WHY DON’T MY PRINTS MATCH MY MONITOR?
A Color Management Primer
by Louie Aguinaldo

In recent years, more and more photographic dark rooms have moved inside computers. In many photo labs, even printing from negatives consists of scanning and viewing through a monitor before printing. Whether the photograph had been taken with a traditional film camera or a digital one, editing the image on the computer is becoming the norm.

One immense advantage with the digital darkroom is that it allows the photographer to have practically full and precise control over the colors and tones of his photograph. With today's almost miraculous photo editing software, we magically change colors within seconds. Unfortunately, this miracle often meets a stumbling block. After being pleased with what we see on the computer, we then send our masterpiece to be printed and are disappointed with the outcome! “Why don't my prints match what I see on my monitor?” There is a solution to this – Color Management.

*This article was written mainly to serve clients of DPI Photography Center . Since DPI photography center uses RGB printers, the portions with regards to printing are geared more for RGB printing done at photo labs such as DPI's professional photo lab. Not much information regarding CMYK printing is dealt with here but, much of the basics of color management is included.

Factors:

To solve this problem, we first have to be aware of a number of factors.

1) Monitors and Prints are different – What we see on a monitor is emitted light. What we see on a print is reflected light. Due to this difference, we can't get an actual 100% accurate match. The nature of both types of light and how our eyes react to them makes color consistency between them a bit of a challenge. Even LCD monitors are different from CRT monitors – the inherent brightness and contrast differ greatly. Still we can control the conditions to achieve a relatively accurate match.

2) Each Monitor is Different – Observe an appliance store with so many television sets on at the same time, they show the same programs, yet each TV shows varying colors and hues? Computer monitors are like that, though they may be made by the same manufacturer, each monitor has its own unique characteristics. Even monitors of the exact same model can display colors differently especially since each user can adjust colors, brightness, and contrast to suit their own liking. Thus, you may be in for a surprise when you view your color-adjusted masterpiece on another computer and find it all of a sudden too reddish or greenish or even too bright. The fact is that what I see on my monitor is most likely not going to look exactly the same on another monitor.

3) Printers are Different – Printers produce colors differently from monitors. Also, each printer produces colors differently from other printers. Monitors can display more colors than a printer can. The colors you see on a monitor are a combination of 3 beams of light (RGB) red, green, and blue. Most printers produce colors from at least 4 inks (CMYK) cyan, magenta, yellow and black. Desktop printers are examples of CMYK printers. Some printers, like those in photo labs, are RGB printers. They don't use inks but use RGB beams of light to produce the printed photograph. Even if they are similar to monitors in the sense that both use RGB beams of light to produce color, these RGB printers will still produce colors differently. Try sending an image to two different printers and you will notice that there will be visible differences.

4) Photo Papers are different – We already mentioned earlier that prints show reflected light while monitors show emitted light thus, there is a difference in how they will render color and tone. Aside from this, different types of paper will affect the way colors will appear on them. Just check out a store selling different brands of bond paper. You will notice that though they are all white, some are slightly bluish, some are slightly warmer, etc. Photo papers also come in different variants, glossy, matte, silk (semi-matte), and even metallic. The different types of paper, in combination with different printers, and processes will surely result in prints with different results. Some might have more contrast; some colors might be stronger or weaker.

5) Each digital device speaks a different dialect – All your digital devices speak the same language -color. Still, the language of color comes in different dialects. Some dialects more different than others – RGB, for example, varies largely from CMYK. Scanners, monitors, digital cameras, printers and even imaging software speak a different dialect of color from each other. In differing dialects, a similar word may have a slightly different meaning. Likewise, the pure red of one device may not be the same red of another device. The dialects come in the form of color profiles and color spaces. If you dabble in Adobe Photoshop you will come across ‘color spaces' or ‘color profiles' termed sRGB or Adobe RGB and the like. This may sound complicated but this is an essential reason why different devices produce colors differently from each other. In a sense, this sums up a lot of what we have discussed earlier.

6) Ambient light makes a difference – The light you use to view your photographs affects the way the color appears. Light comes in varying color temperatures. Incandescent light, for example, has a low color temperature and appears very warm (yellow, orange, red). Sunlight on a cloudy day has a higher color temperature and appears cooler (bluish). The monitor you use to view your photos with is set at a specific color temperature. Now, if the color temperature of your monitor and your viewing light differ, then chances are there will be noticeable visible color shifts between your printed image and what you see on the computer screen.

