For those of you too young to know about film, let me tell you it’s nasty, and you should stay away from it. Some of us, however, have images captured on film that are worthy cleaning up for the digital age. Here we’ll deal with the three most common problems: dust, color shifts, and grain. It’s painstaking work, but those old photos can’t be replaced, and modern digital tools help a lot.
The first thing to do is to get the film scanned into a digital file. Doing it yourself requires an expensive scanner and patience. Mastering that art may be worthwhile if you intend to digitize, say, more than a couple hundred old negatives and slides. I used a commercial service. A resolution of about 1200 pixels per inch of film seems about the minimum, and many people say that 1600 or more is needed for fine-grained film. It should be fine enough to show the original film grain.
I have negatives I took in 1999 with a Noblex panoramic camera. (A later, similar, model is reviewed here) The negatives are about 2” x 5”, which scanned to make a roughly 2400 × 6000 pixel image. I used Fuji Velvia 100 film. Velvia is an ultra-high color saturation film, and it is still available.
The photo was taken from Sand City, looking across to the city of Monterey, California. I hand held the Noblex camera. That takes a little practice, because you have to check the levels to make sure the horizon is level and centered. The film is wrapped around a cylinder and scanned by the moving lens, so a small tilt produces significant distortion. The big advantage over spliced panoramas is that the continuous image captures action without the problems of splicing across boundaries. In this panorama the birds were moving continually.
I had the negatives digitized well before the colors shifted. However, the film processor screwed up the processing so that the originals had a distinct magenta tint. They say, “Sorry, we’ll give you a fresh roll of film.” Old film tends to lose green. The magenta tint will serve well to demonstrate the general correction method.
Photoshop Elements© has a Remove Color Tint feature. That works well for odd lighting like fluorescents, but it doesn’t work well for film problems. The film is in layers, so two of the three layers maybe in good shape. A color that has little of the errant layer not need much change, while other colors may need a lot. Remove tint doesn’t handle that well.
Instead, access the_ Enhance > Lighting > Levels_ and pull down RGB to access the individual red, green, and blue components. Here is my original panorama with the red histogram for my photo:

Pushing the center mark of the histogram to the right reduces the amount of red in the image. The sky has the tint, so adjusting red can restore the sky to blue.

The sky is blue, but the sand acquired a green tint. Did I mention that film layers interact? The solution is to select the whole sky. I used the selection box tool to get most everything above the horizon, then Select > Feature with 100 pixels to smooth the transition. Now the red histogram allows the tint of the sky to be adjusted without affecting the sand.

Next, let’s talk about dust. Scanning services combine air blasts and electrostatic brushes to get rid of as much dust as possible, but I can guarantee there will still be dust spots in the digitized image. To hold the large negative flat, they pressed in between two glass plates, so both sides of the negative and both sides of two pieces of glass are available to hold dust. You have to retouch out the spots.
In Photoshop, View the image with Actual pixels, then enlarge it once or twice more. Only a small portion of the image will be visible at one time. Start in one corner of the image and work across to the other edge, checking for and removing the dust spots. Then step the view down and work across another band, slightly overlapping the first.
Here are a couple of highly magnified dust spots. Trust me, those are not meteors or flying saucers. There were about two dozen in total on the scan. Starting with a negative, the dust appears white.

The tool for removing the spots is the Healing Brush, obtained by right clicking the bandage icon.

Position the cursor over the spot an press the left mouse button. If necessary, stroke over the area, as in the example at left below.

Releasing the mouse button fills in the area selected with the brush. It does a nice job of matching the background across the spot. (It works on power lines too.)

We are on the home stretch now. Tools for removing noise are quite good, and digital cameras have noise in low light exposures. The noise reduction works on film grain just as well. There is a de-noise filter built into Photoshop, but I used the Topaz Labs DeNoise filter.
Here is the bird in the sky enlarged, before noise reduction.

And after noise reduction,

I used the lightest level of noise reduction.
I did some cropping to get rid of my shadow in the lower right corner. With a 150 degree field-of-view, that can be a problem. The final image is then:

It’s better viewed in the large version The saturated Velvia colors survive.
Now you know why film is nasty.