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Monaco EZcolor 2.6 & Optix XR Review
Calibration and Profiling of your Monitor
All photographers who like to print their photos or share them on the web should strongly consider calibrating and profiling their system. This helps ensure consistency between what is seen on the monitor and what is seen on other people's systems and in your prints. Several programs and hardware tools exist to perform this calibration and monitor / printer profiling — this article looks at the steps involved in using the Monaco EZcolor 2.6 + Optix XR.
This article is a preliminary overview and it will be amended with more quantitative results later.
Another article will look at the use of this application to profile both the scanner and printer.
Monaco EZcolor + Optix XR
Monaco (acquired by X-Rite in 2003) provides a number of calibration and profiling options, both hardware and software. One of the more affordable and popular products for the serious photographer is the Monaco EZcolor 2.6 software combined with the Monaco Optix XR colorimeter.
The OptixXR colorimeter (aka DTP94) is a small black USB device that is designed to hang over the edge of your CRT or LCD display, measuring the underlying tristimulus values from a large color patch displayed on your screen. The Monaco EZcolor software allows you to calibrate your monitor and then generate ICC color profiles for your monitor, scanner and printer.
Unlike software-based products such as Adobe Gamma or QuickGamma, EZcolor uses the external hardware sensor to facilitate optimal calibration and accurate profiling. Visual calibration (i.e. without an external sensor) is often not very good, as your assessment of color will be greatly influenced by your immediate surroundings. The profiling process must be precise and absolutely must require the use of an external colorimeter device. The EZcolor program first offers the standard profiling of your monitor, but then also provides a mechanism to profile your printer / paper / inks in addition to your scanner.
The ability to create printer profiles in the same package was the primary reason I selected Monaco's product over the other competitive alternatives. At the time I don't believe the other (affordable) solutions provided these other profiling options.
You might be wondering how it is possible to profile a scanner or printer with only a display colorimeter. The package includes a 5"x7" reflective reference target (IT8.7/2), which you scan into your computer. The software's interpretation of the scanner's output allows the scanner transfer function to be calculated (and a profile generated). When you are later instructed to print an IT8 target from within the package, the dried printer output is then scanned and the software works backwards to determine what the printed output must look like. Knowing this and the original IT8 reference data, the printer's transfer function can be calculated (and a profile generated). Some people question this approach to profiling a printer, but the results have been extremely good for me and countless others. Note that there certainly is a dependence on the quality of your scanner, however — more on that later.
While the bundle wasn't cheap (retail U$498), I was able to use a significant discount that was offered with my NAPP (Photoshop Users Group) membership. It seems that there are now a few places that are selling the bundle online for U$249, presumably because the new Optix XR2 is available.
Preparations for Profiling
Calibrating and profiling your display takes no more than about 5 minutes, and most serious photographers will redo the process every month or so. Profiling your printer takes longer (requires a long drying phase), and should be done any time that you replace your ink cartridges or start with a new paper stock or printer.
How often do you need to calibrate your monitor?
How often you calibrate your CRT monitor is somewhat of a subjective choice, but typical guidelines suggest weekly if you are serious about color management, but once a month is a pretty common choice for hobbyists. The dyes used in LCD panels don't suffer the same degree of shift as do the phosphors in a CRT display, and you are generally only affected by the change in the backlight lamp over time, so calibration may not be required as frequently.
Clean the Monitor and Warm-up
If you turn on the lights in your room, and turn off your monitor, you should easily see any finger prints or smears on the surface of your display. Performing a calibration and/or profiling of your monitor with an external device such as the Optix/XR may cause inconsistent readings if the surface is not clean.
If possible, use a screen cleaning solution and cloth to spray and wipe down the surface. Absolutely DO NOT use Windex (especially if it contains Ammonia) as you can end up stripping off the anti-glare coating of your monitor. In my case, I use ScreenClean by MONSTER, which came with both a spray bottle and a thick lint-free cloth.
Before proceeding with the monitor profiling and calibration process, ensure that your monitor has been on (i.e. not screen-saver power-down mode) for at least one hour. This will ensure that the monitor's color output has normalized and will be representative of general conditions.
In addition, it is very important that the resolution and refresh rate have been set to your standard operation conditions. Changing resolution and/or refresh rate will affect the brightness. Your monitor's geometry settings (pincushion, keystone, etc.) also have some limited effect on the resulting brightness, so these should be left alone once the monitor is calibrated.
Reposition the On Screen Menu / On Screen Display (OSM / OSD)
Most monitors provide an OSD to allow visual feedback for changes in the brightness, contrast, RGB adjustments and many other options. This is an overlay that is drawn over top of your normal monitor output. By default, the OSD is almost always displayed in the center of the screen. For the purposes of monitor profiling and calibration, this is not an ideal position! You will be asked to adjust the RGB outputs of your monitor to match the suggestions from the Monaco EZcolor software, and it is very likely that you will use the center region of your display for the Monaco sensor region and feedback recommendations. Displaying the On Screen Display in the region where the OptixXR is currently taking a measurement will throw off your readings and lead to an inaccurate result.
