Q.

I am interested in purchasing filters for enhancing and correcting colors in daylight films. After some research, I am confused as to what types to use.

I know a yellow filter, for example, will reduce excessive blues. But can that same yellow filter, or any yellow filter for that matter, be used to enhance yellows?

Also, what is the difference between correction, compensating, conversion and light balancing. They sound as if they all do the same thing!

A.

The use of filters is one of the most difficult and yet most rewarding things in photography. It takes careful thinking and lots of practice.

First, a yellow filter will indeed reduce blues if you are dealing with black-and-white film.

As to the rest of the question, let's talk filtering color film.

Thanks to Ira Tiffin, vice-president of the Tiffin Manufacturing Corp., whose name has been synonymous with photographic filters for 50 years, for some new information on this subject.

Correction filters (usually called CC filters) are used to correct existing color. You do this by introducing a filter between your subject and film so that the film "sees" that subject differently.

For instance: If you are dealing with an overcast day, a yellow filter can brighten the scene. This is not for a dramatic special effect, but a simple enhancement and correction.

If you are photographing a fine art print and realize that the room lights will make the shot too orange, a correction filter can restore normal balance.

Fluorescent lights may be causing too green a print. A CC filter can knock back the green.

Correction filters are often used in very technical or scientific situations. Different batches of the same type of film may need CC filters to remain constant.

Conversion filters are used to change from one particular kind of light to another to suit a specific kind of film.

The best example is using a conversion filter to be able to shoot tungsten film outdoors or outdoor film under tungsten light. Several people I know use mostly outdoor film but carry a conversion filter for indoors.

Compensating filters are similar to correction filters in that they help adjust the light seen by the film.

Light balancing filters are similar to conversion filters.

Polarizing filters are used to enhance color and areas of a photograph and to reduce or eliminate reflections off glass or other shiny surfaces.

Other filters are used for special effects. There are fog, diffusion and starburst filters. There is a filter to give you a sepia tone that comes in several densities for more or less tone. There is the FLD filter used to correct fluorescent lighting that gives a great effect for sunsets. The 25A red filter can create heat effects, such as sun on the beach pictures. The 47 filter is blue and is great to add cold to snow scenes. It also makes for dramatic moonlight shots.

Remember, it's better to use slide film when you're experimenting with special-effects filters. You'll be able to see the results directly, without trusting to the whim of an electronic printing device to show the colors you've tried for.

Last week I visited the Snap Shot Store at Montgomery Mall to see something new.

It's called Photovision and was the first installation of its kind in this country.

It's a free-standing portrait booth, roomy -- big enough for a family of five -- comfortable and allows you to pose yourself for a set of pictures.

You sit on one side of the booth (painted all black for a neutral background) and face the lens. The great gimmick is that you set up your own portrait!

There's a television set built into the wall below the lens and you see on the screen just what the lens sees. You hold a remote-control unit, which allows you to zoom in andout for various poses. There are modeling lights so you can tell just how the booth's strobes will work. When you have the exact lighting and pose you want, you fire the camera and take your own picture.

I made some tight closeups of myself, then zoomed back to make some waist-up shots. I even made a couple of me talking to the stuffed dog that had been left in the booth.

I was delighted with the results.

Photovision uses a Maxxum 7000 and print film. When your shooting session is over, the Snapshot attendant removes the film, sends it off for processing and your 3x5 prints are ready the next day.

The cost is $10 for 12 pictures, and you get the negatives.

No appointment is necessary, and no one rushed me once I entered the booth. It all was great fun!

Carl Kramer deals with questions of general interest but cannot respond individually. Address him c/o Weekend, 1150 15th St. NW, Washington, D.C. 20071.