Nicholas Skinner

Freelance website and web application developer

Archive for September, 2008

Chroma Key Photography

Sunday, September 14th, 2008

Table with Blue Screen Cloth BackgroundI was recently asked to assist in taking a “professional looking” photograph of a handmade piece of furniture.  Since an situ photograph was not possible it was decided to use a Chromakey blue piece of fabric which would be replaced by a solid colour background in Photoshop CS2.

For the first few attempts we did not pay any attention to lighting. The result was that the blue fabric could not be easily fully removed in Photoshop, as the dark shadows meant the blue turned to black.  We then tried number of things to remove the shadows however not having any kind of professional lighting equipment this was not possible in the room we were using.

In the end the unexpected solution was to remove nearly all light from the room, and then just set a long exposure time. This resulted in no major shadows, and therefore a consistently coloured blue background that could easily be removed.

Table with White BackgroundTo remove the background in Photoshop I used the “Color Range” tool with ~100 “fuzziness” clicking multiple times in different areas of blue in the picture.

After manually removing an unfortunate reflection in the glass on top, then adding a 2 pixel feather the end result came out looking very respectable / much better than I had been expecting.