Therefore, I strongly recommend that you move the OSD to a region near the edge of the display (e.g. lower right). Unfortunately, not all monitors allow you to reposition this menu, but my Mitsubishi 930SB provides this option in the last tool menu on the right, second sub-option "OSM POSITION". I repositioned mine to the lower right.
If you are unable to reposition the OSD, then you will need to turn off the OSD after every time that you made an monitor adjustment, allow the readings to stabilize (five seconds or so) and then assess the software's feedback.
Remove Adobe Gamma Shortcut
If you have instlled Adobe Photoshop, then it is very likely that Adobe Gamma Loader has been added to the list of programs that automatically run when you boot your computer. Adobe Gamma is a very basic monitor calibration tool that is included with Photoshop, that relies on visual calibration by the user — a method that is quite unreliable.
|Removing Adobe Gamma from the Startup Folder|
Since you are now running a much more advanced calibration and profiling tool, it is important that you remove Adobe's tool first, so that you don't end up with competing monitor adjustments. You don't need to uninstall or delete the Adobe Gamma utility, but you should simply remove the shortcut from the Startup folder. For most people, this means looking in: C:\Documents and Settings\All Users\Start Menu\Programs\Startup.
Either delete the shortcut (you can easily recreate it later) or move the shortcut to a different folder, such as StartupNo. Windows XP only uses the specially-named folder Startup for loading boot-time software.
Monaco EZcolor 2.6
Launch Monaco EZcolor 2.6. Select "Create Monitor Profile"
Note that the program takes over full-screen with a grey background. This is to avoid any distraction or bleed from other colors. This is particularly important if you are using visual calibration, rather than instrument-based calibration.
Plug in the Optix XR into a USB port, but not on a hub with other devices, if possible (this will provide a more accurate reading). X -Rite DTP94 recognized. Windows XP comes up with a warning message: "X-Rite DTP94 has not passed Windows Logo testing". Since the Windows Logo certification is a voluntary program, not all vendors have chosen to participate. The Monaco drivers haven't been updated in ages, so it's quite likely that you'll see this warning. Continue anyway.
Now, adjust your room lighting to your typical viewing conditions. In other words, turn on the lights that you would usually have on when viewing photos on your computer. Have the same number of lights on and same intensity as usual. This helps ensure that your created profiles are representative of normal environmental conditions. Your surroundings play a significant role in your perception of color and changes, such as the addition of more light to the room, will reduce the effective gamut produced by your display.
As there is a layer of glass between the colorimeter and the underlying phosphors, it is possible to get a "bleeding" of light from ambient sources that are picked up by the sensor. Therefore, it is best to avoid very bright light sources in your room. This is also the reason why it's important to have visual elements (such as the On Screen Menu) far away from the sensor region. As an aside, I don't see any significant (> +/- 0.05 cd/m^2) difference in the luminance measurements when I turn on/off my room lights.
Optix XR2 Improvements
Note that this article assumes that you are using the original OptixXR. X-Rite has released a follow-on device, the OptixXR2 which includes a feature called "Automatic Display Control" (ADC). This feature presumably removes the need for the user to modify monitor controls and instead uses communication with the monitor directly to complete and optimize the calibration process. The Optix XR2 also provides a diffuser for ambient light measurements, which should help in determining the appropriate adjustments for environmental conditions.
Calibrate & Profile
Set Monitor Type to either CRT or LCD. Not all software/hardware packages can accommodate LCD displays, but the EZcolor + OptixXR is designed to handle both. Unless you are willing to spend a lot of money on an EIZO LCD display, a bulky, space-hogging CRT is still the best choice for a color-managed environment. In my case, I am working with a Mitsubishi 930SB CRT , so I select CRT and then Next.
Calibrate the MonacoOPTIX XR by placing it on a flat surface. A black foam surround under the DTP94 sensor ensures that light leakage is minimized. Click on "Calibrate".
A few seconds later, you are asked to select the profile parameters — White Point and Gamma. Unless you are working in a newspaper / desktop publishing environment (where 5000K may be more appropriate), you are probably going to be interested in a White Point (Color Temperature) of around 6500K (degrees Kelvin). The available options include: 5000, 5500, 6500, 7500, 9300.
