Improvements in or relating to film and/or coatings

A material for controlling plant growth, by selective absorption of light in the 700 to 800 nm waveband whilst maintaining high transmission of photosynthetically active radiation (PAR) (wavelength 400 nm to 700 nm approximately) comprises a carrier incorporating a phthalocyanine derivative represented by the general formula I below wherein the substituents R 1 , R 2 , R 3 , R 4 may be respectively the same or different groups selected from hydrogen, alkyl, aryl, alkoxy, halogeno, or other functional groups which do not adversely affect the stability or selective absorption performance of the material, and M is a metal atom selected from Mg, Fe, Co, Ni, Cu, Zn, and Mn. Furthermore, heat build up in greenhouses is controllable by use of a film which inhibits transmission of light in the near to infra red region but permits a high transmission of PAR and comprises a laminate wherein at least one layer is a polymeric film which contains a dispersion of gas bubbles having a size predominantly in the range of 50 ~ m to 500 ~ m as determined by microscopic examination in the plane of the film.