ISO 6:1993 pdf download – Photography – Black-and-white pictorial still Camera negative film/process Systems – Determination of ISO Speed.
3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 exposure, H: The time integral of illuminance on the film, measured in lux seconds. Amounts of exposure are often expressed in logarith- mit terms (log,& 3.2 Speed: A quantitative measure of the response of the photographic material to radiant energy for the specified conditions of exposure, processing and im- age measurement. 4 Sampling and storage In determining the ISO Speed of a product, it is im- portant that the evaluated samples yield the average results obtained by users. This will require evaluating several different batches periodically under the con- ditions specified in this International Standard. Prior to evaluation, the samples shall be stored according to the manufacturers’ recommendations for a length of time to simulate the average age at which the product is normally used. Several independent evaluations shall be made to ensure the proper calibration of equipment and processes. The basic objective in se- lecting and storing samples as described above is to ensure the film characteristics are representative of those obtained by a photographer at the time of use. 5 Test method 5.1 Principle Samples are exposed and processed as specified be- low. Density measurements are obtained from the resultant images to produce a sensitometric curve from which values are taken and used to determine ISO Speed.
5.3.3 Radiant energy quality The appropriate iluminant for the particular film type being exposed shall conform to the specifications given in ISO 7589. ISO speed may be determined using ISO sensitometric daylight, studio tungsten or photoflood illuminants. Since the speed of film/process combinations will depend on the type of illuminant used for determining ISO speed, the iluminant should be specified in use instructions. 5.3.4 Filters ISO speed shall be specified for use without a filter in front of the camera lens. If film is used with a colour filter in front of the camera lens, an“ equivalent” speed number can be used to determine the ex- posure of the film with the filter. ISO speed does not apply to the filtered conditions. 5.3.5 Modulation The total range of spectral diffuse transmission den- sity of each area of the light modulator throughout the wavelength interval from 400 nm to 700 nm shall not exceed 5 % of the average density obtained over the same interval or a value of 0,03, whichever is greater. In the interval from 360 nm to 400 nm, 10 % of this same average density, or a value of 0,06, whichever is greater, shall not be exceeded. If stepped increments are used, the base 10 logarithm of the exposure increment shall not be greater than 0,20. The width and length of a single step shall be adequate to obtain a uniform density within the read- ing aperture specified for densitometry.