A filter lightens its own color and darkens the color of complementary color in the final print .for e.g. a yellow filter used in black and white photography will darken the blue sky which is its complementary color and will thus ultimately help in increase the contrast in the print.

Filter is a glass or a gelatin material, which limits the amount of a particular wavelength of light reaching the film.

A filter lightens its own color and darkens the color of complementary color in the final print .for e.g. a yellow filter used in black and white photography will darken the blue sky which is its complementary color and will thus ultimately help in increase the contrast in the print.

Filters are available in circular as well as square shapes .A circular filter fits to the lens directly and there is a filter of each filter size of lens. The disadvantage here is that if we have 5 different lenses of different filter size we will have to buy 5 sets of filter to fit each lens.

Then there are square filters like cokin and lee filter systems, in which the filters fit in an adapter, which in turn is fitted to the lens with a ring .so we just need to buy ring to fit the adopter for each lens of different filter size.

Every filter has a filter factor associated with it, which is the amount of light it cuts down. A yellow filter cuts down light by nearly ½ to 1 stop depending upon its intensity and thus has a filter factor of ½ or 1 A polarizer filter has a filter factor of 1-2 stops depending upon the amount of polarization we are using.

There are filters for B&W as will colors films and some of them can be used for both of them
The colored filters used in photography are as follows----

1. YELLOW FILTER----Yellow filter cuts down the haze and increases the blue of sky, which in turn increases the final contrast of the print.

2. RED FILTER----This filter increases the contrast to extreme and the sky turns nearly black in day light situation.

3. ORANGE FILTER----This also increase the contrast but to a greater extent as compared to yellow filter.

4. BLUE FILTER-80 SERIES-----This filter is used to cut down the yellow of tungsten light in indoor situations, so that we get exact color of subject in the print otherwise we will get a yellow cast over the print.

5. AMBER FILTERS-85 SERIES FILTERS----these filters are used when we want to raise the color temperature of the film for e.g.: 85a is used when we want to raise the color temperature of the film from 3400 degrees to 5500 degrees or we can say that when we have a tungsten balanced film and we want to use that film in day light then this filter is used.

6. MAGENTA FILTER----This filter is used to cut the green cast of fluorescent light, which is commonly used in households.

Then there are specialized filters

1. UV FILTERS ---- These filters are used to cut the ultra violet radiations of the sunlight and is generally kept over the lens permanetaly.it doesn’t have any filter factor.

2. SKYLIGHT FILTERS ---- This filter also cuts down ultra violet radiations but has a added advantage, when we are at heights it cuts down extra blue of light which generally results in blue cast over the print or slide. This filter also doesn’t have any filter factor, so it’s better to use a skylight filter than a uv filter and can be kept over the lens all the time.

3. POLARIZER FILTER ----This filter is generally used to cut the reflections associated with reflective surfaces and also cuts down the reflection of sunlight and we get deep rich blue sky by using this filter. This filter has two discs by turning which we get different darkness of the sky. A polarizer gives maximum effect when the camera position and the light source is 90 degrees to each other and decreases gradually. This filter has a filter factor of 1-2 stops depending on the polarization we are using and is must for every serious photographer.

4. NEUTRAL DENSITY FILTERS ---- These are used to cut down the amount of light reaching the film when the light too much to come in our shutter –aperture combination. These are available in differently intensities like 1,2 3 stops.

5. DIFFUSERS----These are also commonly used filters to diffuse the subject normally young women and children’s to give a soft effect to the photograph.

Then there are many SPECIAL EFFECT FILTERS available like STAR FILTER to get the star like effect of lamps lighting up in the frame.

A very commonly used filter used by professionals and amateurs likely is the GRADUATED FILTERS .in these filters the upper portion is like a normal filter and the effect of the filter keeps on reducing as we gradually move down and these filters are very useful in many situations .for e.g.: a graduated nd filter is used when in broad daylight the sky is nearly white and we want to cut the light from the sky so that the difference in expose above and below the horizon decreases then we use this filter . Also graduated orange filter is used sometimes at the sunset time to make the sky a little more orange.

This article is written by Ashish from Professional Commercial Photographer India