Atlantic Illumination Entertainment Lighting

AIEL Instructional

Stage Lighting Situations

Suggestions to Overcome
Problems Encountered
while Lighting the Stage



Controlling Spill Light


Won't Fit

Projected Patterns:

Projected Patterns:


  Controlling Spill Light

    One of the marks of a good lighting person is his or her ability to effectively prevent unwanted light, called `spill', from diluting other lighting on stage, unnecessarily shining into a performer's eyes, or annoying or distracting an audience. Beyond using shutters, barndoors, snoots and other accessories to control this, here are some specific suggestions:

  1. General Light Leakage from Fixtures. This problem is usually seen where stray light hits audience members in the eyes from stages where lighting fixtures are visible. Use black aluminum foil available from lighting supply stores. It can be placed directly onto hot fixtures to block light as necessary. Mold the foil into grooves and openings, and around the fittings so that it stays in place. NEVER use tape on stage lights; you will end up with a gluey mess.

  2. Light Leakage from Accessory Holders. On the front of most stage lighting fixtures is a set of clips or runners (guides) that are meant to hold the accessories mentioned previously. Fixtures with enclosed runners will prevent most spill, but those with clips do not.

       The worst offenders are clips that offer two positions. These are meant to hold more than one accessory, each in its own slot. Always place single accessories in the rear slot closest to the fixture to close the gap between it and where light is emitted. With some fixtures this is not possible because the slots are different widths. Thus, thicker accessories might only fit in the front ones. To fill the gap, place a black-painted gel frame into the rear position. If the light is to have no gel, put in an empty frame.


  Diluting Shadows

    On small stages or anywhere actors and objects lie close to flats or other objects, harsh shadows may appear. If this effect is undesired, here are some suggestions to tone down or eliminate them:

  1. Proscenium Curtain Shadows. These occur when the proscenium is too low for the height of the back curtain, and/or where the front lighting comes from too far above the top of the proscenium opening. It shows as a distinct line across the back curtain or flats as caused by the front washes.

       Outside of changing the proscenium opening or lighting positions, the way to eliminate this is to have a second set of lights for each colour of the front wash placed in positions where they can be focused onto the background from the shadow line upward. For each look, these secondary lights would be added at an intensity and colour that exactly matches that of the front wash at the background's location. Thus the shadows are filled in evenly.

  2. Actor Shadows. Because these move, they are harder to deal with. It could mean positioning the actors to stand farther away from anywhere a shadow might be projected, but this is usually impractical. Even if it is done, shadows will appear on the stage floor, although these are less distracting to an audience, and non existent for patrons seated below the stage floor level.

       Once again the answer is to add extra lights to illuminate all shadowed surfaces in the same colour as that which lights the actors. One must be careful though, to not have so high an intensity to the point where actors look dark by contrast. An issue here too, is when actors move close to an object or surface that is covered by these extra lights that he or she will suddenly come up brighter in intensity. On small stages with low ceilings this is almost always a problem.

       Another solution is to use multiple wash fixtures from different angles. Yes, each will cause its own shadow, but because light is also coming from other angles, the shadows are much lighter in appearance. If the Set Dresser can add items to the background, these shadows will be broken up, making them less objectionable.

  3. Partially Enclosed Areas. This usually takes the form of an overhang that blocks much of the lighting from a location and/or actors. It is not always easy to simply hang more fixtures within these areas, usually because of space constrictions. Placing them outside often means low hang points and the likelihood that actors will cross in front of their beams.

       If there is vertical room, try using a drop rod to lower one or more fixtures so that they can just see under the overhang. Move them in close to lessen the likelihood that actors won't cross the beam, and use diffusion to soften and widen the beams.

       A method to try is to reflect light into the area from the set or nearby objects, but this rarely works because it imposes restrictions on the Set Designer, and because other objects and actors might block the reflected light at times.

       Given that these areas are usually small, it may be possible to attach some household sockets with light bulbs or screw-base floodlights to give enough illumination. Arrange for the Set Designer to provide recesses or a valance to hide these lights. Try to keep them well away from actors so that they won't "white out" every time they pass close by.

       See if the Set Designer might use a light paint colour so that you may be able to use reflected light from interior fixtures. In particular, a light colour on the ceiling of the overhang could be used to bounce light and give a pleasing softness; the audience would not have to even see this colour if it could be masked by borders.


  Fixture Won't Fit

    In small spaces you may encounter a situation whereby the desired fixture won't fit at the desired hang point. Perhaps it hangs down too much, blocks another light or interferes with the set decoration. Try these possible solutions:

  1. Hang a Smaller Fixture. Look to see if a smaller fixture will provide the look required. It may need a brighter lamp to overcome the lower output of a smaller fixture, especially if one must use a wider angle light to achieve the same coverage.

  2. Hang Multiple Smaller Fixtures. To make up for low light or inedequate coverage, use multiple fixtures. You may even find that hanging multiple fixtures from a variety of angles might result in a pleasing alternative.

  3. Use a Drop Rod. To squeeze in a fixture around other lights or objects, or to get it out of the way of another light's beam, attach a drop rod to lower the fixture below the interferance of other items or to eliminate its own interferance. Choose a rod length that keeps the fixture close to the desired angle and height, and that does not lower the fixture to a point where its visibility becomes an issue.

