Colorimetry Research Inc. CR-100 Colorimeter

Professional Colorimeter with big performance in a small size

The CR-100 is a professional colorimeter ($4,995 MSRP) from a new company, Colorimetry Research Inc. The all metal design is rugged and practical. What is likely to surprise most people seeing the instrument for the first time is how small it is. Resembling a telescopic sight, it is only 7 inches long, 1.5 inches in diameter, and weighs less than a pound.

Design
The CR-100 connects to a PC via USB, which also provides the necessary power. The data interface is rs-232, which operates over the USB connection using an internal usb/serial adapter and an in-house virtual COM port driver. It also includes a tripod mount with several mounting slots for placement flexibility.

The FOV is quite narrow. For example, when placed one meter from the target the spot size is only 4.3 inches (110 mm) in diameter. Since the instrument has no aiming mechanism this is a useful design choice. Given its small size and narrow FOV, most will find it quite easy to get a good aim point merely by line of sight. Colorimetry Research offers the CR-200, a version of the CR-100 with a configurable viewing port, but this adds another 15-20% to the price.

A calibrated cosine receptor/diffuser is available for an extra $390. Some may find this useful, but frankly the low-light sensitivity of the instrument is so good (more about this below) that having the ability to read directly from a projector lens would provide limited utility.

The colorimeter ships in a padded bag with a usb cable. The company's own in-house software is available as well, though most will probably opt for custom software, such as ChromaPure which provides support with v. 2.5.4.

There are three internal operating modes related to refresh rate detection and synchronization. The meter's sync feature can be turned off, entered manually, or set automatically when pointed at a 100% white test pattern displayed on the target display device. This is a particularly useful feature and no doubt contributes to the instrument's excellent repeatability, even at very low light levels.

Performance

The performance of a color analyzer is a function of four measurable criteria.

  • Colorimetric accuracy
  • Repeatability
  • Low-light sensitivity
  • Speed

Let's take a look at the CR-100 in each of these areas.

Colorimetric accuracy

I used the CR-100 to measure 8 displays using 4 different display technologies (LED, LCD, CRT, and plasma) in our lab and then compared the results with our JETI in-house reference spectroradiometer.

  White Red Green Blue
Largest error (x,y) 0.006 0.004 0.005 0.005
Smallest error (x,y) 0.000 0.000 0.000 0.000
Average error (x,y) 0.002 0.002 0.002 0.002

These are near reference results. Only the most exacting applications would require correction with a reference instrument. Colorimetry Research provides several built-in color correction matrices for different display types.

Repeatability

Measuring a plasma display with the CR-100 set to automatically detect and synchronize readings with the display's refresh rate (59.94 Hz), I obtained the following results after 15 consecutive measurements.

Video Black
 
x
y
Y
±
n/a
n/a
2.0%
5% Video
 
x
y
Y
±
0.0012
0.0011
1.39%
10% Video
 
x
y
Y
±
0.0003
0.0004
0.40%
20% Video
 
x
y
Y
±
0.0002
0.0004
0.13%

Again, these are reference results. Clearly, the sync feature works very well.

Low-light sensitivity

The ability to accurately and quickly read very low light levels is perhaps the most attractive feature of tristimulus filter-based colorimeters. It is also one of the most difficult features to test. More often than not, the instrument's performance exceeds the precision of the display technology used for the test and you end up measuring the limitations of the display rather than the measuring tool.

For example, I first attempted to use the CR-100 to measure video black on my Pioneer Kuro 9th-generation 5020 plasma, which is renowned for its unmeasureably low black level. I soon discovered that my display's black level was not stable (it may have been at one time, but I have been using it daily for several years, and its performance may have degraded with use). In fact, after receiving only a video black signal the Kuro's output took several seconds to settle down, and then would rather quickly go completely black. However, I got consistent, repeatable readings of 0.0014 cd/m2 before the screen went black. In frustration, I decided to try the same experiment with a JVC front projector, also known for its very low black levels. However, in this case the test was compromised by the tiniest amount of light in the room, such as my laptop monitor, which would elevate the luminance reading off the screen (which is, after all, designed to reflect light efficiently). Lacking the patience to turn my projector room into a black hole, I decided to go with the stable, though fleeting, Kuro reading of 0.0014 cd/m2.

Throughout all of my tests I never encountered a signal so low that the CR-100 could not reliably measure it. Whatever its merits as a colorimeter, the CR-100 is also undoubtedly a world-class photometer, significantly outperforming what used to be the gold standard in this area, the Minolta LS-100.

Speed

To test the speed of the CR-100, I generated an automated suite of 100 test patterns from an AccuPel DVG-5000 that ChromaPure would read and then record. I also ran this test against the X-Rite i1 Display Pro and the Klein K-10 for purposes of comparison. In addition, I ran through one pass of the the Lumagen 125-point LUT using each colorimeter to provide some-real world comparisons and then extrapolated the time required for a 729-point LUT and a 4913-point LUT.

 
K-10a Colorimeter
Matrix Size
125
729
4913
Minutes to complete *
3
13
90
 
i1 Display Pro **
Matrix Size
125
729
4913
Minutes to complete *
6
28
194
 
CR-100 Colorimeter
Matrix Size
125
729
4913
Minutes to complete *
3
13
90
* This includes only the time required for the matrix to complete. Pre/post-calibration test patterns and grayscale/gamma calibration is not included.
** The i1 Display Pro can run faster by setting the meter to a shorter integration time, but doing so compromises repeatability.

The most interesting aspect of this comparison to me is that the speed of the K-10a and the CR-100 were essentially identical. A display test pattern-return reading cycle requires about 0.6 seconds for each colorimeter. This suggests that the speed of each instrument is limited not by the instrument itself, but by the rs-232 interface both use.

Among color analyzers, the K-10a has always been the speed champion. The CR-100 is not faster than the K-10a, but it is obviously no slower. The speed of a colorimeter used to be merely a matter of convenience, but with the advent of popular and affordable options for 3D LUT calibrations requiring hundreds or even thousands of measurements, the speed of the measuring device becomes a much more important factor.

Summing up

As you can probably tell I was immensely impressed with the CR-100. It achieves a combination of performance milestones that place it at the zenith of commercially available professional colorimeters.

I do have a few minor quibbles. Installing the driver in Windows 8 is an annoyance because the driver is unsigned. However, Colorimetry Research is working on this issue and may have fixed the problem before this review appears. Also, although it costs less than its only real competition—the Klein K-10a—the cost of adding an aiming device and a cosine receptor (the K-10a includes both) all but eliminates the price advantage. Finally, as long as I am picking nits I would have preferred a carrying case over a padded bag and a longer USB cable.

However, when it comes to performance I cannot find any reason to criticize the CR-100. It is the best professional-quality instrument to come along in several years. Colorimetry Research has also just released a reference spectroradiometer, the CR-250, which I will review in the next few weeks.


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