Frequently asked questions

Projectors

• What is the service life of an LED?

  The service life of an LED light source depends on numerous factors, including the operating temperature. An LED loses brightness over the course of its service life. The technical data includes the L70 value, which indicates the number of hours after which the brightness of the LED falls below 70 per cent of its initial value. The projector remains functional even after this time.

• Why do LED projectors require cooling?

  LEDs (light-emitting diodes) consist of semiconductor materials that must not be heated in the same way as the filament in an incandescent lamp. The service life and brightness of an LED decrease when the operating temperature exceeds a certain limit. Efficient cooling therefore guarantees the reliability and luminous intensity of a projector.

• Is a projection suitable for continuous operation?

  Our projectors are designed and tested for 24/7 use. This means they can be operated without interruption. The projection motifs (gobos) made of heat-resistant glass and mineral colour filters are durable and do not fade. With 8 hours of daily use, the LED light source has a life expectancy of approximately 12 years before its brightness drops to 70% of its initial value! You can have the LED light source replaced by our customer service team.

• What is the expected lifespan of a Derksen projector?

  PHOS projectors have a life expectancy of at least 35,000 operating hours before the brightness of the LED drops to 70% of its initial value. With an average daily use of 8 hours, this equates to a duration of approximately 12 years. Even after this time, the projector can still be used and it is possible to have the LED light source replaced by our customer service team.

• Are PHOS LED projectors silent?

  The lower power ranges of our PHOS LED projectors, PHOS 15 – PHOS 25, are passively cooled and therefore completely silent. Projectors with higher output, PHOS 45 – 160, use a very quiet fan.

Projection motifs

• What is a gobo?

  A gobo is a metal or glass template that is placed in front of a spotlight to project an image. The gobo carries the projection motif. Derksen manufactures gobos from specially coated glass with up to 4 colours (CMYK screen). All gobos are durable and do not fade.

• How are projection motifs produced?

  Derksen manufactures customised gobos based on digital data provided by customers. The data is checked and processed for use with a high-performance laser. The motif is then engraved with extreme precision into specially coated glass. Depending on the number of colours in the motif, this process is repeated up to four times.

• How can a distorted image be corrected?

  A distorted projection is caused by an oblique angle between the optical axis of the light projector and the projection surface. If the projector cannot be aligned at a right angle, it is possible to pre-distort the motif on the gobo so that the result appears straight. Derksen offers keystone correction as an additional service.

• Can I also use transparencies or slides in gobo projectors?

  Colour-printed transparencies or slides made from film material are not suitable for use in Derksen projectors. The carrier material and colours are not durable and are quickly destroyed by the energy of the light. Films or slides even pose a safety risk, as unsuitable material can ignite when placed close to the light source. Glass gobos can be used without risk and are durable.

Environmental conditions

• Are projections also visible in daylight?

  Outdoors, projections remain invisible in sunshine or cloudy skies. The sun is a superior light source. Daylight overpowers any artificial light. In an indoor space with windows, the situation may be different in daylight: it is necessary to check whether the power of a gobo projector is sufficient.

• What affects the visibility of a projection?

  The visibility of a projection to the human eye depends on: 1. Output power of the projector, 2. Brightness of the ambient light, 3. Distance, 4. Focal length of the lens, 5. Colour and texture of the projection surface, 6. Colour of the projection motif. In difficult situations, a test setup is required.

• What colour should the projection screen be?

  A projection screen should be white if accurate colour reproduction is important. Coloured projection screens can also be very attractive when black and white gobos are projected. In any case, light colours are better than dark colours for achieving high-contrast and bright images.

Company

• Does Derksen also manufacture digital projectors?

  No. Derksen Lichttechnik specialises in analogue projection technology and distributes its products in more than 36 countries. The particular appeal of analogue gobo projection lies in its tranquillity and simplicity. In today’s world, there is an overwhelming abundance of information and rapid visual stimuli.

• Are Derksen projectors manufactured in Germany?

  Yes. All projectors are assembled in Gelsenkirchen, in the heart of the Ruhr region. The aluminium and steel housing components are produced by suppliers in Germany. We source electronic components such as cables, fans and LED drivers from international manufacturers that comply with high European safety standards.