Why do we need monitor color calibration ?
The Ugly Truth – The painful way of learning why and how to calibrate monitor
I want you to consider the following scenario. At some point you buy a new PC, Mac, whatever, and it has a nice big screen. So you install all of the programs you use, choose a nice desktop background, and tweak the monitor settings, such as brightness, contrast so that the desktop looks pleasing to the eye.
Still with me ? Good.
At a certain point in time, you buy your first camera, and catch the photo bug, and start shooting, and after learning camera and composition basics, your photos start to look really good. You receive recognition from friends and family. Encouraged, you start editing your photos to look even better in tools such as Adobe Photoshop, Lightroom, or Paint Shop Pro.
You build a nice image collection and get good feedback from photography forums and sites like flickr, smugmug, and decide it’s time to take next step and start printing your photos. So you invest in solid printer for printing photos, and start printing. That is when the problems start. No matter what you do, the colors in the printed photos just look way off when compared to the same photo on your monitor.
What went wrong ? Well, a lot…
Time to learn about color management….
What is color management ?
“Color management” is a process where the color characteristics of every device in the imaging chain is known precisely and utilized to better control color reproduction. It often occurs behind the scenes and doesn’t require any intervention, but when you start to have color problems, understanding this process can be critical.
In digital photography, this imaging chain starts with the camera taking the photo, and finishes with the final print, and may include a display device in between.
Coming back to our scenario, let us examine what exactly went wrong in the diagram below:
As you can see from the diagram, there are approximately 7 factors that impact IF the colors displayed on the monitor and printed photo will be true to original taken by the camera:
- When camera takes photo the most accurate colors are preserved if the photo is saved in camera RAW. Camera, when converting the image to JPEG applies a color profile and compression, which results in a loss of some of the original color information recorded in the RAW.
- The image is stored as a file on a hard drive, and when viewed the display device (graphics card) interprets the colors based on the information in the graphics driver. Note that every manufacturer interprets the color tones similarly, but slightly different, which is enough to cause some color inconsistencies.
- Assuming the monitor is not calibrated, there are numerous controls on monitor that can impact the colors displayed on the device such as: brightness, contrast, color temperature, and default color profile. Note that monitor’s color profile is device specific and does not need to concur with camera’s color profile.
- To further complicate the matter, regardless of how the monitor is set up, the ambient light under which we observe the image also plays a significant role on how we perceive color. The stronger intensity of light hitting the monitor, the less colors we will see. That is why the photos should be developed in a dark room (where the monitor is the brightest light source), otherwise our eyes will adopt to the ambient light, disregarding the colors in the monitor.
Now I want you to consider one important thing. Factors 2,3, and 4 affect ONLY the display of the photo, and not the actual file. So, when we edit the photo in e.g. Photoshop, we trust our eyes, and our monitor that the colors we see are accurate. The scary part of the story is that we are modifying the actual file stored on our computer based on the colors presented to us by a potentially uncalibrated display. In short, if colors in the display are way off, we are actually destroying our images.
- When trying to print the photo on a printer, a printer driver will assign the photo a default color profile for the printer (unless stated otherwise), that usually has nothing to do whatsoever with the color profiles of the camera or the monitor. The printer colors need to be converted from the RGB color space (used to display colors in monitors), to CMYK color space (used by the printer), and during that the colors of the actual image file on the disk (not the image shown on screen) are being used as a base for conversion.
- Color profile that will be used for printing should match the printer device and inks being used, as well as the brand and type of the paper. That is why printer manufacturers always recommend to use the same paper brand as the printer, to ensure most accurate colors.
- Finally, the printed image is not immune to the ambient light either. There is a slight difference in perception though between photo as on monitor and printed one. Monitor IS a light source, while printed photo merely reflects ambient light, and therefore the colors we see might be perceived differently.
So, the question is: How to get the colors to be consistent across the board ?
By trying to match camera, monitor and printer color profiles to a “standardized” one. For a monitor, we call that process monitor color calibration, and for printer we call it printer profiling. We will focus around monitor color calibration as we believe it is the most important component, and the most costly one if it is wrong.
Remember, you are editing your photos based on your monitor’s output, so don’t you think that the difference between what you see on your monitor, and the actual image file is absolutely essential to be minimal ? We certainly think so.
How to calibrate monitor ?
First I want to make one thing clear: calibrating your monitor does not guarantee you full print-to-screen color accuracy, although it improves your chances. It also improves the chances that if you send your photos to a professional print studio, the colors in your photos will be accurate.
1. Manual Color Calibration
Pros: Easy, Fast, Cheap;
Cons: Not as accurate, subject to exterior light
For those of you that want to try to calibrate your monitor manually, Smoking Strobes has posted an excellent and easy guide on how to calibrate monitor, which includes a color calibration diagram. It’s quick and easy.
It involves tweaking your brightness and contrast settings, until all of the numbers in the provided image can bee seen.
While this simple monitor color calibration technique will not have the accuracy of the dedicated hardware color calibration tool, or the monitor calibration software, it will go a long way in improving the accuracy of the colors you see on your monitor. Author claims that by manually tweaking your brightness and contrast it is possible to reach up to 95% of the screen quality. Note however that this color calibration technique will not help remove color casts that might be present in your monitor/graphics settings.
2. Dedicated Hardware Color Calibration Tool
Pros: Easy, Step-By-Step, Accurate;
Cons: Not so cheap, requires hardware
Common calibration devices (sensors) include the X-Rite Eye-One Display, ColorVision Spyder, ColorEyes Display and ColorMunki Photo, amongst others. Each of them comes with their own monitor calibration software and instructions. Personally, I use ColorVision Spyder 3 Pro. The color calibration process is simple:
Before beginning, make sure that the following conditions are met:
a. Make sure that your monitor is warmed up (turned on for at least 30 mins)
b. Make sure that there are no strong light sources hitting the monitor
c. Reset monitor to factory settings, and make sure color temperature is set to 6500K
… then, put the sensor in front of the monitor, follow the step by step guide of your monitor calibration software, and let it work its magic. Images below describe the calibration process.
The benefit of using a dedicated hardware color calibration device is that it does most of the heavy lifting, by evaluating the colors as they appear on the screen, it effectively takes both graphics card and monitor out of the equation as potential sources of color inconsistency. That way it ensures that the colors you see on your monitor are accurate.
I like the fact that ColorVision has added to Spyder 3 Pro a light sensor, which could detect ambient light in the room, and given the fact that it’s constantly connected to a PC while sitting in it’s cradle, it can give you a head’s up if you need to re-calibrate your monitor due to change in your environment.
Let us know what are your experiences with color profiles and monitor color calibration. What is your preferred monitor calibration software, and do the colors in your prints match accurately to your images on your computer ?