When – And How – To Use Plastic Gobos In Your LED Lights

by Stan Schwartz

Seems like DJs, event lighting designers and theatrical lighting designers everywhere are using LED-based fixtures.  And many are anxious to use plastic gobos in those fixtures. Not so hard to understand.  LED lights generally produce much less heat than traditional tungsten units.  More important, the plastic gobos cost a lot less than steel or glass gobos.

So, if you’re lighting a wedding and the bride and groom want to project a couple of gobos… and you have access to LED-based spotlights … there’s around 80 bucks of savings right off the bat.

The other good reason to use Cool Ink gobos is that they cost the same for full color images as for black-and-white images.  Most of the designers we know would rather create a colorful projection, especially if the price is right.

But as attractive as these advantages are, there are a few caveats about using plastic gobos.  Here are some of them:

1. Plastic gobos won’t last as long as steel or glass gobos.

Of course, LED-based fixtures are cooler than traditional spotlights – but they’re not heat-free.  Our tests show, for example, that the ETC Source Four LED Daylight instrument generates 130 degrees Celsius at the gate, when a gobo is inserted.  That’s less than the heat at the gate of a tungsten Source Four – but it sure ain’t heat-free.  Generally, Cool Ink gobos will last 15 to 50 hours, depending on the image, the amount of ink coverage and the instrument in use.  That’s certainly enough for most events, but not for long-running shows or permanent installations.

2.Cool Ink HD gobos are often the better choice.

The HD version of the Rosco plastic gobos are usually chosen because the image requires higher resolution or you need it to last longer.  Rosco uses a different film for the HD product, which offers a true opaque for the black background.  Cool Ink HD Gobos are also sandwiched between two pieces of glass and are mounted in an aluminum bezel, which offers additional protection from the heat, as well as the ability to easily clean off fingerprints and dust. They readily fit into Rosco's glass gobo holders. Some LED luminaires we've tested only accept the HD version. Plus, they're not that much more expensive!

3. Not all LED fixtures can accept plastic gobos.

Rosco maintains a data base of LED fixtures that have successfully used the Cool Ink or Cool Ink HD gobos.  But it’s best to check with the fixture manufacturer to determine if the model you’re using can handle a plastic gobo in the gate.

4. Plastic gobos aren’t new!

Rosco has long offered plastic gobos which can be used in most traditional tungsten spotlights.  They need only an i-Pro Projector attached to the spotlight.  Click here for details about this projector. The techniques and technology used to produce i-Pro slides are the basis for the Cool Ink gobo development.

Your theatrical supply dealer can get a Rosco multi-color plastic gobo made from your artwork ASAP. Cool Ink ships next day, Cool Ink HD ships within 2 business days.  But if you’ve never bought an i-Pro slide or a Cool Ink gobo before, it’s probably a good idea to allow enough time to talk it over with Rosco’s gobo staff.  They are knowledgeable about which images work best and which LED instruments are most suitable.