Month: August 2013
Custom Gobo Ideas from GoboMan
Pictures of custom gobos.
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Can I use any lighting fixture as a gobo projector?
NO, gobos can only be used in lighting fixtures that allow you to focus the beam of light. Primarily, the fixtures used for gobo projection are Ellipsoidal Reflector Spotlights, so named because they have a reflector that is shaped like a portion of an ellipse, wrapping around the lamp nearly 240 degrees. This feature, along with a pair of plano-convex lens, allow one to focus on an image.
New technology ushered in new instruments that were brighter, cooler and more efficient. The ETC Source Four and the Altman Shakespeare, ADJ,Martin, Chauvet,and many of the new cooler LED fixtures are becoming industry standards. The gate area in some of these new ellipsoidals only reach temperatures of around 500 degrees, compared to previous units that reached 1600 degrees easily. The cooler units not only extended steel gobo life, but started a new world of custom and stock glass gobos, previously you would have needed a projector with a fan to keep from cracking the glass gobo. Many of the LED projectors allow you the option to make your own gobos on your printer.
How much detail can you get in a steel gobo?
Why there is no such thing as a standard size gobo?
People often say they would like to order or make a standard size gobo. The problem with this is statement is, that there is no standard size for gobos.
There are certainly some gobo sizes that are more popular than others, but there is no standard size in the Gobo world.
The reason is that each lighting instrument that projects gobos takes it’s own unique gobo size, and because sizes are different, some gobos can fit much more writing, or a larger design, than others can. There are over 75 different gobo sizes and each fixture takes it’s own unique gobo size. Gobo sizes are usually referred to with a corresponding letter, like A size, B size, M size, D size, or even Q size. If you do not know the name or the size of gobo you need, the two sizes that you will need are, the OD (outside diameter), and the IA (image area), the IA is where the design will be placed on the gobo. For example, A size gobos have a 100 mm OD, and a 75 mm IA, but the Q size gobo for the GoboMan projectors, has only a 22mm IA, and a 49 mm outside diameter, so obviously the A size will fit much more writing and a larger design than the Q size gobo. That said, you can still get up to 13 letters on a Q size gobo depending on the font used. You don’t want to try to get to much on a gobo because you can end up with tiny letters that don’t project a lot of light .
There are many websites online that provide lists of which lighting instruments take which gobo size and what the exact measurements are. There must also be a match between the gobo size and the correct sized gobo holder. This is also not a standard size. A good example of this is the ETC Source Four, which can take either a A size gobo holder or a B size gobo holder and also a glass pattern holder, so not all gobo holders are the same, or a standard size.
What is the difference between glass gobos and steel gobos?
We get many questions about the differences between Glass Gobos and Steel Gobos.
With a steel gobo, think of it as sort of like a stencil- The design is being cut through the metal, which would require tab support lines to keep the image intact- holding in the centers of letters, things like that. Steel gobos project white light or a single color by using a gel. Glass gobos employ a dichroic coating process on top of the glass, so they do not require support tabs, and can be muti-color. The cost of glass is almost 4 times as much as the cost of steel, so it’s important to take into consideration not only your personal aesthetic, but also your budget concerns. Please contact us at https://www.goboman.com if you have any further questions or need help designing your custom gobo.
What size gobo holder fits a ETC Source Four?
The truth is that the Regular ETC Source Four 575 watt and 750 watt units have a choice of three gobo holders available, and the ETC Source Four Jr. has two gobo holder options available.
The 575watt and the 750 watt units can either accept an A size gobo holder, or a B size gobo holder, or a glass gobo holder.
The ETC 575 watt Source Four Jr. takes an M size holder, or glass M size gobo holder.
How to know what ETC Source Four lens to choose?
How to sharpen your gobo image using a donut
A donut, is a thin metal or cardboard panel, similar in shape and appearance to a color frame, but with a small diameter hole intended to reduce off-axis rays of light being projected from a fixture.This increases sharpness of the light by reducing the effect of imperfect lenses. Donuts are designed to fit into the color frame holder directly outside the fixture, immediately in front of lens assembly. Because they are typically thin, doughnuts can often be placed in the same slot as a gel frame. Doughnuts are typically used in fixtures in order to sharpen the beam when a template is in place.
Used to increase the clarity of patterns and custom gobos by reducing halation therefore sharpening the projected image. The donut sharpens the definition of projected gobo images by blocking the unwanted light.