12/13/2003
6:20:24 PM | Setting the image's contrast is like using contrast filters
in the darkroom when making prints. Contrast is the relative
difference between the darkest parts of the image and the lightest.
There are many different ways to set contrast and they all have their
own advantages.
The easiest way to set contrast is to use the Brightness Contrast
option. Play around with it to see how it works.
Another more powerful technique is to use the Levels option. This
shows you a graph of how much of each brightness is used in your
image. (think of it like a stereo equalizer)
In this example there isn't any black below a certain point, or white
above a certain point. This is way most prints and negatives will scan.
You can get a better looking image by adjusting the sliders to eliminate
the unused color values. Be careful as this may add some noise to your
photo...(usually the increased contrast makes up for the lowered quality)
This tool is more powerful than simply using Brightness Contrast because
you can control the upper and lower limits separately...AND you can even
adjust the midpoint.
The next two tools are really cool. They are called Dodge and burn after
the darkroom techniques. It refers to brightening a section of an image
or darkening it. This is a great tool to adjust the contrast on a region
or single area.
Dodging looks like a black circle on the end of a stick. In the dark room
it is used to create a shadow over an area that is to be "burned less" by
light while printing.
Choose a brush size and "paint" an area lighter.
You may want to change the exposure level to something pretty low or the
edges of the adjusted area will be too abrupt. It is better to make many
passes and watch the image evolve rather than do it in one pass.
The other tool, burn, is the opposite of dodging. It looks like two hands
making an empty circle. In the darkroom this would be used to expose a
single area of a print more effectively making it darker. Otherwise it
works the same way as dodging.
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