How to separate the shadow from the background?

Question

Adobe Photoshop

Almost everyone knows how to separate an image from the background, but what if we have a soft shadow? You can draw it yourself, but there is not enough skill to make it realistic (I don’t understand how the shadow will form, I don’t have enough imagination), and it takes a ton of time. Many pictures already have shadows, and I'm sure there must be a technique for separating these shadows.
I found a tutorial , but everything is on a white background. I now need to cut out this sofa , it does not have a very complex shadow, but the background is not filled either. Tell me how would you do it? And in general, the question of shadows from objects is very worrying, maybe some really useful manuals, except for how to "draw with a brush and blur". Thanks to all.

Answer 1

I would cut out the couch and cut out the shadow. Combine to taste.

Answer 2

Did you even watch the video to the end? Or just looked at the beginning, saw a white background and immediately got upset? It looks like the second))
There, on several machines with different backgrounds, all operations are performed. From about the fifth minute , different backgrounds are shown, non-uniform and not white like those of the sofa at the link. Just do the same as in the tutorial.
For shadows, read drawing books or google tutorials like " how to draw realistic shadow" . As you understand with simple objects, it will be possible to move on to complex ones. The general principles remain.
Just blurring black shadows is always the worst option, only if you don’t care about the quality of the final image at all or you need a shadow purely for show. More precisely, you can blur, but you need to adjust the degree of blur based on the distance from a specific point of the object to the place where the shadow from this point falls on the surface. And in diffused light it is even more difficult)))