On this video Colin Smith from PhotoshopCAFE takes a look at how you can add highly realistic shadows to composite images in Photoshop.
The first step is going to be removing your subject from the background. Now that we have the subject on a white background. From here on Smith explains each step (and there are a few methods – the drop shadow method seems to us a little bit more simple). Our aim will be to transform the basic drop shadow and turn it into a cast shadow which looks much more realistic in a real image.
Using the free-transform and the warp-tool to turn the drop shadow and make it look more like a cast shadow. However just transforming the shadow is not enough – you need to change the opacity but also change the way it looks by adding another layer and blending both of them with a gradient (there are quite a few steps here).
There are quite a few steps on this video and we didn’t go over all of them. If you do want to go over all of them and try it yourself, you can check out the written guide for this video which you can find here.