Film Negatives

Information on Film Negatives

Photographic film is a strip or sheet of transparent plastic film base coated on one side with a gelatin emulsion containing microscopically small light-sensitive silver halide crystals, size and other characteristics of the crystals determine the sensitivity, contrast and resolution of the film.

The emulsion will gradually darken if left exposed to light, but the process is too slow and incomplete to be of any practical use. Instead, a very short exposure to the image formed by a camera lens is used to produce only a very slight chemical change, proportional to the amount of light absorbed by each crystal. This creates an invisible latent image in the emulsion, which can be chemically developed into a visible photograph. In addition to visible light, all films are sensitive to ultraviolet, X-rays and high-energy particles. Unmodified silver halide crystals are sensitive only to the blue part of the visible spectrum, producing unnatural-looking renditions of some colored subjects. This problem was overcome with the discovery that certain dyes, called sensitizing dyes, when adsorbed onto the silver halide crystals made them respond to other colors as well. First orthochromatic (sensitive to blue and green) and finally panchromatic (sensitive to all visible colors) films were developed. Panchromatic film renders all colors in shades of gray approximately matching their subjective brightness. By similar techniques special-purpose films can made sensitive into the infrared (IR) region of the spectrum.

In black-and-white photographic film there is usually one layer of silver salts. When the exposed grains are developed, the silver salts are converted to metallic silver, which blocks light and appears as the black part of the film negative.  During development, the exposed silver salts are converted to metallic silver, just as with black-and-white film. Because the by-products are created in direct proportion to the amount of exposure and development, the dye clouds formed are also in proportion to the exposure and development. Following development, the silver is converted back to silver salts in the bleach step. It is removed from the film in the fix step. Fixing leaves behind only the formed color dyes, which combine to make up the colored visible image.

Cleaning Film Negatives

Our achievers professionally clean film negatives, first using a hand held bulb duster or air blower to remove any small particles of dust, then using a small amount of distilled water onto soft cloth. Performed in circular motion, the damp cloth removes any unwanted residue. Once the air begins to dry the slight water layer, a second dry cloth is used to remove any remaining damp patches and creates a polished look which is best for when scanning the image. Please note: this is only done to the non-exposed side of the film negative as any cleaning process to the exposed side could result in damaging the image.

Scanning Film Negatives

Our digital team scan film negatives using the latest technology with very high resolution settings and scaling, from the minimum of 600dpi up to 1200dpi for large format reproduction. Using custom scan tray with sizes that hold all formats of film negatives to avoid any unnecessary handling, with a scan calibration distance is set to approx 1.2mm from the scan plane. We advise scanning emulsion side up so that your image appears in the correct orientation and black and white negatives are scanned using colour settings in RGB to hold more digital information. Our software has many different calibrations for all manufactures from Agfa, Konica, Ilford and Kodak which enables us to perform scans that closely represent the original picture.

Storing Film Negatives

Film negatives are relatively fragile and require careful handling to avoid bending and the emulsion on the film can be vulnerable to scratching. When archiving film negatives they should be carefully placed into acid free covers as pictured right. We recommend that they are then stored in hard folders to protect the film negatives from bending. They should also be kept at room temperature and avoid direct sunlight or extreme heat.