Rainbows are somewhat of a cliché in landscape photography. However, it is undeniable how they can add interest to the scene that would otherwise be drab and perhaps boring.
Sometimes in photos they will look washed out and uninteresting- a poor representation of what you can see before you. Thankfully, there is a very easy way this can be remedied. This is through use of a circular polarising filter (CPL).
You might think that as a CPL is usually used to cut out polarised light and that rainbows consist of some degree of polarised light that using a CPL to photograph rainbows is a bad idea. However if you’ve never tried experimenting with CPLs and rainbow photography then next time you see one give it a go.