The Self Portrait Challenge theme for April is:
High Key // Low Key
I, along with the rest of the group, are exploring what these terms mean and how to accomplish them photographically.
Briefly, your 'key light' is your main light. This might be sunlight or a studio strobe or a candle, but it is the light that is providing the main light to any photograph.
So, High Key would be exposing so that you're getting more of this light than you would for a 'normal' exposure. High key photos will generally be dominated by light tones and highlights.
Conversely, Low Key would be exposing so that you're getting less of this light than you would for a 'normal' exposure. Low key photos will generally be dominated by dark tones and shadows.
Obviously, my first attempt is meant to be Low Key.