Questions and answers about gobos

We have taken the trouble to make the questionnaire as comprehensive as possible. If you still have questions, please do not hesitate to contact us.

1. What is a gobo?

Gobos were developed for use in high-performance projectors. Due to the high heat resistance of gobos, they can be used in almost any projector such as moving heads or profilers. Gobos can be produced in different sizes for a specific type of projector.

2. What kind of gobos can we make?

We have specialised in the production of customised glass gobos and manufacture everything from b/w to colour and multicolour gobos for almost every common type of device.

3. How is a gobo made?

We produce our glass gobos with a laser. This process has many advantages. It saves work, is fast and reliable. In addition, very high resolutions are possible with the laser. The digital output of the template makes it possible to guarantee high repeat accuracy with consistent quality.

4. What is a line drawing and what is a greyscale? PHOTO MISSING

A line drawing consists of areas and lines without gradients and 3D effects.

Grey scale represents gradients and shading. Greyscales are created in gobos by rasterisation. A halftone consists of an arrangement of fine dots.

5. What templates do I need to make a gobo?

For the production of gobos we need printable vector data or high-resolution pixel formats.

Pixel formats should have a resolution of at least 600dpi at 15cm image width or height.

6. What do "positive" and "negative" mean?

Positive means in most cases:
white background (light), with black motif / lettering

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Negative means in most cases: 
black background, with white motif / lettering

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7. Can a gobo represent my individual layout 1:1?

Unfortunately not always. Individual motifs with too much filigree or motif content may be difficult to realise on smaller gobos.

In the area of multi-colour gobo/rastering and also line drawings, a minimum size must be given so that the motif can still be displayed well. However, the feasibility of the respective motifs for the desired lamp type is always checked in advance.

8. What kind of motifs can you depict with a gobo?

Almost all motifs can be realised as a gobo if the template can be adapted for a gobo production and if the realisation makes sense after testing.

9. What is the resolution of a gobo?

Stroke templates are usually output in vector format with a line width of approx. 0.008 mm-0.012 mm.

The font height of motifs should not be smaller than 0.5 mm to ensure a clean display.

A raster is output as a bitmap with a resolution of 2400 dpi to 3000 dpi.

Higher resolutions on request.

10. What colours can you display with a gobo?

All standard colours from the dichroic colour palette can be displayed.
Colours that are not included in the colour palette can, depending on the colour tone, be produced by a 2+colour mixture or CMYK mixture.
Due to the strong white contrast in a projection, the colours should be rather dark. Subtle colours and gradients may not be perceived well or have a good effect due to the contrast.
With a CMYK mixture, multi-coloured and even photorealistic gobos can also be created.

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PANTONE / HKS / printing inks:
Printing inks cannot be implemented exactly matching.
The dichroic colour palette corresponds to an own colouring which is not matching to the common printing inks.

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The colour representation in the projection is influenced by many factors.
There are too many influences to guarantee an exact colour representation.

  • Colour of the dichro filter
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  • Colour temperature of the light source
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  • Power of the light source
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  • Distance of the projection
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  • Colour of the projection surface
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  • Ambient light
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  • Contrast
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  • etc.
11. What are the sizes of gobos?

Almost every projector has its own gobo size. Gobo sizes range from 12.5 mm to 105 mm.

We can produce gobos from 20 mm with our grinding machine. We have smaller sizes in stock for common projector types in b&w.

12. Do you also deliver abroad?

We deliver our gobos to all countries to which our logistics partner UPS delivers.

13. What do I need to order a Gobo?

We need:

  • Information on your device types (manufacturer / model / gobo size, if applicable),
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  • a printable template
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  • figures
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  • Statement of projection type (front/back projection)
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  • Invoice/delivery address
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Use our request form.

if required.
14. How long does it take to produce a gobo?

We need 2-3 working days plus shipping for standard payments and depending on the complexity of the production of the gobos. Express orders are usually possible without surcharge, but it should be clarified with us whether an implementation is possible at short notice.

15. How should I treat a gobo?

Gobos are very sensitive due to the material (glass). A gobo should therefore always be protected from mechanical influences. After use, clean the gobo with petroleum ether, acetone or ethanol. For coloured gobos, the cloth must not be wet. Excessive liquid may penetrate the gobo and leave residue.

16. How do I install a gobo?

As there are different types of installation, please refer to the operating instructions of the unit.

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Only the installation direction of the gobo must be done according to our specifications.
An instruction is enclosed with every gobo delivery.
The installation direction changes depending on the type of gobo.

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Incorrect installation could destroy the gobo

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17. What is the best way to store a gobo?

Always store gobos in a dry place, preferably in our gobo box in which the gobo was delivered.

18. Can you make gobos for each lamp?

For most moving heads, scanners and profilers this is no problem. We will be happy to check whether a production is possible for your device.

19. What is an adapter ring and what do I need it for?

We use adapter rings for gobos for profilers.
For some sizes, a glass gobo can also be made to fit a metal gobo holder.
In addition, the adapter ring protects the glass gobo from being scratched by the gobo holder.

20. Can gobos break?

The materials are so sophisticated that no damage will occur if they are used properly. However, there should be no fingerprints or other substances on the gobo that could be ignited or burnt in by the heat. Since the support material is glass, it is important to avoid dropping it.

A b/w gobo can withstand a temperature load of up to approx. 530°C (with adapter ring up to 300°C).
Coloured gobos can withstand a temperature load of up to approx. 300°C in peaks.

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It is essential to ensure that the setting of the light source is always correct.
A gobo must not be operated with a setting in the hotspot.
A light cone that is not optimally set can cause the gobo to burn or break in seconds.

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21. Why can't I get my gobo properly focused?

Optics 1
If the gobo cannot be focused, this may be due to the optics. The manufacturers always specify a maximum image size for the gobos to be used. This size cannot be fully utilised for projections with fonts, for example. Usually you have the effect that you can focus the inner area or the outer area, but never both equally sharp. Depending on the quality of the optics, often only 50% of the image area can be used to ensure a clean focus or projection.
 
Optics 2
It is rarely possible to align the lamp 100% parallel to the projection area. This results in distances of varying lengths to the projection surface that the optics cannot compensate for. This can lead to partial blurring.
 
Plane optics
With 2-colour and multicolour gobos, one layer/colour lies at a distance from the next colour. The distance between the layers is only 0.55 mm. The optics cannot compensate for this distance. As a result, only one layer of two can be brought into focus.
&Uml;usually, the b/w layer is brought into focus, as this serves as a mask.

22. Why do I have light reflections and shadows in my projection?

Glass gobos are made of highly reflective material. This property is needed to withstand the enormous heat generated. This advantage is also the disadvantage. The high degree of reflection creates an endless reflection between the gobo and the focus optics. High-quality optics are anti-reflective to counteract this negative effect.

23. Why do I have coloured edges in the projection with a b/w gobo?

Light (white) consists of several wavelengths (mostly coloured).
The light is refracted at the edges of a motif and no longer takes a linear path.
This results in a prism effect, which often has the effect of yellow and/or blue shades in a projection. Depending on the quality of the optics, this can be more or less pronounced.

24. How can you compensate for distortion in a projection?

The distortion or de-skewing of a motif for a projection is very time-consuming and depends on many factors, so we have decided to no longer offer this.

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