Black & white over colored technique

Anyone here knows how to this effect in Final Cut Pro 4.5? I saw a commercial which is black & white & the only colored is the product endorsed. How can I do that here in Final Cut Pro?

Another question that pops up on the regular...

[www.lafcpug.org]

Thanks for the reply. What I want to know is how can I apply it in moving, not in stills. Does it have to be always in plain background?

> Does it have to be always in plain background?

No. Limit Effect in Color Corrector targets colours, not shapes. However, it's much more difficult to apply this technique if the backgrounds you want to desaturate share the same colours as the objects you're retaining in colour. In that case, you may want to combine this colour-limiting effect with a travelling matte.

applying traveling mattes can be a VERY complex task if your object changes much in contour and perspective over the duration of the clip...

>>What I want to know is how can I apply it in moving, not in stills<<

The technique Derek linked to works for moving images as well as stills.

> applying traveling mattes can be a VERY complex task if your object changes
> much in contour and perspective over the duration of the clip...

Very true. However, I think if you can get the Limit Effect working, you can apply a broad, tracking matte which keeps the colour effect within a certain set of borders, to "ring out" other parts of the shot that have the same colour, kind of like this:

____________________________
| STRAIGHT DESATURATION |
| |
| __soft matte_ |
| | LIMIT | |
| | EFFECT | |
| |__________| |
| |
| |
|___________________________|

The diagram got a little *&^%ed up, but hopefully the idea comes across!

I've done this semi-successfully very quickly with a travelling matte. If you have time, you can make it work.

Product containters have simple shapes so it would not be too much of a nightmare to roto. You need to do this work in Motion, Boris RED or AE though.



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can you teach me how to do this in Motion or in after effects pls. Thanks.