Hey, light it up through this tutorial!
It talks about how the different types of keys define the overall tone of the final portrait. There’s three different kind of keys: low, middle, and high. To identify the key of a portrait you can determine the average tone for the scene.
Each key has it’s way of functioning: low key is created by using a dark background and dark clothing and props-it has more dark elements than bright ones. The shoot may be shot with a higher ratio as contrast is acceptable due to the drama of a lower tone.
Middle key is the set tone that is in the middle of high and low. The way you can set this tone is by using skin tone and clothing may be used to accent the tone of the skin with contrast rather than allowing all elements to blend together.
High key is setup completely differently. It requires more lighting, power and equipment! Aside that, it also requires a great deal of light control and has the most risk of overexposure and could possibly lose details around the portrait, which is something we don’t want! So, the background of this portrait is paper because it is slightly overexposed which results in a pure white seamless background. Also, if a model is involved, it is best for them to wear bright clothing.