both layers on and select the “Plasma” layer. Go to //Filters//Colors//Color to Alpha…// and change the color button from with to black.

Now do this also with the “Solid Noise” layer. And you should see something like this:

6. Add Layer Mask to blend some fog out and adjust the Opacity

Sometimes it is better if the fog does not go all the way very strong to the top. To change this, we can add to the layer a Layer Mask. Select first the Plasma layer and go to //Layer//Mask//Add Layer Mask…//

Now do this also with the “Solid Nose” layer

Select the Gradient Tool with a linear shape.

Select the Layer Mask of the “Plasma” layer and create a Gradient over the 1/5 part from the top. Select the Layer Mask of the “Solid Nose” layer and create a Gradient over the 1/3 part form the top.

If the for is to strong you can also adjust the Opacity of the “Plasma” and “Solid Noise” Layer

7. The Result

That was it! Play a little around with the setting. Maybe turn a layer off and on, or adjust the levels and curves, saturation and briteness.