Archived from groups: rec.video.desktop (
More info?)
<reader@newsguy.com> wrote in message news:umzwjb5af.fsf@newsguy.com...
> Scanner = Epson 4870
> Just wondering if there is any advantage in scanning photos in higher
> res than the default (on my setup) 150?
>
> This would be for further editing/fixing.
>
In video we don't talk much about dots per inch. For that measurement
to mean anything, you would have to know how your viewer's screen
was going to be. Even then, the number isn't going to be all that useful.
What you concern yourself with in video is the resolution, and the aspect
ratio of the medium. We speak of them as pixels.
NTSC video is most often 720 x 480 (although the official standard calls
for 486 lines of video instead of 480). So, the 480 part is fixed because
every NTSC TV has that many lines (sort of). The aspect ratio the 4:3,
and if you multiply that out you get 640 x 480. Woops! 640 is not 720.
That is because the pixels become rectangular because of the increased
resolution. 640 was very common for a long time, but it always looked a
soft.
The number of lines is fixed, but you can play with the horizontal
resolution.
It is common to prepare graphics for video at 720 x 540 to get to a number
that gives square pixels to work with. This is because pixels on a computer
are square. I tend to resize the finished graphic to 720 x 480 as the last
thing I do before saving the version to be used in video.
That's the background.
You can scan at whatever size you want, but it is the pixels you are
interested
in, not the DPI. if the frame is to be a still, you could just set up your
image so
the output of the scanner is 720 x 540. I usually use something that
approximately
doubles that number.
I always go through a paint program anyway, so I'm going to be scaling the
image anyway. I also do some color improvements and such, then I crop
to eliminate unwanted elements.
Once the image is the way you want it to look, you scale the image to fit
video.
You want to turn on "constrain proportions" and scale to either 720 wide, OR
540 high. Let the software come up with the other number. You will usually
find
that you either need to crop a little more or add to the image to get the
other dimension. What ever you need to do to get to 720 x 540 without
further
scaling.
If you had a picture you needed to use that was a very wide panorama of
New York City but it's not very high. Your cropped version is 2000 pixels
wide and 500 high. You have 3 choices.
1) Scale the width to 720, and you have a picture that isn't tall enough to
fit
the frame. In Photoshop, you could alter the canvas size to be 540 high, and
PS will put bands of your current background color above and below the image
to fill it out to 720 x 540. But you don't like the bands. Hit undo a few
times.
2) Scale the height to 540 and you now have a picture that is way too big.
you'll have to crop out part of the image to make it fit into 720 x 540.
3) The remaining option is to bring the image into your editing program as
is,
and do a move on the image (requires more rendering that a pre-sized still).
If you want to do a move, then your image wants to be larger than 720 x 540.
Guesstimate how far in you need to zoom for the tightest shot, and then
digitize
your image so that the part of the image to be used for the "close-up" is at
least 720 x 540. If you had an image that was 1440 x 540, you could do a
pan from one end to the other. if you had an image what was 2000 X 1500,
you would have room to zoom in quite a bit from the widest shot. If you are
going to do moves, then your image should stay as square pixels and just
let the editing software do all of the scaling.
David
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