Red Filters (Black and White Photography)
In landscape photography, a read filter will turn a Blue sky almost Black and clouds really stand out, giving the scene a dramatic feel. They’re also excellent for increasing visibility in haze and fog.
When shooting plants they help increase definition between flowers and foliage. This is particularly useful when shooting Red flowers, as they have similar tone to the surrounding leaves.
Red filters produce such an extreme effect that they can make your photo look like it’s been shot through an infrared filter. Thus makes them a popular, cheaper alternative to true infrared photography.