Many LED light sources have a shorter throw distance and beam spread, meaning you need to put the fixtures closer to the stage and you need more fixtures to cover the same area you might cover with a single tungsten fixture. Check the manufacturer specifications to determine the beam spread and plan your design accordingly. Test fixtures before buying by renting the unit and testing it out on your stage to see how it looks in a real-world application.
Color filters, also called gels, will look different when used with LED lights, compared with standard lighting instruments. White LEDs produce a different color temperature light than other lamps, adding less warmth to your color. When choosing gels, turn off the lights and shine an LED flashlight through the gel onto your set or skin to see how the color will look in your LED fixtures.
If you use colored LEDs rather than gels to produce color, be aware that LED color mixing works differently due to light wavelength characteristics. This means certain colors will be stronger than others and may react oddly with colors onstage in the costumes and paint. Choose LED fixtures that include amber along with the standard red, blue and green LEDs to get the best color results.
You can control dozens of LED fixtures through a single circuit because of the low wattage draw, which is appealing for spaces with limited control circuits. However, controlling all of your fixtures on the same circuit limits your potential for isolating areas of the stage with light. Plan your circuiting carefully to maximize both your available power and your versatility.
To make the best of your light plot, use LED color-changing fixtures for your color washes and special effects, but use standard tungsten or halogen fixtures for face lighting and to control general area lights. This gives you the benefit of control and true color on your performers and the versatility of LEDs for your backgrounds and effects.