introduces a new problem which requires very careful consideration.
If you had three red apples of a bright and more or less uniform colour and shape and placed them one on the near end of a form, one in the centre, and one at the far end, and you took up your pencil and drew the light and shade of the three apples, would you draw each apple with the same degree of light and shade?
Would you not give the near apple more distinct light and shade, more accent, more strength than the apple farthest away? Of course you would! Even if you drew without thought you would instinctively draw something a good distance away in a broader and simpler manner.
For the sake of argument let us presume that we are painting a picture representing three ladies in black velvet. One in the foreground, another in the middle distance, and a third in the far distance. If we painted the black velvet dress in the far distance as richly, as strongly, as definitely as the black velvet dress in the foreground, we should paint an untruth.
Things in the extreme distance must not be as strongly depicted as those in the foreground or middle distance, as I demonstrated when stating the first rule of perspective.
If we draw or paint a picture of a street with its diminishing houses, railings, lights, pavements, drawn correctly in perspective, but ignore the air that intervenes and blots details from view, then we shall draw something that is not true to Nature.
The policeman on his beat at the end of the street is merely a dark uniformed figure; as he approaches we note that he wears a high helmet; nearer still, we see his silver badges and buttons and shiny boots; as he passes under our window
