▷ How to calibrate monitor 【step by step】 【best methods】

Some time ago we have been incorporating in our reviews a section to calibrate the monitor for the analyzed models. In fact, as a result of this article we have chosen to work with DisplayCAL, a free solution with which we will see a lot of information about our monitor and we will be able to calibrate it almost automatically.

We will carry out this process with the Asus PA32UCX, and we will see how its features and color are improved thanks to this simple tutorial. We can do this practically with any monitor that we connect to our PC, even with printers, projectors, or scanners for the most demanding.

What is the use of calibrating a monitor or other device?

Calibrating a monitor is something that is practically mandatory if we are professionally dedicating ourselves to photography or content creation. We know that a monitor is capable of representing images digitally thanks to an RGB pixel matrix provided with a backlight that is responsible for giving the necessary brightness. Well, most monitors do not represent what colors are like in reality, at least it will not be like this until they are calibrated.

Precisely calibrating the monitor will help us so that, through a device that basically photographs our screen while a series of colors pass through it, it manages to represent the colors as our eyes would see them in reality. In this way, an image that we create on our PC with a calibrated monitor will get as close as possible to reality. And the same happens if we make a video, if we scan a document or if we project a video clip. All these elements are capable of being calibrated.

Many times, we compare the quality of the images that a Smartphone captures by the degree of similarity that these have with what we see in reality. Exactly the same thing happens here, each monitor represents colors in one way, and maybe the red color you see on your monitor is a pink or orange color in another. This is the goal of a calibration, and on a monitor intended for design, it is practically mandatory.

A calibrated monitor shows the true color of the photos and videos represented on it, not the colors that come with it by default.

What I need

To calibrate the monitor we basically need two things, a colorimeter, and calibration software.

A colorimeter

First of all, we will have no choice but to buy a colorimeter. A colorimeter is a device equipped with a photographic lens that is capable of identifying color and its nuances. Photograph the screen while showing a certain color palette to buy them internally with reference colors considered real. In this way it is possible to correct those nuances on our monitor and modify the color that is represented on it. There are quite a few colorimeters on the market, and obviously there are low, medium and high range. These will be its main differences and similarities:

• For starters, none is really cheap, and a decent one can cost us between 150 and 250 euros, at least one that is of sufficient quality. Of course, all of them are capable of calibrating a monitor without problems, even with a very similar quality. The difference between the different ranges is that the higher cost ones are capable of calibrating in addition to monitors, projectors, printers, etc. An important detail is that they are also faster, for example, the X-Rite ColorMunki Display is much slower to calibrate than the X-Rite i1DisplaPro. The more expensive, the higher the accuracy, this is almost evident. Higher-cost devices are able to more accurately distinguish color nuances, especially if they are Pantone and style certified. The software behind them is a big difference. The cheapest equipment has very basic and almost automatic calibration programs, while the most expensive have programs with many more options. That is why we will use a free and free one, the DisplayCAL 3.

Interesting colorimeters can be the ColorMunki Display (which we use) or the X-Rite i1 DisplayPro, or the Datacolor SpyderX Pro or Spyder5 Pro. If we are looking for something even more professional we can choose the X -Rite i1Studio.

X-Rite CMUNSML ColorMunki Smile - Monitor Calibrator (Software Included), Black For calibrating LCD and LED displays - laptop or desktop; Easy and intuitive interface X-Rite ColorMunki Display - Screen Calibrator for monitors, projectors and tablets, Black Color Screen alignment function Datacolor Spyder5PRO - Screen Calibrator, Black Ensures the calibration of all your laptops and desktop monitors; The software guides you in 4 easy steps for exceptional color accuracy EUR 280.88 Datacolor Spyder EUR 129.00 X-rite i1Display Pro - Monitor and monitor calibrator and profiler Ergonomically and technologically advanced multifunctional measuring device; Infinite control of white point, luminance, contrast ratio, gamma and more 223.95 EUR X-Rite i1Display Pro USB QWERTY English Black Keyboard It is compact and easy to carry in its own case; An optimized user experience in the surprising new i1studio software 418.57 EUR

Calibration software

The second element will be easier to acquire, since they usually come free with the colorimeter that we buy, sometimes they even bring physical color palettes to calibrate printers and other devices.

