Warm-up Filters
Warm up filters can be used for technical purposes, colour temperature correction from daylight to tungsten light sources for example, or for effect in landscape photography.
A warm up filter can work wonders for an image, boosting colours or just adding a pleasing warmth that may not be present naturally. The trick is not to overdo it, and a little warmth is often all that is needed to make the difference. Generally available in both graduated and standard types.