Horticulturally, shadecloth has two main specifications; light transmission and UVR block (or block out) that determines the successful growth of plants, foliage, flowers and crops. Determining the balance is usually characterised by what is being grown, and where.
UVR Block is the percentage of ultraviolet radiation of wavelengths between 290nm and 400nm (see diagram), that is not transmitted through the shadecloth.
Light Transmission or PAR Transmission is the amount of light transmitted passing through the shadecloth. Technically, Photosynthetically Active Radiation (PAR) is effectively the proportion of visible light (see diagram) passing through the shadecloth in the range of 400nm to 770nm. It is a measure of how much effective light would reach plants shaded by the cloth.
Cover Factor refers to the measurement of percentage area of the shadecloth covered by the yarns and fibres. This percentage is usually close to the UVR Block Figure.
Shade Factor (Shade Co-efficient) is the percentage of ultraviolet and visible light, i.e., radiation of wavelengths between 290nm and 770nm (see diagram) not transmitted through the shadecloth.