Build a screen for the projector itself

A beamer turns the television picture home theater. To be able to enjoy the presentation perfectly, a smooth coated projection surface is needed. Empty walls of the required dimensions are rare and bed sheets or towels swallow contrasts and cast wrinkles. A mobile or static canvas is easy to build yourself.

Select raw material canvas cloth suitable

Projectors are now available at moderate prices. Both TV picture and the image of game consoles can be projected on life-size on suitable surfaces. Theoretically, a free white wall surface or a white cloth is enough like a bed sheet. To get a razor-sharp image with good contrasts and no annoying side effects like drape, a canvas is the better solution.

Canvas cloth forms the basis of the projection screen. The linen cloth is coated with pigments that influence light absorption and reflection. Inexpensive plastic linen cloths have shorter lives than linen. The cloths are available with different pigmentations mostly by the meter. Further selection criteria for the suitable linen cloth for self-construction are:

  • Viewing distance and resolution points
  • Size ratio between height and width
  • Reflection width of the image to the sides (gain factor)

Position of the beamer and gain factor

When planning for a projection of images from a projector, its position is essential for the matching and optimal screen. First, the efficiency of the beamer determines the possible distance. The usual devices suitable for a home theater provide sufficient light and radiance up to five meters away and three meters screen diagonal.

If the light from the projector strikes the screen at an angle, the screencloth must have a higher gain factor. For home cinema screens, only gain factors between 0.75 and 1.5 should be selected. For the exact calculation of the ideal gain factor the Finzel formula is used:

  • Multiply the image width by ten
  • Set result in square (high two)
  • Divide the result by the ANSI lumen value of the beamer

Durable or flexible canvas

After the determination of the ideal linen cloth, the integration of the canvas into the living space is up for discussion. In principle, there are two ways of constructing:

  • Hang up the canvas hanging loose
  • Attach framed canvas to the wall or set up freely

Each loose and frameless suspension requires a draw weight at the bottom of the screen. It smoothes the cloth and prevents movement and vibration. Room air moves a canvas already by opening the door or getting up or arriving a spectator.

Weights can be firmly fixed to the canvas base or temporarily fixed. As weights serve for example:

  • Fixed wooden slat
  • Fixed metal profile strip
  • Clip trailer with weights
  • Tablecloth weights with clip function

Canvas cloth can be rolled up in higher quality versions. This allows loosely suspended and tensioned screens to roll up and store them when not in use. With spring mechanism, similar to a winding awning or a shutter mechanism, the installation in the ceiling is an attractive and space-saving design variant. A canvas box, let into the ceiling or put on, picks up the linen cloth on a wave. Running rails or guide grommets ensure a straight winding run of the canvas edges. The edges should be reinforced by glued or sewn seams.

Canvas as frame construction

In general, a canvas is always clamped and never screwed or glued. So if a frame canvas itself is built, the frame is used for hanging or stretching the canvas cloth.

A rectangle of wooden strips serves as a frame. The corners put together with miter cuts form a flat flat frame. As corner joints and couplings can serve. Large frames with side lengths of more than one meter can be stabilized by diagonal support strips.

On the back of the frame, hooks or eyelets are screwed around at intervals of about ten centimeters. They serve as holders for the retaining rubbers. In the linen cloth metal eyelets are punched at equal intervals. For smaller screens and a very large number of rubber mounts, it may be sufficient to use punched holes instead of metal eyelets.

Clamping the linen cloth

The cloth is trimmed so that it can be beaten three to five centimeters over the frame. The corners are folded over one another. Through each hole or each eyelet of the canvas Einmachgummis be performed twice, so that they form a loop. The loop is hooked in each case in the opposite hook.

When stringing the frame we clamped on each side from the middle to the corners. At the corners two tight crossover rubbers are placed. The distance to the respective frame edge should not exceed two centimeters. After stringing, the canvas is ready to be hung, for example, on wall hooks. A slow hanging procedure prevents the screen from "bloating" in the frame due to air resistance.

Tips & Tricks

Cover a frame with linen cloth with an assistant. Only in this way can you offset and correct any folds by individually increasing individual stress points.

Product Image: pp1 / Shutterstock

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