Holographic diffraction grating film is used to break up white light into all the colors of the spectrum. It is an ideal choice for spectroscopy experiments, since holographic gratings exhibit significantly sharper diffraction orders than their ruled counterparts by reducing the amount of stray light produced. This results in an increased ability to view absorption and emission lines, with higher spatial frequency gratings.
Diffraction grating is offered in 1000 or 500 lines/mm. More lines spread the spectrum wider, so if you want to produce 'big rainbows' choose the 1000 lines/mm. Less lines produce more, narrower spectra - unlike prisms, several spectra, or 'orders' can be produced.
Other sizes available on request, up to 6" wide x several inches or feet. Note that this material is highly electrostatic and picks up dust and fingerprints very easily!
A diffraction grating is an optical component with a regular pattern, which splits (diffracts) light into several beams travelling in different directions. The directions of these beams depend on the spacing of the grating and the wavelength of the light so that the grating acts as a dispersive element. Because of this, gratings are commonly used in monochromators and spectrometers. (wikipedia)