[Jeff East]

Hey gang, I have begun taking jobs, and one of the first is a series of slides from a local furniture maker. His existing images are of contemporary woodcrafted furniture shot on an all white background. The only way to see the "floor" is by way of the cast shadow made by the studio lights. He wants to change the background to a blend from light to dark and still retain the shadows. Yikes. how can I cast a realistic shadow made in the 3-d world with photoshop? If necessary, I can post one of the slides tomorrow.
Thanks for the help.

[Jakaleena]

Making real world shadows is actually on my list of tutorials to write. I have just been waiting for a good image to use. When you post your sample, I'll see what I can come up with for you...

[jeaniesa]

Jeff,
I learned this technique in a class taught by Ben Willmore:

1. Let’s say you’ve got a picture with a natural shadow in it (the example in class was a crab against a white background). Select the main subject (Should be fairly easy with the magic wand tool if the subject is shot against a white background - you do NOT want to include the shadow in this selection) and Ctl-J to copy to a new layer. Turn off the layer (eyeball).
2. On the background layer, lighten the background to blend the white of the picture into the pure white canvas. (You want to make sure the white background is pure white, but you still want to be able to see the shadow.)
3. Link the two layers together and drag to a new background image.
4. Change the blending mode of the lower layer (the one with the shadow) to Multiply. This allows the shadows to blend in with new image, but selected item (in this case, the crab) is in normal mode, so it doesn’t blend - it just sits on top.

Let me know if this doesn't make sense and I'll attempt to attach an example of what I've tried to explain with words.

Jeanie

[Jakaleena]

Is this similar to what you're trying to do? I made it from scratch using a red-filled circle selection...

[winwintoo]

How did you do that Jak??

Margaret

[Jakaleena]

It's actually pretty easy to do (you'll have to pretend that the red circle is your product image since I didn't have a real one to work with).

1. Made a circle with the elliptical marquee and filled it with red (for the product image, you would select and copy it to a new file)

2. Duplicated the layer and desaturated it

3. Added omni lighting effect to the red circle to define the light direction and make it a 3D ball

4. Distorted the desaturated layer (Edit > Transform > Distort) until it was placed where I wanted the shadow to be

5. Selected the distorted grayscale circle with the magic wand and filled it with a black to white gradient

6. Used gaussian blur on the distorted shadow until it looked like a shadow

7. Added a layer underneath and filled with black to white gradient

8. Added a drop shadow to the red circle and moved it to its own layer. Blurred, distorted and moved it until it was behind and to the left of the red circle

9. Added texture to the red ball and blurred slightly

10. Burned in the bottom of the red ball until it blended in with its shadow

That's about it...

[docilebob]

jeaniesa , Jak : both good ones. Flexible. Great to add to the tool kit.

Here`s another one. Simple, but effective in may cases ( especially if there is no shadow) :

Separate subject from it`s background, copy/paste to a new layer.

Select object, create new layer below object, fill with appropriate dark color . ( shadows are rarely black)

CTRL+T ( or edit>>transform) select Prespective, Skew, or CTRL+click and drag one control point at a time to stretch the shadow out and away from the light source.

Set to multiply, Blur, adjust opacity to match lighting conditions

If you need to fade it, select the shadow layer, add a layer mask with a white to black radial gradient.

If you need to bend the shadow over another oject, or wall, select that section and transform it by itself.

Does that make sense ?

[Stephen M]

I was recently watching an 'old' video from Bert Monroy on Illustrating with Photoshop (using Illustrator + Photoshop for photorealistic effects)...very timely to this thread as one part was with a tree casting a shadow with fall off onto a wall (I think the same image is in one of his books too).

Study the similar shots if you can find them, or setup real life models and lights using rough shapes and a desk lamp etc...or whip out your trusty 3D app for the same quick primitive/lighting test.

As Jak has demonstrated, you need to consider fall off...as the shadow draws away from the object it becomes lighter and more diffuse. The closer a shadow is to the background, the more focused and dark it will be (depending on lighting), the more fall off the lighter and more blurred it will be...try gradated layer masks for your fall off and or perhaps some gauss. blur and motion blurs etc.

I like to sample the background colour then use the colour palette with HSB sliders to alter the B value to make a darker shadow, then as mentioned multiply blend is used to overprint and mix the shadow (since a true neutral drop/cast shadow is only found on a white background, not to be confused with a shadow endpoint in colour correction though which is usually neutral as it affects the whole image).

For more complex work, distortion may be required to warp the shadow onto existing surfaces...using liquify or distort/displace techniques:

http://members.ozemail.com.au/~binar...V_links.html#D

Hope this helps,

Stephen Marsh.