  Projected Patterns: Sharpening

    When projecting images of metal or glass patterns (gobos) with an ellipsoidal spotlight, you may notice to one degree or another that the image is not clear, or that it has a halo around the parts that allow light through. Called "Spherical Abberation", it is caused by imprecise optics that don't focus each part of the image to the same spot. Stage lights don't need to be ultra precise when just projecting light, so few manufacturers provide more expensive lenses to correct this issue. Despite the fact that modern fixtures have improved immensely because pattern projection is so popular, you may want to have an image be more sharp than even their capabilities can provided. Here are some suggestions:

  1. Use Thin Patterns. Thick ones are more likely to scatter light from their edges.

  2. Test Fixtures. Take each fixture in your inventory and project the same pattern onto a flat, light-coloured surface. Tag the ones that give the sharpest image. Use these fixtures when precision of image really counts.

  3. Dim the Light. If you can live with a less-bright image, dim the fixture to lessen the halo effect.

  4. Use an Aperture. If you can live with a less-bright image, place an aperture into the fixture's accessory holder where a gel frame goes. This will block the light coming from the outside area of the lens system where the rays are least likely to be brought to an accurate focus.

       Make apertures by cutting white cardstock or sheet metal to fit the accessory holder. Then use a jar top or other round item to mark and cut out an opening in the middle. (It need not be perfectly round.) Make up several more, each with a different-sized opening. The smaller the opening, the sharper the image -- but also the dimmer it will be. Duplicate the most common sizes you will use.

       Be aware that if you plan to cut openings smaller than 50% of the lens diameter, the aperture should be metal. Cardstock can be used for the others because even with a 1000-watt lamp in your fixture, the majority of the heat projects through the centre of the lens.

       Typical minimum sizes for cardstock used in a fixture with a 750- or 1000-watt lamp are:
    • 150mm lens: 75mm Opening
    • 200mm lens: 100mm Opening
       Typical minimum sizes for cardstock used in a fixture with a 500-watt or 575-watt lamp can be a smaller percentage of lens diameter. Remember that such openings will project reduced image brightness.
    • 90mm lens: 35mm Opening
    • 115mm lens: 45mm Opening
    • 150mm lens: 60mm Opening
    • 200mm lens: 80mm Opening

  5. Test Cardstock Apertures! The above are basic guidelines. Fixture misalignment may cause burnt apertures even with larger openings. To check, run the cardstock with various openings in a fixture with no pattern, and done in an open area for fire safety. Observe to be sure there is no smoke. (Shut down immediately if there is.) After 10 minutes, shut off the fixture and inspect the cardstock to be sure there is no charring around the opening's edges. Should there be, make apertures of this size from metal. (Some discolouration around the cardstock's opening is normal after long-term usage.)

  6. Flat-Field Align Fixtures. As mentioned, misalignment can burn apertures. In addition, fixtures used for pattern projection should be typically aligned to be Flat Field. That is, the light across the beam should be regular and as even in intensity as possible. Special reasons aside, images should not show hot spots or dark areas.

       Regarding special reasons, it may be desirable to have some patterns, some of the time, be brighter in one area or another. A cityscape with clouds may benefit if the sky part is brighter than around the building lines. Perform the alignment change with the pattern in place and oriented as desired. Project onto a flat, white screen, wall, or material, and if possible, from a distance that is comparable to that expected on stage. Be sure to tag this fixture as off-centre aligned so that it can be re-aligned for future shows before it is rehung.

  Projected Patterns: Softening

    For times when subtle images, or the look of an amorphorus shape or shapes is desired, focused projections will be too sharp, too well defined. Try these suggestions:

  1. Defocus the Light. This is the most obvious approach. Vary the focus adjustment of the fixture to set the projection clarity to suit your purpose -- make it slightly soft-edged, or be extreme and show the image as completely unrecognisable.

       Regarding the former, sometimes a slightly indistinct projection is wanted. For the case of foliage or clouds that are well upstage of the acting area, a soft, but recognisable image gives the impression of distance. This can give the feeling of slightly enlarging the space on the stage. Because of viewing film and video, people today are used to the technique of out-of-focus backgrounds, so it is quite acceptable to the live eye. In addition, such a defocused image will give the impression of hazy distance, which is also acceptable to the live eye.

       Oppositly, having a projection that will be completely unrecognisable from its actual design is the extreme of the defocusing technique. Because this will result in the appearance of a shape that has no resemblance to any image, different interpretations by various audience members might be realised. For those that take the time to consider it, each will make of it what he or she believes it represents. This sometimes evokes responses that can take a scene to another level in their minds.

       Be aware that defocusing a projected pattern will usually increase the halo effect. This can be reduced by dimming the light and/or using an aperture, both as previously discussed. On the other hand, some images benefit from the halo; ornaments, snowflakes, and water are examples.

  2. Use Diffusion. A method to slightily soften an image without defocusing is to use a diffusion medium. This has the advantage of being able to maintain a sharp focus of the fixture so as to keep halo to a minimum. A very light frost will soften an image while keeping the subject of the pattern intact. This technique works nicely for a pattern seen through a window on the set.

       For a surreal effect, use a light silk gel to stretch the projection while diffusing it. This will give a streaked look to most images.

  3. Keystone the Image. Hanging the fixture off to the side of the projection surface will elongate the image. The stretched result will not sharply focus over the whole surface. Instead, a graduated sharpness will be seen that can work nicely for things which can be allowed to start or end out of focus. An example might be a long fence or wall that recedes into the distance.

Employing the methods discussed on this page
will impart a more artistic look to your lighting.

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