Grain is the physical property of a developed emulsion that creates the impression of fine speckles—light spots on a dark background, or vice versa. Every negative has grain, but it becomes truly noticeable in a positive that has been enlarged several times: the print shows a tonally inverted and enlarged copy of the negative’s grain. Grain is most noticeable in large areas of light, uniform midtones—such as a person’s face, the sky, or snow. A grainy print that has already been developed can only be corrected through retouching.
Causes of Graininess in Negatives
Coarse grain in high-speed film—the higher the emulsion's light sensitivity, the coarser its grain.
Aging of unexposed emulsion due to prolonged or improper storage, especially at elevated temperatures.
A blurry image can be caused by incorrect focus, a dirty lens, or softening filters.
Low contrast between the subject and the background in the scene being photographed.
The subject is small within the frame, which means the image has to be enlarged more when printed—and with it, the visible grain.
Overexposure or underexposure when taking a photo.
There is too much variation in exposure and contrast among the scenes within a single roll of film.
Improper or prolonged storage of film that has been exposed but not yet developed—especially in warm and humid conditions.
A developer that is improperly formulated, depleted, or contaminated with foreign substances.
The developer was not properly selected for the type of film.
Re-developing a negative.
Accelerated drying of developed film using a hair dryer at a high temperature and with very dry air.
Printing using the focused, direct light from the enlarger—a condenser without a diffuser or frosted glass.
Printed on glossy photo paper.
Too abrupt a focus adjustment and excessive stopping down of the enlarger lens during printing.
How to Reduce Grain When Shooting
Whenever possible, use low-speed, fine-grain film, and do not shoot with film that has expired. Keep your lens clean and focus carefully, unless blur is intentional. Try to shoot in high-contrast lighting and fill the frame as much as possible with your subject to avoid excessive enlargement when printing. Use the correct exposure and aim for consistent lighting throughout a single roll of film.
How to Reduce Grain During Development and Printing
Develop the exposed film as quickly as possible, using only freshly prepared developer with precisely weighed and clean chemicals. For low-speed, fine-grain film, use fine-grain equalizing developers; for high-speed, coarse-grain film, use extra-fine-grain formulations. Avoid overdeveloping: aim for a negative with a low contrast ratio. Do not artificially speed up the drying of the negatives.
When printing, use an enlarger with a diffusing (matte) glass plate, and for high magnifications, use matte paper with a rough or textured surface. You can slightly soften the sharpness of the image by shifting the lens slightly away from the point of maximum sharpness or by using a diffuser—a mesh made of tulle or gauze—in front of the enlarger’s lens.
If you follow these recommendations, you can produce a satisfactory print even when the negative is enlarged twenty times. It is impossible to completely eliminate grain, but it is entirely possible to minimize it.
Based on material from V.P. Mikulin's book.