LED – standard color viewing light

Why doesn’t GTI offer any LED color viewing light sources?

LED-color viewing light might be the future but it is not the present!

Lately we have been asked why we don‘t offer any LED color viewing products. For that reason we have decided to make this statement.


LED is not ready for critical color viewing
We do have LEDs and are testing them extensively. We have come to the conclusion that we cannot simulate a perfect D50 or D65 spectral energy curve with today’s LEDs. We can influence the typical LED curve but the result is not yet satisfying.


Standard color viewing conditions are not easy to meet – especially with LEDs.

We have been developing lamps with the best possible match to the D50/D65 spectral curve for many years. That is very difficult with fluorescent lamps, which is no secret in the industry. Until today, no manufacturer of color viewing products has been able to match the D50 curve perfectly.

With different spectral energy curves the color is rendered differently, even if the aim point in color space is the same. That shows that we have to work with some existing problems – LED light sources are not better, just different! So, why adding more problems?


Continuity is important!

We at GTI have been developing and producing standard color viewing products for almost 40 years for all kind of applications, and continue to do so. For us it is important that the prepress personnel see the same color values as the pressman at the printing press, and that the lab sees the same as the production person. The high cost LED color viewer can’t be produced for larger color viewing applications. This could interrupt the continuous chain of similar color viewing products in any company. That doesn’t make any sense.   

LED: the bottom line – it’s not economical!



  • LEDs are using less energy and are more economical and they don’t require the lamp change every 2,500 hours. Within 20,000 hours that LED should run without problems, while we have to replace the fluorescent lamps 8 times. This will create maintenance costs of about € 800 within about 4 – 6 years.
  • The energy consumption of LEDs is much less than with fluorescent lamps. Unfortunately, I don’t have any reliable date to compare the usage of a LED unit with a conventional color viewing booth. A unit with fluorescent lamps uses 38 Euros of electrical energy during the 20,000 hours of use!


  • The cost to run a conventional unit for 20,000 hours is about 840 Euros, the additional cost of a LED unit is over 2,000 Euros – that is not economical.
  • After 20,000 hours the LED unit has to be returned to the factory for reconditioning and calibration – we can only speculate how much this would cost! With our fluorescent lamp products you just change the lamps and clean the viewer and you are good for another 2,500 hours of use.
  • With LED technology the warm-up phase has not been reduced or eliminated. LEDs need also about a 20 minute warm-up period to reach an optimal temperature.
  • LEDs produces heat. This heat needs to be controlled with electrical fans. Fluorescent lamps together with modern, electronic ballasts produce very little heat and that can be controlled be simple ventilation openings.


Why change a technology?

Fluorescent lamps have proven over many decades that good color matching is possible. The lamps are available in 6 different sizes and are in use worldwide. We would introduce a new technology only when we have something better to offer. LEDs are at the present state only different, but definitely not better!    

Some lighting situations cannot be simulated with LEDs

It could be interesting to change to different light sources or influence the spectral energy curve of a light source, but in the graphic arts we have an international standard ISO 3664-2009 and this standard asked for D50 light and D50 only! Any other light source can cause complications in the process! 

In all other industries, different standards required. As per the standard, color viewing is done with D65, the artificial daylight source. Furthermore, there are the home light Incandescent A, as well as store light TL84, TL83 or CWF as required. The spectral curve of these light sources cannot be simulated with LEDs at the moment. Why do we need a new complicated, expensive technology if we can’t meet the standard requirements?