Projection film High Gain, cream

In order to plasticize PVC, the hard PVC powder is mixed together with a plasticizer in a heating mixer. The plasticizers reduce the hardness of the plastic but do not chemically bind with the plastic. Because of this they tend to be volatile which means that plasticized PVC does not generally remain soft forever. Soft PVC films are accordingly not suitable for outdoor use.

Even though most plasticizers are physiologically harmless, the use of plastics containing plasticizers in the foodstuffs sector or for children’s toys is not advised.

In addition to the conventional plasticizers, so-called flexibilizers are also used for making soft-PVC. These materials do make a chemical bond with the PVC and are therefore not volatile. “Flexibilized” PVC films consequently remain soft for a much longer time. PVC that has been plasticized in this way is referred to as “polymer plasticized PVC”. Unless otherwise stated, the soft-PVC semi-finished products that we have on offer are made from basic monomer plasticized PVC.

One side of this film has a ripple texture and it is that, in conjunction with the film’s mother-of-pearl pigmentation, that is responsible for the film’s unusually high light density factor (gain) during front projections at a 0° viewing angle. When used for front projections, the High Gain film manifests a directional response pattern, which means that it bundles the light towards the middle of the screen so that a particularly bright projection is achieved at the 0° viewing angle. This also makes the film ideal for use on large screens with low-powered projectors. If you are working with one projection surface with both front and rear projection techniques, the High Gain should be considered the best choice of screen. The intense texture on the one side leads to a singularity: the textured side must always be on the opposite side from the viewer. Considering this, you can see that changing from a front to a rear projection is as easy as flipping a switch.

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.

Please note: the textured side of this projection screen should always face away from the viewer.