Glass vs Metal image projectors
A gobo is a circular piece of glass or metal which projects an image or pattern onto almost any surface when placed into a projector. These light projectors can be used at events such as weddings, birthdays, or will sometimes found in bars and nightclubs.
Other than the fact that they’re made from different materials, have you ever thought, what are the real differences between glass and metal gobo projectors? What are the benefits of using one over the other or does it even matter? In this article, we’re going to discuss the differences and give you a better understanding of which one you would be better off purchasing. When making the decision remember to keep the following in mind:
Metal gobos are cut from a single sheet of metal. So, unless the light uses a coloured filter, only the light can be seen when projected through a metal gobo stencil. This makes a good choice for wedding gobos to project the bride and groom’s names making it as bright as possible.
Glass gobos can be made with a variety of colours; each colour is on a new layer of glass (to see how the layers adhere together, you can see our “how to make a gobo” blog). Because glass gobos are made up of CYMK glass which we can find the closest fit for to project your comapny logo.
Metal gobo are more cost effective as the raw material is cheaper than glass. We use a brass sheet to manufacturer your gobo due to a high resistance to heat (see below)
Metal gobos (especially steel) wear out quicker than glass ones because they are less resistant to the heat of the projector. Older projectors can cause “hot spots” which could still crack a glass gobo, so be careful what projector you’re using and keep an eye on your gobo to ensure the best quality.
However, over time, glass gobos have become more resistant to heat due to them now being made of a high-temperature borosilicate glass which has a reflective coating meaning the light isn't absorbed like other types of glass.
Keep in mind, if the gobo is only going to be used once, the heat resistance of the glass or metal isn’t going to be an issue.
Tagging is when a small piece of metal is used to connect shapes in the gobo. For example, you can see through metal gobos, so for letters and shapes with a cut-out middle, this technique is used to piece it together.
Metal gobos, act as more of a stencil, so when creating letters such as ‘P’ or ‘O’ (with a cut-out middle section), they would need to use tags to keep it in place. Bear in mind though; this is so faint that it can rarely be seen on the projected image.
A glass gobo, on the other hand, is transparent as the surface is eched away to let light through; this means tagging isn’t needed as the gobo is left clear where the image is required.
A glass gobo is better suited for a piece of artwork with multiple colours and more intricate designs. Each new colour has its layer. Bespoke gobos, such as a company logo would usually be made out of glass.
To clean your glass gobo, you’ll need a lint-free dust cloth and depending on how heavy the stains are; you might also need some isopropyl alcohol.
To remove fingerprints, oils and dust, wipe over the glass pattern with the lint-free dust cloth. For anything tougher, this is when you should use isopropyl alcohol but make sure you don’t pour it over the gobo itself! Glass gobos are made up of a number of layers, and if the liquid gets in between two of the layers then it might change the appearance of the image. Instead, dab the lint-free dust cloth into the isopropyl alcohol and wipe over the glass in a circular motion, starting from the centre (be sure not to go to close to the outer edge though).
If you’d like any more information on glass or metal gobos or you’d like to design your own, you can contact us via email [email protected] or call us on 0191 265 9832.