Holga Four Color Filter Set for Color or Black & White Film.

These color filters are fun to enhance your color photos, blue makes water and the sky look really blue for example. For pictures taken at night, the filters have a dramatic effect. I like them!

I wish they had this system for every camera that I use. It lets you use square filters, or you can cut your own out of plastic, glass, or overhead projector transparency material. The most useful of the filters in this kit is the yellow filter, which warms up a scene quite nicely.