Creating Custom Gobos that Map Perfectly to Building Facades
When it comes to exterior lighting design, creating custom gobos that are accurately mapped to building facades can be a bit challenging and sometimes tricky. This article was written to be of help in this area.
Outdoor rated image projectors such as the Martin by HARMAN Exterior Projection 500 and Exterior Projection 1000, enable lighting specifiers and architects to enhance a building façade or structure by integrating textures, patterns, and graphics for limitless creative exterior lighting designs. This is all based on a low-maintenance and low-running cost solution using powerful LED-based fixtures designed for permanent outdoor installations.
So here are a few tricks for a successful and creative final result. First of all you will need to select the right fixture for the application, below is a simple table explaining the most important differences on two of HARMAN’s Exterior Projection models.
|Exterior Projection 500||Exterior Projection 1000|
|Maximum lumen output||6.100 lm||16.800 lm|
|Cut-off angle||12°, 22°, 36° or 50° variants||10° - 44° (remote zoom)|
|Number of gobos||6 rotating/indexing gobos||7 rotating/indexing gobos|
|Color system||8 fixed colors||CMY color mixing system + 7 fixed colors|
|Animation effect||Horizontal left-right traverse||Continues rotation with variable angle|
|Size (l x w x h)||415 mm x 293 mm x 444 mm
11.6 in. x 16.4 in. x 17.5 in.
|702 mm x 417 mm x 618 mm
27.7 in. x 16.5 in. x 24.4 in.
Even though the Exterior Projection fixtures come included with a set of nice, standard gobos preinstalled in the fixture, often there is a need for creating custom gobos to fit with the overall lighting concept and maybe even to map the projected image to the building structure.
In order to support the design of custom gobos, Martin offers the “Line it up” gobo as a standard accessory with both of these projectors. This gobo is also included in Martin’s Exterior Projection demo kits.
The purpose of the “Line it up” gobo is to make it easier to design custom gobos by following this procedure.
- Install “Line it up” gobo in the fixture
- Place fixture in the exact position and projection angle to the façade
- Project the “Line it up” gobo on the façade
- Take a site photo of the projected image from a similar position as the fixture
- Import “Line It Up” artwork (.ai or .png) into a graphics program such as Adobe Illustrator.
- Use the information from the site photo and the artwork to design custom gobo in another layer.
- Send the custom design to a gobo manufacturer. Most gobo manufacturers will know the gobo requirements for Martin fixtures, however the requirements can be found in this table:
|Gobo Requirements||Exterior Projection 500||Exterior Projection 1000|
|Outer Diameter||30.0 mm +0/-0.3 mm (1.2 in. +0/-0.02 in.)|
|Maximum image diameter||23 mm (0.91 in.)||26 mm (1.02 in.)|
|Glass gobo thickness, minimum||1.1 mm ±0.1 mm (0.045 ±0.004 in.)|
|Glass gobo thickness, maximum||3.0 mm ±0.3 mm (0.12in. ± 0.012 in.)|
|Aluminum gobo thickness||0.5 mm ± 0.02 mm (0.020 in. ± 001 in.)|
|Suitable material||Borosilicate glass, coatings heat-resistant to 450°C (842° F)|
|Alternative material||Aluminum 1060, paint on front lens side, 450° C (842° F) HT paint|
Some gobo manufacturers include:
The "Line it up" gobo artwork can be downloaded as Adobe Illustrator file and .png file here:
Real life example:
Using the “Line it up” gobo, we can understand that in order to only hit the silo, the custom gobo must be black according to the grid information found in the image. In the specific example, the resulting custom gobo was used to highlight the structural elements of the building and to specifically illuminate the building, only avoiding any light pollution.
We thank you for reading and as always, appreciate your support. For additional questions regarding architectural lighting design with Martin products, please feel free to contact us.