ISO 105-B06:1998 pdf download – Textiles – Tests for colour fastness
6.2 Setting the exposure conditions for set No. 3
Fit the testing apparatus with clean xenon arc lamps and clean filters. The light-measuring system shall be calibrated according to the manufacturer’s instructions. Mount the exposure card with reference 6 (see 4.1 .1 ) in a specimen holder and then in the apparatus, with all other specimen holders containing white cards that are half-covered by an opaque cover with cutout. Interrupt exposure only to inspect the exposure card. Continue exposure until a contrast corresponding to rating 3 on the grey scale (see 4.2.6) is reached on reference 6 (see 4.1 .1 ). By experience radiant exposure of (250 to 300) kJ/m 2 at 420 nm corresponding to (1 1 to 1 3,2) MJ/m 2 between 300 nm and 400 nm is necessary. The contrast on reference 6 is best measured colorimetrically with a spectrophotometer. If faded to rating 3 of the grey scale, it corresponds to a value of 3,4 ± 0,4 DE* (CIELAB) for D65/1 0°. Before measuring, place the reference on unexposed card. When performing multiple exposures by method 3, inspect the specimens during the individual exposure periods, making sure that any deviations from the rated value are compensated during subsequent exposures, so that the sum of the deviations at the end of the series of exposures does not exceed ± 0,4 DE* (CIELAB). Compensation is achieved by adjusting the exposure time or dose. If agreed between the interested parties, the exposure may be continued until a contrast corresponding to rating 2 on the gray scale is reached on reference 6. This means twice the necessary radiant exposure.
6.3.1 Exposure method 1 (end point determined by colour change in the specimen)
This method is considered the most exact and should be used in cases of dispute over the numerical rating. The basic feature is the control of the exposure periods by inspection of the specimen and therefore, one set of blue wool references is required for each specimen under test. NOTE This exposure method is not used by the automotive industry and has therefore been omitted from this standard. For a detailed description see 7.2.1 of ISO 1 05-B02:1 994.
6.3.2 Exposure method 2 (end point determined by change in colour of reference)
Expose the specimens, half-covered by an opaque cover with cutout, and the references using the conditions given in 6.1 . Monitor the effect of the light by frequently checking the references. Continue exposure until a contrast corresponding to rating 3 or rating 2 on the grey scale for assessing change in colour is observed between the exposed and unexposed parts of reference 6. Rating 3 on grey scale corresponds to a value of 3,4 ± 0,4 DE* (CIELAB) for D65/1 0°.
6.3.3 Exposure method 3 (end point determined on the ageing test of 3.2)
Using set of exposure conditions No. 3 in 6.1 , subject the specimens to a prescribed number of exposures in accordance with the specification in 6.2. Each exposure requires a new reference 6. The minimum specimen size for multiple exposures depends on the subsequent assessment method. 6.3.4 Exposure method 4 (end point determined on radiant energy) Expose the specimens under set of conditions No. 3 or 5 (see 6.1 ) to a specified level of radiant exposure at a central wavelength of 340 nm, 420 nm or broad-band wavelength of 300 nm to 400 nm. The exact level of radiant exposure will depend on the material and the application, and shall be agreed on by the interested parties.