Q. Can color sildes be salvaged after they have been water-damaged in a fire? A. It depends on their condition. You could have kept damage to a minimum if you didn't allow the slides to dry. For future reference, keep film in original enclosures -- mounts, envelopes, sleeves and so forth.

The best way to do this is to immerse slides, with mounts, in cold water -- about 69*f. -- containing a half-ounce of formaldehyde per quart of water. The solution will prevent the gelatin emulsion from swelling and softening -- the major causes of damage -- and will stop bacteria from growing. sAs soon as possible, carefully separate the films from their enclosures and wash the films for 15 minutes in water 68* or lower.

If necessary the films can be swabbed, but extreme care should be taken because the emulsion is very susceptible to damage. Try to avoid sudden changes in the wash waters. After washing, rinse negatives or transparencies for one minute in diluted Kodak Photo-Flo solution. Q. What color film is best to use under fluorescent lighting -- slide or Kodacolor? A. Taking pictures under fluorescent lighting is a problem, because lamps vary in color and brightness, depending on brand and age. Fluorescent lamps also change color as they warm up: turn them on for at least 10 minutes before taking pictures.

I prefer Kodacolor 400 (print film) when shooting under fluorescent lights.

Daylight color film should be shot with an FLD filter, and an FLB filter should be used with tungsten film. Remember, you lose one full f-stop with these filters. Q. I'm interested in aerial photogaphy. Can you advise me on the camera lenses and settings that are best for this type of photography? A. I consider a standard lens such as the 50mm best for aerial photography. A wide-angle lens could lead to distortion, but it all depends on the effect you are looking for. For example, if I plan to take a picture of the skyline. I would choose the 50mm and make sure that the pilot maneuvers the plane in a position best for photos. When taking pictures from a plane, grasp the camera firmly and don't rest it on the window or any part of the plane: the vibration ruins pictures. A clear and sunny day is best, and I prefer noontime. Anywhere from 1/500th of a second to 1/1,000th would be fine for the shutter speed. The aperture depends on the type of film you'll use. For good pictures the sun should be on a 45-degree angle. oIf the sun is directly on the area, the pictures will be flat. Set the camera lens at infinity.

For those who would just like to take a few snapshots while traveling via commercial airlines, here are a few tips. If you have an Instamatic camera, use it, because I've seen some fairly good shots taken with inexpensive cameras. When you arrive at the boarding area, try to get assigned to a window seat. The best spots are the front or back: avoid the wing. If the plane is flying east, ask for a seat on the left side; if bound west, sit on the right side. Hold the camera an inch from the glass to avoid reflections.