Cinematography-Theory-And-Practice

Figure 16.8. A very large bluescreensetup: there are rows of KinoFlo units rigged from above andanother row near the floor. (Photocourtesy of Kino Flo.)There must be a load on the circuit to read the output. The shorterrise time can sometimes cause filament sing. In most cases, withproperly grounded audio systems, there should be no problem, but aportable radio can be used to test and find the source of any trouble.When using an SCR dimmer with a generator, the gennie must befrequency controlled, or the loss of sync will cause flicker; also, sincemost dimmers are voltage regulated, raising the voltage of the generatorwill not increase the output. An anomaly of these systems isthat the neutral load can, in some cases, be higher than the hot line.SCR dimmers are basically theatrical equipment, so their connectorswill often not be compatible with the rest of your equipment.As a rule the outputs will be theatrical three-pin connectors, either60 amp or 100 amp. It is important to order adapters to whateverplugging system your are using.The input side of most dimmer packs are Camlock connectors. Frequentlythe neutral is reversed (male instead of female); the easiestway to run into trouble with dimmer orders is to forget to orderfeeder cable with the neutral reversed or “turnarounds”: female tofemale connectors. Besides SCRs there are several types of electronicdimmers that work in various ways to reduce the ability of the electricityto make the tungsten filament produce light. These electronicdimmers are also used to control other types of sources such as HMIunits, fluorescents, or neon lights.Control panels vary in sophistication. Some are simply sets of sliderswitches, one for each circuit, and others include masters and submastersand may have separate banks for X and Y scenes, makingit possible to do a cue from one preset to another. The next levelis “soft patching,” which allows for electronic routing of each lineto a dimming circuit. The most advanced feature computer control,timed cues, and other sophisticated control features. Most controlpanels (dimmer boards) will run any set of dimmers. The standardfor remotely controlling dimmers is called DMX; make sure thatyour control board and your dimmers match in terms of controlstandards and connectors. The effect of dimming on color temperaturevaries with the source, as is shown in Table 16.4. It is possible touse dimming to establish a warm color look for the scene.cinematography316