Photoshopping an object into a picture.

[polarbear_ed]

I'm very much a newbie.

I was experimenting and after looking everywhere for the above question I still couldn't find an answer that suited. I have a photo I've been working on and in it I've attempted to photoshop an iMac on this desk. I've also tried to photoshop a box on the chair.

The photo still doesn't look quite right and I can't get the iMac to look like it's sitting on the desk despite the attempt at shadows and perspective warping etc..

Would I need to deconstruct the stand of the iMac and change it individually? Are the colours wrong?

As for the box I used the pen tool and cut it I've now got a smooth edge but the colours don't match although I think it could has potential if I knew what I was doing.

[Steve]

Think about shadows, you have none.

The back of the chair is dark, the front of the desk is dark, the back of the box is well lit.
The monitor should be casting some kind of shadow on the desk because of the window too.

[ibclare]

I would advise starting over with a good photograph -- if you can. What you have now presents some lighting (and as Steve said, shadowing) challenges. The desk has a glare, though not bad, but the shadows are deep, too deep. At least from what is presented here, there is no detail in the chair nor in the area below the desk. Taking a picture with more diffuse light will give you better, more even results.

Am I seeing a computer shadow thrown onto the window? You have primary and secondary light sources. Look at the notebooks and their shadow direction. An object can have multiple shadows, usually of different density so play with that. The iMac on the box is somewhat faded compared to the monitor. If you want it to be that intensity you'll need to increase saturation. Multiple methods: levels, curves, hue/saturation adjustments for example.

I'd also suggest that you make the stand on the computer more realistic as right now, the picture on the box is more real -- unless you're going for surrealism

Hope our comments help. Show us your results!