How to Add Rainbow in a photo

Now lets learn how to add realistic Rainbow to a photo

Open an Image in Photoshop

 

Add a new Layer
Go to Layer - New - Layer or simply click Shift+Ctrl+N
Name new Layer Rainbow

Select  Gradient Tool , make sure Rainbow layer is selected

Click on the Gradient Picker in the Options Bar, a list of additional Gradient will appear then choose special effect

A window will pop up asking if you want to apply special effects then click Append









Now Go back to Gradient Editor and select Russell's Rainbow

Make sure Radial Gradient is selected

As per below image, now Drag out a rainbow gradient from right to left in the image then release your mouse

Now press Ctrl+T to be able to reposition the rainbow as you desire

Change blend mode Of The Rainbow Layer To Screen

Go to Filter > Blur > Gaussian Blur, to apply Gaussian Blur into the rainbow

Add blur into the rainbow until it looks soft and natural

With Rainbow Layer selected ,add a Layer mask 














You will see a white box appearing beside Rainbow layer

With Gradient tool selected, Go to gradient options and select Black,white

Choose "Linear Gradient" From The Options Bar

Drag A Black,white Gradient On The Layer Mask so that we can make rainbow appear brighter as it reaches into the sky

well, below is final result