Sentence:  First I make preliminary watercolor sketches in quarter scale ( approximately * * f inches ) in which I pay particular attention to the design principles of three simple values - the lightest light , the middle tone , and the darkest dark - by reducing the forms of my <WSD>subject</WSD> to these large patterns . 
Meaning of the word marked with <WSD> tags:  something (a person or object or scene) selected by an artist or photographer for graphic representation