what is a contact sheet
contact sheet, proof sheet, contact print: a few names for nearly the same thing. a contact print is anything printed with the negative pressed to the paper, at its own size; a whole roll printed that way on one sheet is a contact sheet. it is made to look over every shot before anything is enlarged and choose what to print; it also stays with the negatives as their index. this page shows how one is made, and how to read it.
making
negatives in contact with the paper, then light.
the developed film is cut into short strips, laid on the paper and held flat against it, then given one exposure from the enlarger's light. right after that the paper is still white. in the developer the image comes up, with the negatives' tones reversed. nothing is enlarged, so each frame prints at the negative's own size — a whole roll fits on one sheet.
edges
the edges outside the frames carry numbers and lettering too.
the film's edges are printed at manufacture with numbers and letters. the numbers mark the frame positions: to have one frame printed, you give the lab the number beside it. on 35mm they usually run one to a frame, or one to a half frame. a half-frame camera takes two pictures to a frame on the same film, one number to each. the lettering names the film stock, repeated along the edge on every roll of it.
120 is the medium-format film, shot at a frame far larger than 35mm's. it has no sprocket holes. its edge carries numbers and lettering all the same. the numbers run at a fixed interval; the frame size is the camera's, so on some cameras numbers and frames drift apart. in utsushi : 1, that lettering is the U : 1 label, yours to rewrite in capitals; the numbers are set for you.
density
the whole sheet gets the same light for the same time.
every frame on a contact sheet is printed on the same paper under the same conditions; with no frame corrected on its own, a difference in brightness between frames is a difference in the negatives' density. a thin negative passes more light and prints dark; a dense one holds it back and prints light. all else equal, underexposed frames sit dark and overexposed ones pale. a negative's density comes from the subject and the camera exposure, and from how the film was developed, fog included. the row is a way to look back at how the roll was exposed.
marks
choosing happens on the paper, in grease pencil.
the finished sheet is marked straight on its surface with a grease pencil, and that is how the pictures get chosen: a circle on a frame to keep, a cross on one to drop, corner brackets around a crop are habits you will see. there is no fixed code; photographers and editors each have their own way. the marks let you read which frames caught the eye and how they were meant to be finished. in utsushi : 1 too, the marks are yours to draw.
reading
the whole sheet first, then one frame at a time.
reading a contact sheet starts with the whole roll in view. where similar frames run together, it is usually one scene shot several times; the differences between them point to the best one. the shooting order is not the order on the paper: you trace it through the edge numbers and how the pictures connect. last, a loupe on the frames that matter shows the detail. in utsushi : 1 too, you can zoom in on a frame to check the detail.