Photoshop makes a variety of tools available to you--like curves, levels, dodge, burn, etc.--for adjusting old photographs and the resources below will help you get a start on this kind of topic.
quote:If you ever find a scratch on your image, make a generic selection of
that area and apply one of the following filters: For a scratch that
is darker than its surroundings, try Filter>Other>Maximum (this
sometimes also works for stubble on someone's face). For one that is
brighter than its surroundings, try Filter>Other>Minimum.
If you have any specks on your image, first try
Filter>Noise>Despeckle. It's that's not aggressive enough, then try
Filter>Noise>Median.
If you feel like using the Dust and Scratches Filter, then start with
the Radius and Threshold settings at their lowest settings. The
general idea is to increase the Radius until you find the lowest
setting that will rid your image of the dust or scratches. But since
that makes you're whole image look blurry, you'll want to bring the
Threshold setting way up and then slowly lower it until you find the
highest setting that still gets rid of the dust and scratches in your
image. The only problem is that this filter has the nasty tendency of
thinking that eyelashes and other important content are scratches. So,
right after you apply that filter, go back with the History brush
(it's right below the paintbrush tool) and paint back any important
detail that Dust and Scratches screwed up.
If the Dodge and Burn tools don't quite work the way you'd like them
to, then try this instead: Create a new layer, change the pop-up menu
at the top of the Layers palette from normal to Color Dodge or Color
Burn and then paint with a shade of gray. Color Dodge will brighten
your image, while Color Burn will darken it.
If you ever encounter a color moire pattern when scanning patterned
fabrics, try choosing Filter>Blur>Gaussian Blur and use a setting high
enough to blend the majority of the moire pattern into the image
(don't worry if the image looks overly blurry). Then, to get that to
just affect the colors, choose Edit>Fade Gaussian Blur and set the
pop-up menu to Color. Since the majority of the detail is held in the
brightness of the image, that should make the moire blend in while
preserving most of the detail. If there are still a few areas where
the moire shows up, then grab the Paintbrush tool and set its blending
mode to color. Then, Option-click (Mac), or Alt-click (Win) on an area
that does not contain the moire pattern and is representative of what
the area with the moire should look like and then paint over the moire
pattern. If the moire is more of a brightness change instead of a
color one, then you'd have to go through a more involved process that
includes copying a channel, adjusting it, and then turning that into a
selection and using it to adjust your image. But that's something I'd
cover in my new CD series, if someone were to send me a good example
image (hint hint... check out www.digitalmastery.com/submit for
details).
Finally, if you ever select an area and blur it to make it look out of
focus, you might want to take steps to insure that that area doesn't
look posterized when you print it. I usually just choose
Filter>Noise>Add Noise, set the Amount to 3, the Distribute to
Gaussian and turn on the Monochromatic checkbox. The most important
setting is the amount, the other two do rather subtle things when you
have the amount set that low, so don't stress if you don't remember
every setting that I use.