Cadmium yellow and light orange pigments are based on solid solutions of cadmium zinc sulphide : the deeper oranges and reds are based on the cadmium sulphoselenide system. In either case, barium sulphate may be present as an extender in some pigments in order to achieve the desired pigmentary strength.
| Composition: (Varies with pigment) |
CI Pigment Yellow 35 (77205) CI Pigment Orange 20 (77202) CI Pigment Red 108 (77202) CI Pigment White 21 (77120) |
| Density: | approximately 3.5 - 5.5 g cm-3 |
| Oil absorption: | typically 17 - 22 cm3 per 100 g pigment |
| Mean particle size: | approximately 0.5 µm (by X-ray Sedigraph) |
| Sieve residue: | < 0.1 % (240's mesh, 63 µm aperture) |
| Acid-soluble cadmium: | < 0.01 % (Council of Europe test method) |
| Moisture: | < 0.5 % |
Testing and assessment
Whenever these are known, batches of pigment are tested against the physical standard using the customer's conditions of use i.e. resin and loadings. If these have not been advised, then testing in high-density polyethylene is used, with loadings of 0.5 % pigment for masstone and 0.5 % titanium dioxide + 0.05 % pigment for assessment of tinting strength.
Both visual and instrumental determination of colour differences are used. Conditions for instrumental use are 10º observer and D65 illuminant. Unless otherwise agreed, a maximum colour difference of delta E of 1.0 (CIELAB equation) is considered acceptable.
Please note that this information is given for general purposes and does not constitute a specification of any sort.