Creating that bleed-through effect should only seem like magic to the audience. However, lighting technicians need to wave their magic wands to create this seamless effect. The best kind of scrim to use for bleed throughs is the Sharkstooth Scrim. Sharkstooth is a flame retardant 100% cotton close-knit netting fabric. Consider Sharkstooth Scrim the invisibility cloak of the stage.
When Sharkstooth Scrim is lit from the front at an oblique angle and the area behind the scrim is dark, the scrim appears to be opaque. However, when the scene behind the scrim is illuminated it becomes “visible” and if the lights on the front of the scrim are removed, the scrim becomes virtually “invisible.”
Here’s a few tips to properly light a Sharkstooth Scrim.
First, any light behind the scrim will reflect on the scene that the scrim is trying to hide and allows the audience to see it. For the scrim to be most effective, the area behind it must be completely dark. Of course, the brighter the lighting on the scrim, the less likely that anyone will see a glimmer or gleam shining from behind the scrim. Still, every effort should be made to keep the area behind the scrim completely dark until the reveal occurs.
Second, proper angle of the LIGHTING IS CRITICAL. If the area is as dark as possible, but the scene is still visible through the lit scrim, then consider the angle of the lighting. Ideally, the lighting on the scrim is at such a steep angle that it cannot possibly illuminate the scene behind it. Also, when you touch a sharkstooth scrim, one side is fairly smooth and the other has more texture. This does not affect the use of the scrim, but more texture gives the light extra surface area to touch and is slightly more visible to the audience.
Create an area of space between the scrim and any nearby scenery so that any light that spills through the scrim will not hit anything and won’t show to the audience. The most common way to achieve this is to have strip lighting directly in front of the scrim’s top. The majority of the light from the strips washes the front of the scrim and any excess light that shines through into the empty space between the scrim and the scenery is not visible.
Third, while not necessary, having blackout drapes behind the scrim will help hide the scenery behind it. If you have extra batons and a spare blackout drape, you can ensure that the audience will not see the hidden scenery by hanging the drape about a foot behind the scrim at the upstage edge and flying it out moments before the bleed-through. You will still need to control the spill upstage or the blackout drop will be visible, most particularly as it flies just before the bleed-through begins.
While having the proper lighting angles is paramount, knowing how NOT to light the scrim is useful too. Lighting from the front will certainly light the scrim, but it will also light everything behind the scrim as well. This is because the sharkstooth scrim is essentially a series of holes tied together. When lit from the front, the holes will let the lighting continue upstage and illuminate everything behind the scrim. Lighting from a balcony is also not an ideal position, as it may provide the maximum visibility of the scrim and the images behind it, for those who are sitting in the orchestra.
Equally important in making the scrim work is effectively lighting the scene behind the scrim. If you want the scrim to disappear when the dissolve is complete, the lighting for the scene to be exposed must all come from behind the scrim. Any lighting in front of the scrim may show the upstage scene, but will also continue to illuminate the scrim and any scenery painted on it. While this may be the desired effect that you are looking to achieve, for the scrim to disappear, it cannot be lit. The scene lighting should come upstage of the scrim or from side positions that are upstage from the scrim.