The difference between the lightest and darkest areas of an image. High contrasts would be black on yellow and black on white.
The difference of tonal gradation between light and dark values within an image. A high-contrast image is predominantly highlights and shadows with few gray tones. A low-contrast image has few highlights and shadows with predominantly even tones. Image contrast is sacrificed somewhat when tones are compressed to bring an original’’s density down to a range that can be reproduced on a printing press.