It is a must to say that for getting a right visualization of our images or photos it is essential having our monitor calibrated. If we upload our photos to a photographic forum, to a blog, to a web page, we can be sure that everybody will see our images correctly. When we talk about printing or taking our photos to the lab, this is a totally different issue, because here have influence, and a lot, the printing device profiles and its properly configuration. But it is absolutely clear that to configure a correct printing profile it is a must to calibrate our monitor first and it is a lost battle if we do not do this in that way.
There is a lot of software programs, some free, that make " by eye" calibrations as Adobe Gamma, Monitor Calibration Wizard or Quick Gamma, this last based in the level charts and black from Norma Koren, but all of them has the subjective and estimative disadvantage and they are very affected by luminic ambient conditions from our room, because it really influences if you calibrate by day or night, blinds or curtains open or closed, it can affect our monitor if we do it with white or light color clothes, maybe this reflects some light to monitor and can lie with the adjustments we are going to do.
If our monitor is properly adjusted in black and white luminance, we should distinguish every grey block in this graphic:
In color calibration there is in play more variables as RGB channels, Gamma level, Environment light, monitor type and its specifications.. There are so many variables that it is almost impossible to do a right calibration "by eye".
For this tutorial we have used the Spyder 2 Pro system from Colorvision, which is the most advanced version over the very affordable Spyder 2 Express. The process is equally valid for two versions, only that in Spyder 2 Express you cannot make use of the light environmental compensation neither can measure luminance, it only uses estimated luminance. The measured luminance is absolutely necessary to calibrate exactly several monitors located in the same room. But Spyder 2 Express makes its work gorgeously and it is a perfect tool for the photo edition work.
Before start, we should disable the Adobe Gamma from system so that Windows or Mac can load the ICC profile created by Colorvision and be this one that is always loaded by defect. In Windows we must do it with an administrator account.
We must know that LCD and CRT monitors should be working at least one hour and projectors about ten minutes before calibration. Remember we should disable the monitor energy saving options, because if it fades, you need to repeat the whole process from the beginning.
The software will request us information on the screen type, LCD or CRT, and we leave activated the grey balanced calibration option
Now select the values that we want to apply to monitor calibration, being the most common the 2.2-6500 option for monitors, in this case with a black luminance of 0,67 and a white luminance of 0,85 candles m2 (cd/m^2) since in this case the room light levels are in particular very low and room light values as zero, total darkness, are not recommended.
Colorvision classifies ambient light in 5 levels:
- Very Low
- Low
- Moderate
- High
- Very High
In the Very low level, LCD and CRT monitors can be used indistinctly with values of 85-100 cd/m^2 and a 5000K white point. In the Low level, both monitor types can be used equally with values of 125-150 cd/m^2 and a 5.800K white point. With Moderated level LCD monitors can be used, because CRT is no longer too reliable.
In the following steps the software ask to us to place the colorimeter in the monitor
And now the calibration process really begins.
After the sensor first measure, we will raise the contrast without blow out the whites until we can just distinguish the white blocks
Then adjust brightness until the lowest value we can distinguish the black blocks
Then, when the main things are adjusted and have an acceptable value, the RGB channels adjustment begins, showing and checking a patterns series in the primary RGB channels and it finishes with the analysis and adjustment of color temperature with three variables: black, grey and white. At the end the software creates an ICC profile that will be saved in our system and later loaded as standard monitor profile
The final check chart presented at the process end compares between the corrected and uncorrected image, observing the improvements quickly:
The conclusion is very easy, the Spyder 2 is a highly recommended product due to its excellent quality / price factor, and with and affordable cost, the Spyder 2 Express version is almost an obligation to have it at home as necessary tool in our photographic system.
© 2008 Juan Parménides. Derechos Reservados. All Rights Reserved