The selection of White Point is a personal choice, and it is an excellent example of where the human visual system (HVS) is capable of altering your perception of your surroundings in significant ways. The most readily apparent of these is chromatic adaptation. Chromatic adaptation is the process whereby you automatically perform the equivalent of a digital camera's Auto White-Balance. Your brain is able to remove the color cast associated with the result of different environmental illuminants. Changing the White Point of your monitor to 5000K from 6500K will immediately cause all visual elements to appear very warm (orange-red), while changing from 6500K to 9300K will cause all elements to appear very cold (blue). If you leave the display at either setting for a period of a few seconds, you will easily adapt to the new White Point and discount the transitionary color cast that appeared. For the purposes of the monitor calibration, it is best to select a White Point that is representative of your viewing environment.
Gamma options include 1.8 and 2.2 For PC displays, a gamma of 2.2 is typical. Mac displays are often set for a gamma of 1.8 for historical reasons (an attempt to produce an equivalency with the dot-gain response of printed output). Gamma defines the exponential response curve of the output intensity for a given input. A gamma of 1.0 would mean that the intensity was linearly proportional to the input voltage. The relationship between the output strength of the CRT's electron gun and the visible light intensity from an excited phosphor is exponential. Most phosphors have a response that is equivalent to a gamma exponent of 2.2. It should be clear that a linear sequence in monitor input signal will result in a non-linear monitor output (luminance).
Obviously, software applications want to operate in linear terms, and would like to drive a linear intensity sequence of 0 to 255 and have this produce a roughly linear luminance output on the display. So, the video card is configured to perform the inverse of the phosphor's exponential response curve prior to sending the image to the monitor for display. If the linear input (RGB in the computer's view) is raised to the power of the inverse of the gamma exponent, and then the phosphors effectively raise that output to the power of the gamma exponent, the net result is a linear response in intensity out of the monitor.
The goal behind an optimum gamma selection is that a black-to-white gradient displayed on your monitor (with no color profile active) should show little or no banding in the shadows or three-quarter tones. Unfortunately, since the lookup tables (LUT) within most video cards only provide an 8-bit precision, it may be hard to avoid some amount of posterization. Ideally, you'd select a gamma somewhere between 1.8 and 2.4 and would do this by displaying a raw black-to-white gradient strip across the monitor. Increase the selected gamma and look for banding. If banding appears, drop the gamma setting and re-assess.
Adjust White Point
This screen allows me to calibrate the gain of the CRT monitor's individual RGB outputs to best achieve the target white point.
An image of the Optix XR is drawn within the dialog box as a guide for where you should place the sensor. The taget white point tempterature is displayed, along with the chromaticity target coordinates (X & Y) that define the desired white point. In my case it reads:
|Target||6500K x=0.314 y=0.324|
At this point I lower the sensor over the image (it is important that it line up so that the small sensor can be completely surrounded by the color regions that will be displayed later). A heavy metallic piece is attached part-way along the USB cable, and this is draped across the top of the monitor to allow the OptixXR to sit at whatever height and position on the screen you want.
Click on "Measure" and then a series of primary colors are displayed within the sample region (R,G,B,White). A few seconds later, the Target and Measured white points are shown, along with the lumiance (cd/m^2) and three color bars that show where your monitor is relative to the target whitepoint.
A beep sound will be produced for every measurement that has been made (roughly once a second), allowing you to determine whether or not a given reading has stabilized or not (useful if you didn't reposition the On Screen Menu).
At this time, I select a Custom Preset on my monitor via the OSM, which I will use for the color gain adjustments. Even though my CRT has a "sRGB" mode preset, I do not use it. Given the existence of a "Custom" color mode preset and an external sensor (such as the Optix XR), one should not use the monitor's sRGB mode preset.
Using the Custom color mode, I adjust the monitor's individual RGB settings until the orange pointers line up with the middle of the red, green and blue bars. You'll note that it may be easiest to do this by eliminating one of the three variables:
- Set gain for Red to 100.0%
- Increase or Decrease gain for Green (until the orange arrow is in the middle of the green bar)
- Increase or Decrease gain for Blue
Once you click on Done, the final measurements are shown. I often record these, as I'd like to have some way of observing monitor drift over time.
Why set the Black Point?
The goal behind setting the black point for your monitor calibration is to create a very slightly-visible transition from real black (RGB=0x000000) to the darkest gray that can be output (RGB=0x010101) . With my monitor calibrated, I am able to visually distinguish level 1 from level 0. After calibration, most monitors should allow you to distinguish level 6 from 0 or better. If you can't distinguish between level 0 and levels as high as 10 or so, your black point is likely too low and needs to be raised. This type of black point test can be easily accomplished in Photoshop by drawing a fullscreen black background (RGB=0x000000) and then overlaying a rectangle drawn with intensity level 1 or higher. In order to ensure that the monitor's profile is not affecting the results, Photoshop needs to "Preserve Color Numbers", which is accomplished by selecting View->Proof Setup->Monitor RGB. Clearly, the Monaco package (when combined with my monitor) did a great job at setting the black point for me.
