Here is a really handy visual guide to lighting. We’re always banging on about the importance of getting light direction and shadows right in your Photoshop work, so here’s your chance to really study how it works. With this knowledge on board, your Photoshop images will look even more realistic.
Just light
The light is positioned at approximately 45º behind the objects. Notice how the sphere receives light on the side in shadow from the cube and cone.

Long shadows
As the light is angled further up, the top of the sphere becomes lighter and the shadows still remain long.

Light becoming evident
The sphere and the cone are growing much lighter now because the light source is becoming more overhead.

Different shades
Even though the light is moving above the objects, the cube still remains much darker, because of its straight sides.

Cone almost light
Shadows are much shorter now. Notice the lack of shadow on the cone. This is due to the cone’s sloping sides.

Barely any shadow
Almost directly overhead, the light slices the sphere with the bottom half in shade but only the bottom 5 per cent in complete shadow.

Light directly overhead
The light is at 90º overhead now; the shadows are limited to the base of the objects, and the cube still appears darker.

Shadows change direction
As the light moves in front, the shadows start to move away from the camera. The sphere still has shadow because of the overhanging shape.

Almost no shade
The light is much further forward
and the cone almost has no shade, while the sphere shadow is subsiding.

Cube becoming lighter
As the light is now much lower in front of the objects, the cube is beginning to look like the other objects.

Shadows cast by cube and cone
At this stage the sphere looks like an inversion of the starting position, with shadow being cast from the cube and cone.

Evenly lit
Now the light is at 45º in front of the objects and they are evenly lit, with slight shadows on the edges away from the camera.












[...] Light study: Understand shadows in Photoshop. http://www.photoshopdaily.co.uk/news/light-study-understand-shadows/ [...]
nice tips … very handy and helpful !
Goo breef introduction to how the basic light effects different objects!
Here’s a link to a Photoshop tutorial with an example of how light and shadow can be retouched on a picture. Light and Shadows in Photoshop
great link thanks : )
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