THE MYTH OF THE SCREEN-TO-PRINT "MATCH"
28th February 2011
One of the biggest misconceptions in colour management is the belief that you calibrate your monitor and printer to match each other. If you think that’s how it works, you’re not alone. And that belief will cause you problems and frustration at one point or another, if it hasn’t already.
Want to break through the misconception and learn how it really works? It’s not hard, it just requires a little under the hood knowledge of colour management.
Let’s start with an example from music. Consider this: If a guitarist and a cellist were playing the same piece of music, would you expect the guitar to sound like the cello? No. We all know that the character of instruments is different, even if they are playing the same notes, so we don’t expect them to be the same. This is also how we should think (though, to a lesser degree) about monitors and prints. The problem with the idea of making your monitor and printer “match” is that it forgets about the file itself…and the fact that the file is the most accurate representation of colour.
Files, by their nature, are what contain the colours we want to reproduce. They are the most accurate representation, even though they record colour in a numeric form our eyes can’t see. To see the colours, we need output devices, monitors and printers, which convert those numbers into a visual representation. To understand how they work together, we need to understand how colours are stored and translated.
Files contain the formula to actual colours, not just a vague definition of a color. A pixel value of 211R 0G 0B doesn’t just mean the 231st step of red above zero. It means a very specific colour, as plotted in the spectrum as defined by a specific ICC profile.
The problem with monitors and printers is that they are each limited in the colours they can reproduce. This is constrained by things like gamuts (the range of colours they can create) and white points. When we measure and define the colours a device can produce, we have its colourspace, which can be described in a ICC profile.
The file almost always has more colours than the devices we use to display colour. The way colour management works is it uses these ICC profiles which describe a device’s colourspace to map the colors from the file’s colourspace into the device’s colourspace as accurately as possible.
Why? Well, you can’t just feed a pixel value of 211R 0G 0B from the file into a printer or monitor and expect to get the right colour red. In all likelihood, you’ll need to feed in an entirely different combination of RGB values to the output device in order to get the same exact colour as defined by 211R 0G 0B in the file. The colour profile contains the information that lets the computer translate colour from one colourspace to another.
This is the important point. Colour management IS NOT trying to make the monitor match the printer. Instead, it’s trying to make each device, independently of any other device, represent the file as accurately as it can, within its own limitations. The file is always the starting point; monitors and printers are just representations of the file.
The reason we see a “match” between profiled monitors and printers is this: When we make each device represent colour as accurately as possible, if the two devices are similar enough, then those two devices often display the colour in a similar manner…so similar that we can say we have a “match.”
This is what leads to the idea of the “match,” and that idea causes many photographers great frustration. When one of the devices is more accurate than the other (usually the print, because a good print is more accurate than any monitor), then the photographer sees a difference between the two, and no longer thinks they are “matching.” The usual response is to think something has gone wrong, because they are expecting a match.
Instead, the photographer should understand what colour management does, and conclude that they are seeing the limitations of the device. You have to realize that devices like monitors do not represent the print 100% of the time so you can shatter the myth of the match.
Now, I’m not recommending you throw away your colour-accurate monitor, but to understand and work with its limitations. A true colour-accurate monitor that has been accurately profiled can produce an extremely good “match” to a print for a wide variety of photographic applications. But when it doesn’t, we should look at the print (printed with a proven ICC profile) as the most accurate representation. One would not expect a student violin to sound like a Stradivarius, would they? So, while our monitor may be good for many performances, we’ll need to pull out the Stradivarius (the print) for our most breathtaking music.
Colour Management is called “management” not “matching” for a reason, and now you know why!
Want to break through the misconception and learn how it really works? It’s not hard, it just requires a little under the hood knowledge of colour management.
Let’s start with an example from music. Consider this: If a guitarist and a cellist were playing the same piece of music, would you expect the guitar to sound like the cello? No. We all know that the character of instruments is different, even if they are playing the same notes, so we don’t expect them to be the same. This is also how we should think (though, to a lesser degree) about monitors and prints. The problem with the idea of making your monitor and printer “match” is that it forgets about the file itself…and the fact that the file is the most accurate representation of colour.
Files, by their nature, are what contain the colours we want to reproduce. They are the most accurate representation, even though they record colour in a numeric form our eyes can’t see. To see the colours, we need output devices, monitors and printers, which convert those numbers into a visual representation. To understand how they work together, we need to understand how colours are stored and translated.
Files contain the formula to actual colours, not just a vague definition of a color. A pixel value of 211R 0G 0B doesn’t just mean the 231st step of red above zero. It means a very specific colour, as plotted in the spectrum as defined by a specific ICC profile.
The problem with monitors and printers is that they are each limited in the colours they can reproduce. This is constrained by things like gamuts (the range of colours they can create) and white points. When we measure and define the colours a device can produce, we have its colourspace, which can be described in a ICC profile.
The file almost always has more colours than the devices we use to display colour. The way colour management works is it uses these ICC profiles which describe a device’s colourspace to map the colors from the file’s colourspace into the device’s colourspace as accurately as possible.
Why? Well, you can’t just feed a pixel value of 211R 0G 0B from the file into a printer or monitor and expect to get the right colour red. In all likelihood, you’ll need to feed in an entirely different combination of RGB values to the output device in order to get the same exact colour as defined by 211R 0G 0B in the file. The colour profile contains the information that lets the computer translate colour from one colourspace to another.
This is the important point. Colour management IS NOT trying to make the monitor match the printer. Instead, it’s trying to make each device, independently of any other device, represent the file as accurately as it can, within its own limitations. The file is always the starting point; monitors and printers are just representations of the file.
The reason we see a “match” between profiled monitors and printers is this: When we make each device represent colour as accurately as possible, if the two devices are similar enough, then those two devices often display the colour in a similar manner…so similar that we can say we have a “match.”
This is what leads to the idea of the “match,” and that idea causes many photographers great frustration. When one of the devices is more accurate than the other (usually the print, because a good print is more accurate than any monitor), then the photographer sees a difference between the two, and no longer thinks they are “matching.” The usual response is to think something has gone wrong, because they are expecting a match.
Instead, the photographer should understand what colour management does, and conclude that they are seeing the limitations of the device. You have to realize that devices like monitors do not represent the print 100% of the time so you can shatter the myth of the match.
Now, I’m not recommending you throw away your colour-accurate monitor, but to understand and work with its limitations. A true colour-accurate monitor that has been accurately profiled can produce an extremely good “match” to a print for a wide variety of photographic applications. But when it doesn’t, we should look at the print (printed with a proven ICC profile) as the most accurate representation. One would not expect a student violin to sound like a Stradivarius, would they? So, while our monitor may be good for many performances, we’ll need to pull out the Stradivarius (the print) for our most breathtaking music.
Colour Management is called “management” not “matching” for a reason, and now you know why!