7) Ambient colors can affect how we see our images – Light has a tendency to bounce off walls and other surfaces. When it does, it reflects the color of the surface it just bounced off from. If the walls in your room are bright red, then chances are you will have a red cast thrown about the room. If you are working on the computer and are wearing a bright yellow shirt, chances are some of the yellow will bounce on to the monitor's glass screen.

8) Out of Gamut – Color gamut is the range of colors that a device is capable of producing. Each device or medium has limitations with regards to the range of colors it can produce. Some color spaces have a wider gamut than others. Adobe RGB, for example, has a wider gamut than sRGB. This means that in Adobe RGB, more colors are possible than in sRGB. Monitors have a wider gamut than prints. Monitors, being emitted light, can produce more colors than prints which are limited by qualities of paper and inks. Still, there maybe some ranges of color that may be capable of being printed but cannot be produced in monitors. This being the case, there will be some colors that we view on a monitor that are not physically possible to be produced in prints. Though Color Management Systems offers solutions to this through different rendering intents (we will touch on this later on in this article), which produce substitute colors, the colors are not exactly the same. So, we must tem per our expectations by being aware of this limitation. Not all colors we see can be exactly reproduced.

Solutions:

Color Management is a system wherein different devices are made to communicate color accurately and efficiently with each other. As mentioned earlier, different digital devices speak a different dialect. Through a color management system, a sort of interpretation process occurs such that each device understands what the other device wants to say. The bulk of the solution to solving the problem of monitor-to-print matching lies with color managing your system. Second to this would be optimizing your editing and viewing environment.

1. Calibrate and Profile your monitor – As mentioned earlier, monitors differ from one another. Through calibration, one adjusts the monitor to a universal standard. Profiling is another procedure wherein a file is created that describes how a particular monitor renders color. The profiling process creates a monitor profile which is also known as an ICC or ICM profile. This file is a sort of dictionary that defines the ‘dialect' your monitor speaks.

Calibration and profiling can be done through software such as Adobe Gamma (which is installed with Adobe Photoshop), or Colorsync in the Macintosh systems. These software allow you to calibrate your monitor visually and can do a pretty good job. For greater accuracy, one can purchase devices such as colorimeters or spectrophotometers which are capable of precision calibration and profiling together with their accompanying software. Unfortunately, these devices with their software can cost anywhere from the hundreds to the thousands of dollars.

Calibration and profiling through Adobe Gamma is quite simple. Just start it and it will take you through the process step by step. Within a few minutes you have a calibrated and profiled monitor. Though its accuracy is largely dependent on your vision, it is much much better than nothing.

2. Obtain a printer profile – Just as monitors have a profile which describes the way it renders colors, printers also need a profile to do the same. In fact, a printer needs an ICC profile for each type of paper. The exact same printer will most likely render different colors, contrast and brightness when it uses different paper types. Glossy paper, for example, usually comes out with more contrast than matte papers. Once a printer profile is available, a color management system allows an accurate conversation between your image file and the printer you will print it with. So when your file intends a particular red, your calibrated and profiled monitor will display that red accurately, and your printer will print that red (or at least as close to that red as possible.)

Printer profiles are usually made available by the printer manufacturers. Unfortunately, these profiles are generic and may not be very accurate. Again, this is better than none. Digital labs should have printer profiles available, ask them and they should make them available to you. Professional labs most likely have custom profiles made. Custom printer profiles should be the most accurate printer profiles available as they have been made for a specific printer unit.

One can also create custom printer profiles through software and hardware but these are quite expensive. There are some companies abroad that can make custom profiles which is a cheaper alternative than purchasing the hardware and software.

Of course, if you send your prints to the lab, make sure that your lab is color managed and has custom printer profiles available for each of its paper types. Otherwise, there will be a less likely chance that your prints will match what you expected.

3. Preview your images using the Printer Profiles – Adobe Photoshop allows you to view your images as to how they would appear when printed using a particular printer. This procedure is known as soft proofing.

First of all, make sure that you have a profile for your printer. These files end with either “.icc” or “.icm”. If you are using windows, just right click and select install. If you are using the Mac, you have to copy the profiles into library\colorsync\profiles .

•  open an image in Adobe photoshop

•  select VIEW / PROOF SET UP / CUSTOM – a little box will appear

•  select the drop down menu next to Profile

•  select the profile of the printer/paper you will be using (example DPI Glossy)

•  leave Preserve Color Numbers unchecked

•  for Intent select Perpetual (for most photo purposes)*

•  check Use Black Point Compensation

•  if you want to see the white of your monitor match the white of the paper, check Paper White – this may appear to make the image lose contrast – to overcome this, look away when you check this. We see a drastic dulling appearance because we witness the shift from the brilliance of the monitor to paper white. So, if you don't watch the shift, it will not appear as dull.

