Here's a simple technique for adding the effect of fake rain to a photo using the free pixel-based image editor Paint.NET. I recently wrote a tutorial for producing this rain effect in GIMP, but know that there are many Paint.NET users and so thought some of you might be interested in this tutorial.
This fake rain effect is quite straightforward and even new users to Paint.NET should have little difficulty following the steps to produce a striking final image.
1. Open a Suitable Image
You can add this stylized effect of fake rain to any image and, if you like, you can produce some quite surreal results, however this technique does work best with images that have the appearance that it could have been raining. I've selected a shot from a dry day, but when the sky was full with dark clouds.
When you've selected your photo, go to File > Open and navigate to your chosen image and click the Open button.
2. Add a Solid Black Layer
This step will add a new layer filled with solid black. If the Layers palette and/or Colors palette are not visible, go to the Window menu and activate them.
Go to Layers > Add New Layer. This layer needs to be filled with black, so firstly check in the Colors palette that the Primary color is set to black. In the Colors palette, there are two overlapping squares and the front one should be black and the drop down menu above it should be set to Primary. If not, set the drop down to Primary and click on the small black square in the color swatches to the bottom of the palette. Now select the Paint Bucket tool from the Tools palette (press the F key) and click on the image. This fills the new layer with black.
3. Apply Noise Effect
The basis of the fake rain is a speckled black and white layer that is produced by applying a Noise Effect.
The new black layer should still be selected, but check the Layers palette and ensure that Layer 2 is highlighted blue. Go to Noise > Add Noise to open the Add Noise dialog. The Color Saturation slider should be dragged fully to the left, but you can experiment with different settings to the Intensity and Coverage sliders to produce different effects. I set the Intensity slider to sixty-five and dragged the Coverage slider fully to the right. Click the OK button to apply the effect.
4. Change the Layer Blending Mode
We can use Blending Modes to change the way that the layer displays and effectively hide the black pixels.
With the new layer still selected, go to Layers > Layer Properties and change the Mode drop down menu to Screen. You'll see that the background layer is now visible, but covered with randomly spaced white dots – these will become our fake rain. Click the OK button to apply the effect.
5. Blur the Dots
Currently the speckled layer might pass for snow, but that isn't the effect that we're after, so we need to blur the dots to make them look more like falling rain drops.
This is a simple step, so go to Effects > Blurs > Motion Blur. In the Motion Blur dialog, there is a circular control with a straight line from the center to the circumference and if you click on that line, you can drag it around to change the direction of the blur effect.
I set the Angle to ninety-seven and the Distance slider to twenty, but you can experiment with these settings to produce different fake rain effects. At this stage, the effect may be exactly what you were hoping for, but there are some more steps that you can take.
6. Use Levels Adjustments
This step strengthens the appearance on the rain drops and makes them a little more random in their spacing.
Go to Adjustments > Levels to open the Levels Adjustment dialog and check that all the R, G and B check boxes are ticked. Now look at the Input Histogram and you'll see a peak in the histogram. You need to drag the arrow handles at the top of the Input slider down to the level of the top edge of the peak and then drag the arrow handles at the bottom upwards until they almost touch the other arrows.
You can then use the top and middle arrow handles on the Output slider to soften the fake rain effect and then click the OK button. If you click on the thumbnail, you can see the settings that I chose.
7. Apply Gaussian Blur
We can use Gaussian Blur to make the fake rain look more natural.
Go to Effects > Blurs > Gaussian Blur and then adjust the Radius slider to one or two.
8. Reduce Layer Opacity
Reducing the opacity of the fake rain layer is another way to make the final effect appear more natural.
Go to Layers > Layer Properties and drag the Opacity slider a little way to the left until you're happy with the effect.
9. Erase Some Rain
This last step will make the fake rain layer less uniform in its density.
In the Colors palette, if the More button is visible, click it to expand the palette. Now drag the the Transparency – Alpha layer to the left to about sixty. Also double check that the drop down menu is set to Primary and the primary color is black. Next select the Paintbrush tool from the Tools palette and in the options bar that appears above the document window, change the Brush Width to give you quite a large brush. You can now paint randomly onto the fake rain layer and you will see that this has the effect of fading the painted areas. Be careful not to overdo this step and go to Edit > Undo if you need to take a step back.