Measure Lightest Black
Adjust contrast to 100%, brightness to 100%, then click on Measure. Four measurements are done (R,G,B,White)
Measure Darkest Black
Set brightness to 0%, or "until the application window and controls are just visible". On most newer monitors, you should still be able to read the user interface elements even while the brightness setting is at 0%. However, an old monitor may have phosphors that are no longer producing the same quantity of light and a level of 0% might be unusable. With my monitor set at 100% contrast and 0% brightness, I am easily able to use all applications without any difficulty reading UI elements, while I would have a harder time working with photographic images.
Clicking on "Measure", three readings are then performed with a solid black sample.
Clicking on Measure starts up a continuous measurement with graphical feedback of the monitor's current output levels versus the suggested target.
With my 2 year-old display, the adjustment resulted in a brightness setting of 71.5%. As always, you need to wait for about 3 consecutive measurements after any monitor change before the sensor readings stabilize.
Evaluating the Highlights
In a similar manner as for the black point, I was interested in seeing what the calibration did to the rendition of highlights on my monitor. Again, in Proof Setup->Monitor RGB, creating a full-screen fill with RGB=0xFFFFFF (white, level 255), I drew a rectangle with 0xFEFEFE (lightest gray, level 254). I was not able to discern these levels, but could see the difference between level 253 and level 255. So, in effect, the highest level gray will be essentially "blown-out" as far as perception goes. Losing only a single level at the high end is extremely good, again, a testament to the quality of the calibration from the Monaco setup and my monitor. Of course, I could have probably re-done the "Set Brightness" stage and targeted the orange arrow one step lower than I had. This may have brought down the intensity of output level 254 so that it could be distinguished from level 255, but it is possible that this could have pushed level 1 down enough that it couldn't be discerned from level 0.
Measure Color Patches
Click on Measure. A series of 35 color samples are shown and automatically measured by the Optix XR. These color samples are made up of 8 shades of each primary color (red, green and blue), followed by a white-to-black gradient series.
Internally, the EZcolor software created a Matrix-LUT (Lookup Table) ICC profile that maps input RGB values to the resulting XYZ coordinates for each of the tested patches.
The results from my profiling run were:
|White to Black Tones|
With the above series, it is a very simple matter to interpolate any given RGB value from the three orthogonal axes. There is also a close correlation between the White-to-Black tones and the sum of the Red+Green+Blue tones of the same intensity.
Displays the black and white luminance measurements:
|Target White Point||6500K x=0.314 y=0.324|
|Black Luminance||0.21 cd/m^2|
|White Luminance||100.32 cd/m^2|
Click on "Create Profile..."
Select a location and name for the ICM profile that is generated for your monitor. By default, ICM profiles are stored within the directory: C:\WINDWOS\system32\spool\drivers\color\
I prefer to create the profile including the output device type and model (e.g. "Monitor-Mitsubishi-930SB.icm"). There is very little value in including the date in the filename as it would simply clutter up your profiles directory, since you don't ever need to roll-back your profile to an earlier date. If this is a re-profiling of your monitor, resave over the older ICM file.
Once you've saved, you're brought back to the main menu, where you may decide to then create a Scanner or Printer profile.
Monaco Gamma at Startup
Now that you've calibrated and profiled your monitor, you'll notice that upon restarting your computer, the Monaco Gamma utility loads up and your screen's intensity may change. Even though you have set your monitor's profile as active within Windows, the gamma curve still needs to be loaded into your video card's DAC Lookup Table (LUT). This table defines the mapping between what your OS has output after color management and the inputs required to your monitor — your gamma response curve.
The Monaco EZcolor 2.6 + Optix XR package is an excellent tool for monitor calibration and complete system profiling (monitor, scanner and printer). The results have been excellent in producing a screen-to-print and even a print-to-scanner-to-screen-to-print matching workflow. While the printer profiling workflow was quite dependent upon the quality of the scanner, the monitor calibration and profiling process was accurate and foolproof. The quality of the printer profiles may not be perfect because of the round-about way of indirect measurement, but they have been extremely good in my own experience. Finding a better printer profiling solution will likely involve consider expense and additional hardware (spectrophotometer).
What I didn't like about the system was that it hid too many details from me that were necessary for me to assess the quality of the resulting calibraiton and profiles. For example, I would like to see the L*a*b or delta-E results after profiling. There are ways that I can dig out the data, but this is a hassle. However, it's clear that Monaco has chosen to provide this information only in their higher-end Optix XR Pro solution (upgrade price is U$149, full U$199), not the entry-level Optix XR.
Overall, I would have to highly recommend this combined package for a serious hobbyist digital photographer seeking a color-managed workflow.