6. Colour Filters & Accessories
All PAR cans except for the PAR36 pinspot have a set of runners at the front where you can slot a colour frame. The colour frame is a folded sheet of metal with a hole in each side, into which a colour filter can be fitted. The PAR36 pinspot uses the lamp retaining clip to secure the colour filter instead.
Colour filters are available in a few different formats, but they all operate in the same way: they absorb or reflect all of the colours in white light, except for the one that they transmit. The most common by far is the thin plastic film often referred to as gel. This name comes from the coloured gelatine that was once applied to glass to colour lights used in theatres. Modern gel is a composition of laminate sheets, and the process of its production is a tightly controlled science. The biggest manufacture of gel is Lee Filters based in the UK. Lee Filters catalogue contains hundreds of different colours, available in either 0.55 x 1.22 metre sheets or 7.62 x 1.22 metre rolls. Also available are colour packs which contain a few different colours pre-cut to PAR can sizes.
Available almost exclusively for the PAR36 pinspot is the coloured cap. This cap is moulded to the same curve as that of the front of the PAR36 lamp, so that it fits neatly under the lamp retaining clip.
The alternative to gel is dichroic glass. Through a process of metal coating and laser etching, the glass can be coloured extremely precisely to replicate the colours available in gel. Dichroic glass has the advantage of having an extremely long life; this is because the glass reflects the light not transmitted, as apposed to absorbing it, and therefore does not heat up and fade as much as gel. However, dichroic glass is relatively expensive and fragile by comparison.
Another accessory that fits into the colour frame runners is the barndoor set, which is a rotatable set of four hinged flaps that cut into the beam and allow the user to tidy up light spill.