Now we are in a position to characterise our objects:

a) Diffusing surfaces are those that possess surface colour. Their colour attributes come from diffuse reflection and their geometric attribute is glossiness from specular reflection. Their colour attributes are described in terms of lightness, hue and saturation.

b) Metallic Surfaces possess a colour attribute from specular reflection. They are described by their glossiness, hue and saturation. Their geometric attribute is a slight colour blurring due to surface diffusion.

c) Translucent objects have colour mainly from diffuse transmission. They possess colour attributes of translucency, hue and saturation and geometrically glossiness by specular reflection.

d) Transparent objects have colour from transmission. This is described in terms of clarity, hue and saturation. Geometrically there may be a slight blurring due to diffuse transmission.

The following paragraphs explain how we can maintain colour consistency across systems and how we may assess a given colour against another. This would be very important for example, if you were producing a multimedia product for a fashion house. In order to assess colour systematically and consistently, it is necessary to quantitatively evaluate the light from the surface or object. Quantitative evaluation of light from objects is particularly important to manufacturing industries involved in presentation products. i.e. washing powders, paints, and much of the research is directed towards their needs. Test samples are usually made of flat uniform materials and the light is controlled to ensure stable test conditions. The light may be reflected or transmitted in a different manner for a given material depending upon the following:

a) The incident angle of the light.
b) The observer's viewpoint.
c) The spectral content of the lightsource.
d) The refractive indices of the materials constituents.

Attachment:- Assignment.pdf