A low contrast filter, as the name implies, will reduce the over all color contrast in your motion film or digital video image. The low contrast filter is found in varying intensities in accordance with different amount of color contrast reduction you may want done to the motion film or digital video image.
You can expect the low contrast filter to make serious alterations to all parts of the image, but especially darker locations with shadows. It does this by taking highlights and giving them representation in these areas of shadow. The low contrast filter will make every single color have a softer look instead of having sharp opposition to each other.
You are going to find that there are many different names and variants of the low contrast filter, but it is important to look at exactly how much the colors are made less saturated in the over all image. Before actually buying the low contrast filter make sure that you actually see how it looks.