7. Mark out on the options' bar the
Radial Gradient.
Represent after that a gradient's line.
Open the
Gaussian Blur (the menu
Filter > Blur > Gaussian Blur) and insert the
20 value in the
Radius field.
8. Change the layer's
Blending Mode with the rainbow circle on
Screen. Using
Move Tool you can place the rainbow on any part of the image.
9. Use
Gradient Tool again and select the gradient preview on the options' bar and click again on the small black pointer, choosing this time the
Reset Gradients.
Find the
Foreground to Transparent

but on the options' bar we must mark out the
Linear Gradient.
Draw a line with the same tool from the bottom to the top part just to damp down the lowest part of the rainbow.
10. Erase the unnecessary parts of the rainbow, applying the
Eraser Tool.
11. Let's create now the rainbow imitation.
Create New Layer and fill it with white color.
12. Insert now the noises, using the
Add Noise filter. The
Amount parameter must have the value of
100. Mark out the
Uniform mode and tick on the
Monochromatic.
13. Select in the menu
Image > Adjustments > Levels, moving the black slider on a quarter of the axe.
14. Blur out the noises, applying the
Gaussian Blur selection out of the Blur group. The
Radius option
0.8 pixel.
15. Let the picture through the
Motion Blur filter, changing the
Angle parameter on
60 and the
Distance on
60.
16. Apply after that the
Plastic Wrap filter of the
Artistic group. Give it the next parameters:
Highlight Strength — 20,
Detail — 14,
Smoothness — 3.
17. Open up
Filter > Other > High Pass. Select for the
Radius the value of
70.
18. Finally lay over the
Motion Blur filter with the same parameters mentioned above, changing the layer's
Blending Mode on
Hard Light and
Opacity - 20%.
Experiment On!