Chroma key and parabolic umbrella?
problem with white is, when I separate the subjet in photoshop,theres a little white border, sure I can refine edge until it looks right, but then putting a single solid color looks wierd, in needs some gradient/shadows.. again its doable in photoshop but I tought that "gradient" would stay with a green screen color replacement?
First, green is fine for videos where the motion hides the green that can show up on the edges of the subject or through translucent clothing or hair. For still photos the green shows up and ruins the images. You can get rid of the green in Photoshop but it is a lot of work. There are special green screen software programs that can do a pretty good job quickly but you have to spend extra money for them.
The seminar advice was right. Use a white or gray background and you can do extractions easily right in Photoshop - but you must get your lighting right.
How to do seamless white is widely misunderstood. To get a good image that is easy to separate and composite you can NOT overexpose the background too much and you need to keep the subject away from the background.
Zack Arias has one of the best tutorials available on seamless white. Just remember that the closer your subject is to the background the less you can overexpose the background or you will get light reflecting from the background and causing the edges of the subject to be overexposed - apparently what is happening to you now.
Here are some easy to follow guidelines.
Use a flash meter to make sure all your exposures are correct. Getting the background evenly lit is critical. Getting the background exposure vs the subject exposure is also critical.
With a 6' subject to background separation keep the background to no more than one stop of overexposure.
With a 10' to 12' subject to background separation keep the background to no more than 1.5 stop of overexposure.
Living and loving it in Bangkok, Thailand. Canon 7D - See the gear list for the rest.