Color management

You can print a print file by a print shop in another continent within the borders of our country… but how?

As a designer or print supervisor, have you had the opportunity to be by a printing machine for many hours to get the color you want, or ultimately, leave what you wanted after a lot of trial and error? And have you encountered an amateur designer or supervisor, who requested you as a printing machine or production operator to use more ink by having a file and a plate with 5% Cyan plate, without knowing what the secondary problems will be for you?

How many minutes and hours have you lost to get to the color that only he has in mind? How much paper or cardboard have you trashed? How much have you tried to explain and he has not noticed that production efficiency has dwindled during those hours?

Have you ever experienced how to obtain a repeatable and permanent color by change the substrate, the type and material of the cardboard?

If you’ve been through such problems, you should know that in today’s print world, there is a scientific way to solve them!

The Miracle of science:

We have all heard familiar names like CMYK or RGB many times, and we know that when we talk about RGB we are in fact talking about “light”. Both of these concepts are device-dependent systems. This means that by changing the device, we increase the chances of changing the color output that we see in the end. We should know that by system, we mean the machine, tool and basis.

For example, the RGB tool can have an LCD, and the CMYK base can be cardboard or paper, which means a still image will be seen in two different LCDs or LEDs, or if a completely identical file was printed on two different cardboards (e.g. one on the ordinary cardboard and another on a coated cardboard), or if the same file was produced on one cardboard by two different printing machines, we would likely come in different colors.

In our country, it is possible that different print operators will likely come up two different colors from the same file, or even one operator may deliver a file that was printed a month ago in a different color… This is what “Color Management” does not accept.

Older control systems and control tools have all taken serious steps to solve these problems, but most of them have focused on the ink density control, and, as we are well aware, density, the ink density is a concept that depends on many factors such as the ink brand to the degree of control over the temperature of production in the printing machine and even the environment in which the printing operation takes place. Thus, controlling the ink density was not and is not the only solution to the problem. In addition, the printing industry has been in search of a more profound, ever-evolving solution to print that has always had the essence and type of print basis.
How does color management work!?

The human visual system itself is a very precise and sophisticated device, but in spite of all its complexities, it cannot distinguish all the visible light spectra. Based on the “color contrast theory”, the human eye is able to distinguish the yellow spectrum from blue to green to red, and this human ability is the status, on which the color space L * a * b * is based.

Suppose we put all the colors in the world into one sphere in such a way that the two ranges of green to red (from –a to + a) and yellow to blue (from –b to + b) are included. If we add a lightness axis to these two spectra, we can have all the colors of the world in this sphere. Every color that we see will actually be somewhere in the three axes L (light), a * (green to red) and b * (yellow to blue). Therefore, we can have the numbers of each of the three axes in a three-dimensional address, which we get from that color, and we call it L * a * b *.

Since each unit is unique on each of the mentioned axes, the L * a * b * of each color is just as unique as our fingerprints of the humans. Thus, L * a * b * of a color, in a completely three-dimensional sense and completely independent of the system, addresses the 3D state of that color; no matter it is printed on a cardboard or fabric or glass!

Let us consider some examples:

Suppose we have a color that its L * a * b * is L: 30, A: -15, and B: +17. We put this color next to another color, whose L * a * b * is L: 10, A: – 15, and B: +17. What comes to your mind, when comparing these numbers?

Let us look more precisely:

The numbers a * and b * of these colors are both exactly the same, meaning that the position of both colors on the yellow-blue and green-red spectra are quite similar, with the only difference being their position on the L * spectrum, which is the light spectrum.

The first color with the number 30 coincides with the L * light axis, above the second color with the number 10, simply indicating that it has a lighter color.

How to achieve color management?!

A standard process should be followed to achieve the standard printing, in which all processes are controlled from start to finish, and color management is just one of these steps. In addition, we need to know that to manage the output of a process we first need to control the inputs of that process. Hence, we control the output of the print file to control the output of the printing process.

One of the best, yet the toughest standards in the world in this area is the German standard FOGRA, which in its Fogra39 version provides several specifications for controlling the entry and exit of the “offset sheet fed” printing process that can be achieved with color management.

In addition, the accredited standard organization (ISO), also explains L * a * b * by using the FOGRA39 featureISO 12647-2 standard, ISO’s accredited organization explains the use of FOGRA39 features to achieve color management processes in its ISO 12647-2 standard.

Obviously, a standard output first needs a standard input. For example, the color system on which the file is designed must also be acceptable by the printing machine, which is the “web coated” system in Fogra39 standard.

There is a famous term in management that indicates: “To manage a concept, you must first measure it”.

We should also be able to measure the distance between L * a * b * of two colors. This distance is called “ΔE”. If the ΔE is less than 0.5, the eye cannot detect it, and if it is between 0.5 and 1.0, it can be difficult to detect. CMYK prints should have ΔE of less than 5, and that in “spot” color prints should be less than 2.

It is a simple job: a standard file will lead to a standard print. You just have to have the right file. In addition, with the knowledge of color management knowledge, you no longer have to worry about achieving results when printing. By standardizing your file, you can be ensured about the results. For instance, in the field of “packaging”, you only need to meet the standards set by manufacturer implemented FOGRA39 and ISO 12647-2 in order to deliver your file and request proofing.

You can see what is finally to be printed before even your plate is made and ensure the correct operation.

If you are not familiar with its features, an organization that has implemented color management can well guide you in standardizing the print file.

Mehdi Shabanipour
Marketing and Sales Manager
Teram Industrial Group

Read the rest of this article in the Ergotronic article.