Zone System

You use the Zone System to expose a negative by first looking at the scene to be photographed & deciding what areas of it you want to be black, very dark grey, middle grey, light middle grey, very light middle grey, extreme light grey & white is the final point.
Zone 0 is pure black no detail
Zone 1 is near black & may show some sign of image detail.
Zone 2 you begin to see some if little but some detail in the shadows.
Zone 3 this zone shows detail in the shadows.
Zone 4 Full texture & image structure is visible.
Zone 5 Middle grey 18% reflectance.
Zone 6 strong image structure & texture exists
Zone 7 is the zone in which you should place lightest grey areas & highlights for which you want to preserve the important image structure detail & highlights with texture.
Zone 8 Is to highlighted image structure & texture as Zone 2 is to shadow image structure.
Zone 9 Almost pure white but with a hint of image structure & texture opposite of Zone 1.

 Zone 10 is pure white & contains as much usable detail as  Zone 0