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Posted by Specs on 01/12/06 15:24
"Richard Crowley" <rcrowley@xpr7t.net> wrote in message
news:11scpd4h5rad7c7@corp.supernews.com...
> "Wondering_1" wrote ...
> > Can anyone tell me which software does the following:
> >
> > 1. Still image, appearing in 3-D, as the foreground moves
> > at a different speed than the background when panning, of
> > the foreground zooms in as the background remains still.
> > Somehow, the foreground has been lifted from the image,
> > slightly magnified to cover the original, then animated...
> > I think it's soo cool, but haven't been able to find out how.
>
> I've seen it done two ways...
> a) Zoom the camera lens while moving the camera so that
> the background remains "constant" while the foreground
> object grows larger. This is tricky to get just right and
> there is a name for it which excapes me. ("regrograde zoom"
> or something?)
>
I don't think he was asking about a "trombone". I think you are on the
right track with b) below.
> b) I've seen some archival photos (old black & white stills
> from some news archive) where they used Photoshop, etc.
> to cut out the foreground image, and impose it onto a
> separate background. By moving the foreground and back-
> ground at different rates, you get a 3D effect. The tricky
> part of this is to get a continuous background image
> because of course it is missing in the original where the
> foreground object occludes it. Sometimes it may be
> "recreated" by an artist, or maybe they select a similar
> whole image and substitute it for the original background(?)
>
Quite correct. What a lot of people overlook with these 3D still image pans
is that the layers do not have to be from the same image. In fact most of
the examples with dramatic virtual camera moves are nothing more than
composite pictures. Filling in the gap left in the background when a
foreground object is removed can be done quite easily with Photoshop or
combustion's Clone Brush. It tends to get quite difficult when the
foreground object is quite large or the background is busy hence the use of
"fake" or composited backgrounds. Call it a trick of the trade or even
pulling the wool over the viewer's eyes if you like....
> > 2. Video images where everything is black and white
> > except some roses that are red...how is the color turned
> > off selectively?
>
> The trick here is the either incredibly tedious handtracing
> of each frame (to separate the color part from the mono-
> chrome part), or some very specialized (and expensive)
> software which automatically tracks the selected objects.
>
> What you need is called a "traveling matte" which is
> used to mask the color or monochrome part of the picture.
> It is a simple "silhouette" of the color object, but a different
> one *for each frame of video/film*.
Another way to achieve this at least in Avid which I use is detailed on this
web-site. It works very well and can be modified for other NLE users.
http://www.geniusdv.com/avid-pleasantville.php
Alternatively ensure your NLE has good secondary colour correction tools
(unlike Avid Xpress Pro!!!) and the Pleasantville effect is a doddle...
Hope that helps
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