Colours deeply effect our emotions. Different colours and combinations of colours, produce a different emotional response from us, or in us. As a photographer, it's important to use this knowledge in your work! Ultimately, the style of a photographer working in colour develops and becomes individually recognisable because of his/her own responses to colour.
We know that cool colours (blues, greens) can have a calming effect of highly strung people while at the same time having a depressing effect of people of a depressive nature. Hot colours (reds, yellows, oranges) have a stimulating, positive effect on laid-back people, but can sometimes prove too stimulating and heighten tension in more highly strung or even violent people.
The contrast and density of the colours in your images will be considerably affected by exposure. Underexposure produces saturated colours and high contrast, while Overexposure produces washed-out colours and soft contrast.
Steve McCurrry is a famous photographer who's images are recognisable by his use of warm & bright but muted colours. Here are a few examples:
When you are setting up a portrait or still-life pictures, it's important to be aware that every colour you introduce will influence the mood of your photograph.
The only way to learn what your end results could be, is to experiment with background and colour combinations to see what moods you can create!
Colours can be used to convey a feeling almost regardless of your subject matter.