How to Add Rainbows in Photos ~ LA PENSINE MUTINE (EN)

Since colour is the theme of the week, I will provide a technique to add a realistic rainbow within an existing picture. I'm using Paint Shop Pro X but you may get the same type of effects with any other equivalent image editing software such as Photoshop or GIMP. Don't forget to download the rainbow gradient and put the format your software requires in its gradient folder.

Materials

a landcape photo
Rainbow gradient (PSP/PS/GIMP formats)

Instructions

1. Open a copy of the image you wish to manipulate.

2. Add a new layer and draw a 50px high horizontal plain raster line width-wise (if you draw your line in vector mode, you'll have to convert it to a raster layer) using the provided gradient in linear mode (no repeat, no angle) as filling colour. Your gradient must be set in inverted mode or else you can still flip your line vertically afterwards. Make sure your line is in the middle of the layer.

NOTE: Since to the top pixels of my line weren't smooth, I drew a rectangle selection above it overlapping the “hard” pixels using a 4px feathering then I clicked on the Suppress key. Thus I got blurred edges (do not forget to unselect once you've erased the top part).

3. Apply the Warp effect (to give the line an arc shape ):

Horizontal = 0
Vertical = 40
Size = 100
Strength = 60

4. Apply Motion Blur effect (angle 0°, intensité 20%).

5. Add Noise (4% - uniform - monochrome).

6. Position the rainbow where you want and set blend mode to Overlay en and opacity to 80% for a natural look.

For the above variation, I used a different rainbow gradient, drew a thicker line keeping the same ratio and erased the parts overlapping the skyscrapers save for the white one in the background.

Feel free to experiment with blend modes and if your picture contains reflective surfaces (such as water), remember to reflect your rainbow by duplicating its layer and changing its opacity, blend mode, size and orientation according to the kind of effect you wish to create. But why should you stick to landscapes? This technique may also apply to portraits or other types of pictures to create surrealistic effects. When it comes to creativity, there are no limits, no censorship, so let's be wild and burst the colours!