Projection film Scene, white/black

Attributes: A clear statement concerning the colour of light is always difficult because light exists in conjunction with heat. Not every plastic film is able to withstand the heat produced by certain bulbs. Rosco E-Colour filter films were developed for use in theatre and film work and are therefore capable of colouring a beam of light produced by a powerful spotlight. Exposing the E-Colour filter films to long term UV illumination can produce a mild bleaching of the film.

In order to get an impression of the colour that will be produced using a particular film, the chosen light source should be shined through the relevant colour from the colour samples onto a surface. Just holding the film in front of your eyes and looking into the light will usually give a false impression.

Applications: When constructing a lamp a few points should be observed: the heat that a colour filter must withstand is not just dependent on its separation distance from an incandescent or halogen bulb. Much more important is the ventilation that the lamp allows. In the same way that the classic writing table lamp has a reflector with holes on its top side, a self-made lamp should be so constructed that the rising heat from the light source has an escape route. In this way the lamp produces, as if on its own, a cooling stream of air. A further issue concerning heat: the heat produced by a spotlight with a reflector is usually greater than that from one with a system of lenses because the reflector, in contrast to lenses, also tends to gather heat.

One easy way to make a lamp is to simply wrap colour filter film around a fluorescent tube. The temperature of a fluorescent tube is much lower than that of other illuminants so it is OK to just directly wrap the film around the tube. In this case, as also in the case of constructing any lamp with an incandescent or halogen bulb, the best agent for holding the film in place is SCOTCH MAGIC TAPE because it can withstand heat up to 150° C.

Treatment: Colour filter films are very thin which means they can be easily cut using a BLADE or SHEARS. This thinness and lack of strength is a disadvantage when the planned construction requires an inherent stability. This problem can be solved by using perforated sheets, wire mesh or expanded metal as a carrier material allowing for as much open area as possible (a_o). Because of high resistance to heat, POLYCARBONATE or POLYPROPYLENE panels can also be used as long as enough ventilation is provided for in the lamp. Colour filter films can be attached to one another or to other materials with heat-resistant ADHESIVE TAPES, rivets or clamps. Please take into account the different expansion rates for any materials used in a construction that will be exposed to extreme fluctuations of heat. You should resist, for example, gluing a large area of metal with filter film because the resulting stress will quickly fatigue the adherence.

The projection screen Scene is two-ply: It is made up of a bright white front side and a deep black rear side. This makes it only suitable for front projections and also makes it completely opaque; this means that light that originates from behind the screen has no effect on a projection as is often occurs with light permeable films in such a situation. The black layer is primarily there to serve a blackout function but can in fact be used as a projection screen itself provided that a high-powered projector is being used. When the conventional side, i.e. the white side, is being used, Scene is a superlative projection screen that produces a homogenous brightness distribution combined with a high degree of reflection.

The “gain factor” (light density factor) specifies how much of the incident light (e.g. from a video projector) will be reflected back from a reflecting surface. The gain factor is given for different viewing angles. The light density (and thereby the amount of light that reaches the viewer’s eye) is greatest when the projected light arrives in a vertical direction onto the screen and the viewer is looking along the same axis. The projection axis and the optical axis are in this case the same, the viewing angle is, then, 0°. This is where the maximum „gain“ is measured. A gain factor of 1.0 means that the same amount of light that lands on the screen will be reflected back. A factor of less than 1.0 means that less light will be reflected while, of course, a factor greater than 1.0 means that the light from the given angle is being bundled together to an unusual extent and is therefore particularly bright. The more diaphanous rear projection films, which are more transparent and therefore allow almost all the incident light to “pass through” them (transmission) and thereby reflect away only a tiny amount, have an especially high gain factor at a 0° viewing angle.

Now about the diagrams: The straighter the distribution curve appears, the more even and uniform the projection will appear when being viewed from different angles.

A high gain factor film is the best choice when projecting a somewhat “concentrated picture” in a brighter environment (daylight) or when using a low-luminance projector. On the other hand, indoor (darkened if need be) projections or ones in which you are using a high-luminance projector require a change of priority. In those cases you need to look for the greatest possible evenness of light distribution – i.e., you should concentrate on a consistent and uniform gain factor distribution for your film (see diagram).

Colour rendering: The quality of a projection film’s colour rendering has less to do with the degree of reflection or transmission but rather more with the consistency and uniformity evident in the colours of the colour spectrum being rendered; no single colour should really stand out from the others. All the projection films we carry have a marked consistency and therefore a realistic rendering of colours.

Processing: These films are in general really easy to work with. For example, the soft-PVC can be folded and sewn to make a tunnel shape into which a tube can be inserted in order to allow the film to hang from it or, alternatively, to weigh it down. Another possibility: Fold in all the sides of the film, glue them in place (SOFT-PVC GLUE) and/or sew them, add eyelets and stretch the film out (span a space). You can also simply staple the film to a wooden frame.

If you want to increase the brilliance of a projected picture, you can put a piece of black MOLLETON behind the film but this, of course, only works for front projections. This projection film has a visible texture on one side; it should, regardless of which side is being projected on, face the viewer.