JETI Specbos 1201/1211 Reference Spectroradiometers

At some point many professionals conclude that their work requires a reference color analyzer. SMPTE has established standards for such a device. It must measure color accurately to within ±0.002 xy at or above 10 cd/m² and luminance accurately to within ±0.5 cd/m² for white field measurements. These are very exacting specifications that no tristimulus colorimeter can achieve, at least for chromaticity. For this level of accuracy you must have a 5nm spectroradiometer.

Unfortunately, such devices are not cheap. The Photo Research and Minolta reference devices start at about $15,000 and go up to near $30,000. The X-Rite i1Pro is reasonably affordable, but it is a 10nm device that cannot routinely achieve ±0.002 xy accuracy. Furthermore, in addition to being expensive, true reference devices also often suffer from practical limitations. They can be slow and have problems with low-light readings.

Recently, a German company JETI Reference Instruments has developed two true reference spectroradiometers, the Specbos 1201 (also known in the U.S. as the Orb Optronics SP100) and the Specbos 1211, that solve most of these problems.

First, they are relatively affordable, that is at least what passes as "affordable" in the context of reference devices. Second, both are reasonably fast for higher luminance sources, and the 1211 is speedy even with low luminance sources. They are also amazingly compact and portable and both include a nifty laser spotter that allows for accurate aiming. The only feature these incredible devices give up to the established Photo Research and Minolta competitors is stand-alone operation. The Minolta and Photo Research alternatives allow for aiming through optical sights and readouts on a small LCD screen. They are fully functional devices without a PC. In contrast, the JETI devices work only when attached to a PC via USB with custom software.

Both units share a similar design and software support. Both achieve reference levels of accuracy. The differences? Well, the 1211 is larger than the 1201 and about 30% more expensive. But surely the most important difference is low-light sensitivity. The 1211 is MUCH more sensitive than the 1201. At light levels at or above 50 cd/m² (14.6 fL) they perform similarly, but as you go lower than this the 1201 begins to take noticeably longer and longer to return a reading. At 4 cd/m² (1.2 fL) the 1201 will take approximately a minute-and-a-half to return a reading. By way of contrast, at this level of stimulus the 1211 chugs happily along returning a reading in about 5 seconds.

This has profound implications for day-to-day use. For this reason, the 1201 is best used for color management, when light levels are generally high, or as a reference device employed to create an offset for a field colorimeter, such as the Chroma 5 or Hubble. The 1211, on the other hand, can be used as a working color analyzer. Its speed and low-light sensitivity make it suitable for any calibration task—except perhaps reading black level—where the light level is so low even the 1211 often cannot cope. Fortunately, very low light levels can be accurately read with quite inexpensive instruments, such as the AEMC CA813 illuminance meter. The Chroma 5 will read down to about 0.01 fL, and the Hubble will read down to 0.001 fL.