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BOOT CAMP 200 (08/11/01)
PICTURE EDITING, part 1
If the cost of digital still cameras (DSCs) falls much
further they'll be paying us to take them away… Well, maybe not just yet but it
is fair to say there are some very decent models currently selling for less than
£200, and the picture performance of some mid-range DSCs now compares very
favourably with compact 35mm and APS cameras.
However, taking pictures is only the beginning, it's what you
do with the images afterwards that makes this technology so interesting. Once your pictures have been downloaded onto
your PC's hard drive there's almost no limit what you can do to them, from
relatively mundane things like cancelling 'red-eye' to inserting or removing
people and objects, changing facial expressions and applying a range of exotic
special effects and filters that are simply not available in conventional film
photography.
Over the next three weeks we'll be looking at how you can
make the camera lie, and lie convincingly, using some simple tricks and the kind
of picture editing software that comes with most digital still cameras, and the
many budget and mid-market photo editing programs now available. Incidentally,
the Paint program included with Windows has some useful facilities but it's not
really up to serious picture work moreover some earlier versions, included with
Windows 95 and 98 cannot handle common digital still camera picture file formats
like JPEG and TIFF. For more information about picture formats, managing your
files and image sizing have a look at Boot Camps 187, 188 and 189.
We'll start with some very basic techniques to prepare your
pictures for more in depth editing. The first one is image rotation; pictures
taken on a digital still camera are rectangular in shape so it's quite natural
to turn the camera sideways to frame a tall object or structure. Obviously it's
not a problem with pictures taken on a conventional film camera, when the print
comes back from processing you simply turn it around, however you can't easily
do that with a PC screen so the first thing you need to do after downloading
images to your computer is turn the sideways shots the right way around and
re-save them.
Virtually all photo-editing programs have a rotate facility
that turns the picture right or left 90 degrees at a time, however, some
programs also have a Free Rotate option that lets you rotate the image in
one-degree increments. This can be handy if, for example, you were leaning to
one side when you took the picture. Alternatively you might want to deliberately
tilt the image for effect, to emphasise the angle of a slope, or make it appear
as though your subjects are on a hill or climbing a mountain.
The problem with free rotation is that once the image is
saved the sides will no longer be parallel with the screen, and that's one of
the many things our next editing technique can fix. Cropping is one of the most
useful tools in any photo-editing program, it can instantly transform a dull
looking image and cut out all sorts of little embarrassments, as well as help to
straighten up wonky edges.
Most of us never get close enough to our subjects, especially
when taking pictures outdoors and unless your camera has a zoom lens – and you
remember to use it -- you end up with little people in the near distance set
against a huge expanse of background. Cropping can also help when the subject
isn't in the centre of the frame, there's too much sky, or you can remove
someone or something you don't want in the picture.
Some programs have specific 'Cropping' tools, others have
'Selection' or 'Marquee' functions, but in most cases, after the tool has been
selected, the mouse cursor turns into a crosshair which you place in the top
left hand corner of the area you want to select; click and hold the mouse button
and drag it to the bottom right corner of the area. When the mouse button is
released the defined area is normally shown bordered by a dotted line. The size
and shape of the area can then be adjusted using sizing 'handles', bearing in
mind that as you 'enlarge' a part of an image you reduce the amount of detail it
contains.
When you are happy with it save that as a new image. Don't
give it the same name as the original picture file otherwise it will be
overwritten, and you won’t be able to use it again. Instead just add a '1' to the end of the filename (before the
extension, i.e. seaside.jpg becomes seaside1.jpg), so they'll appear next to one
another in your directory listings.
On some photo editing programs you can speed things up by
using keyboard shortcuts, standard Windows Copy and Paste conventions often
work. For example, select the area with the cropping/selection tool then press
Ctrl + C to copy it to the clipboard, then Ctrl + V to paste the new image back
onto the program's desktop.
Next week – Part 2, Colour Brightness and Contrast
JARGON FILTER
JPEG
Joint Photographic Experts Group (part of the International
Standards Organisation), 'lossy' image file format used by digital still
cameras, etc., where data is compressed to reduce file size but without unduly
affecting picture quality
RED-EYE
Demonic effect, giving people (and animals) bright red (or
green) pupils, caused by camera flash reflecting back from the subject's
retina
TIFF
Tagged Image Format File -- lossless 'bitmapped' picture file
format that describes in detail the attributes of each pixel in a digital image
TOP TIP
As you know email worms like Kak, the Love Bug and SirCam
spread by attaching themselves to emails, which are sent out automatically to
contacts in your Outlook Express address book. Obviously the first line of
defence is to exercise caution when opening attachments and to make sure that
your virus scanner is kept up to date but occasionally these infections spread
so quickly that the updates can take several days to be distributed.
Here's an idea that could help stop the next 'mass emailer'
virus in its tracks. The idea is that if your PC gets infected it will start
sending mail – if the 'Send Messages
Immediately' is enabled (Tools > Options, Send tab) -- but if you create a
deliberately erroneous address Outlook Express should stop sending and display
an error message and you'll be warned that something is amiss. The address in
question needs to be the first entry in the contacts list, so open Address Book,
click New, then New Contact and in the First Name box type 'AAAAAA' or '00000'
without the quotes or any '@' sign and click OK. Lets just hope you never need
it…
NEXT
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