* There are four options for Intent – Perceptual, Saturation, Relative Colorimetric, and Absolute Colorimetric. They represent different methods of how the color management system will reproduce out of gamut colors (colors that can't be reproduced by a device). If you are printing yourself through your desktop printer, you have the option for experimenting your rendering intents. For most photographic purposes, Perceptual is recommended.

Soft proofing becomes a critical tool if color matters to us. We are enabled to see ahead of time how the colors of our image will appear when printed. We will be able to see the shifts of color and make adjustments if necessary. Remember, printers cannot produce the same wide range of colors a monitor is capable of displaying.

4. Optimizing your viewing light – As mentioned earlier, the light we use to view our images is very important. Not only does the color temperature of the light affect the colors we see, but even the intensity of the light affects how bright or dark the image will appear when compared to the monitor. In high-quality printing presses, a viewing booth with a 5000 degree Kelvin light is used for viewing their prints with their monitor calibrated to the same setting. Unfortunately, such viewing booths and the bulbs used for them are very expensive and not practical for most users.

Improvising with what is available and affordable would be the most practical option. First, select only one light source. Some places might have a mix of light sources; incandescent and fluorescent lights on at the same time. Only one light should be used. Ideally, filtered sunlight through a window would be best. Unfortunately, the intensity and color temperature of sunlight cannot be controlled. The time of day, the amount of clouds that pass by, will constantly cause shifts in your viewing light.

One seemingly logical solution is to buy daylight bulbs with a color temperature of 6500 degree Kelvin ( the same white point we usually calibrate our monitors to ). These daylight bulbs are inexpensive and easy to find especially in the form of fluorescent-like energy saving bulbs. Unfortunately, though they may have the color temperature of daylight, there is a flaw to them that interferes in our viewing of prints. The ideal type of light is sunlight. The reason being is that the colors in the spectrum of light are even in sunlight. With artificial light sources, this is not the case. These energy saving daylight bulbs have an imbalance of colors: the green spectrum is much stronger while the reddish spectrum is a bit subdued. Thus if you compare your print viewed under such light to your monitor calibrated at 6500 degree Kelvin you will probably notice that skin tone on your monitor appears more reddish while it will be slightly greenish on your print.

You may wonder if there are bulbs that are closer to the even light of the sun. Yes, there are. Bulbs actually have another rating – CRI – Color Rendering Index. This rating refers to how close the bulb is to the even spectrum of sunlight. The higher the rating the better. For viewing prints, a CRI of 90 or higher is preferred. Only sunlight has a CRI of 100.

Unfortunately, the CRI rating usually appears only in expensive high end bulbs which are not readily available locally. Most of the light bulbs available have low CRI ratings such that manufacturers don't even bother to indicate it. Daylight energy saving bulbs have a CRI rating of between 60-70 only, quite far from sunlight. So unless you can afford to create an accurate viewing booth, you would have to settle with improvising.

One way to improve this situation is to take into consideration your ambient light when calibrating your monitor. When you calibrate via adobe gamma, you have that option. Unfortunately, since everything is done visually it is not the most accurate method, but it is better than none. Some higher end calibration hardware have a feature wherein you can actually measure your viewing light off a white sheet of paper. You can then enter the values you measured and calibrate your monitor to that color temperature. This should give you better match between your monitor and print since the color temperature of both your ambient light and your monitor's white point are the same.

Another important point that needs to be considered is the intensity of the viewing light. Some people complain that the prints they have are darker than what appears on their calibrated monitor. In such cases, the most obvious culprit is that the ambient light is too dark. Your viewing light should be bright enough to match your monitor. Take a white sheet of paper and compare it to a white image in adobe photoshop, adjust your light so that the brightness matches.

5. Create a controlled working environment – Since light tends to carry the color of an object it bounces off, colored walls or curtains can definitely affect your viewing. For best results, have an environment that contains neutral tones such as white or gray. For critical editing, some suggest neutral clothing as well. Bright colored shirts can bounce light onto your monitor also affecting the colors you see.

Many graphic professionals make use of a monitor hood to prevent ambient light from directly hitting the monitor. Ambient light can produce some amounts of glare and reduce the contrast we see on the monitor. A simple hood can be fashioned out of black illustration boards.