The software behind the calibrator is responsible for supplying the reference color palette, digitizing the data, and providing the corrections it deems necessary to improve the accuracy of the colorimeter. And of course, they create the ICC color profile that will then be installed in our system to leave the monitor calibrated.

The programs available in colorimeters are not usually too advanced, moreover, some even create the profile in a very opaque way and without showing us Delta E results or CIE diagrams of the color spaces. For this reason we will use a free and also very powerful one.

Why use DisplayCAL

We have chosen this program because it is completely free (although the creator will appreciate a possible financial contribution) that will allow us to do practically everything that a payment software like CaIMAN would be able to offer us. At least when it comes to calibrating your monitor.

In addition, it has a fairly intuitive, clean and very easy to use interface even for amateurs or people who are facing this practice for the first time. With it, we can do things like the following:

• For starters, it supports practically any colorimeter, since it works with the Argyll CMS libraries that are also open source. For example, the X-Rite or Datacolor teams will have no problem. It is capable of creating ICC profiles and even 3D LUT curves to work with them. It allows you to calibrate the colorimeter itself and add matrix color correction files or calibration files to spectrometers. We can verify the color profiles created, for example: Delta E, Gamma, White point, luminance, etc. Make very detailed reports of verification of color spaces comparing the parameters considered ideal. Your website has a detailed guide of use, although in English

Important concepts that we should know

We will try to quickly explain the essential concepts that a user who is going to calibrate his monitor must know.

• Brightness: Uniformity: Contrast Ratio: Color Temperature or White Point: Color Depth: Color Space: Delta E: Gamma: ICC Profile: LUT Curve:

The brightness is the luminosity or luminance that an image panel is capable of giving us. In turn, luminance is the luminous flux that is capable of generating or reaching an element. It is measured in cd / m ² (candelas per square meter), although many times we use the denomination nits for its values.

The uniformity of a panel is the difference in luminance that exists between the different areas measured on it. We can divide into how many cells we create an image panel and capture its luminance. In this way we will obtain the independent values ​​in each region to be able to compare them with the rest. Of course, the closer these values ​​are, the better the uniformity.

Contrast is the difference between the dark hue that a monitor can represent and the brightest hue. That is, it is the ratio of luminance between the deepest black and the lightest white.

Color temperature refers to the light that a black body (a body that absorbs all the light that reaches it) will emit when it is heated to a certain temperature. That is the technical explanation, so this black body, which will actually be black, the hotter it is, the whiter its color will be, and then we will say that this is its color temperature. The color range will go from red to blue, or what is the same, from the longest wavelength to the smallest in the electromagnetic spectrum.

Transferring this to a screen or light bulb, the more color temperature it has, the more bluish the colors will be. The ideal temperature for a calibration will be 6500K or neutral white point. Also, the bluer it is, the more damaging it will be to the human eye, which is related to the backlight of the image panels. That is why they implement blue light filters, to eliminate this and protect our sight. For practical purposes we would see a more orange image.

Color depth will be very important when calibrating your monitor. Refers to the number of bits a monitor uses to represent the color of a pixel on its screen. The pixels are made up of three sub-pixels that represent the three primary colors (Red Green and Blue or RGB), whose combination and tones will generate all the existing colors.

When a monitor has a bit depth “n”, it means that this pixel is capable of representing 2 ⁿ x 2 ⁿ x 2 ⁿ different colors on it. For example, a 10-bit monitor has 1024x1024x1024 = 1, 073, 741, 824 colors.

With this we come to the color space, which is an interpretation system for the colors that will be displayed, or what is the same, the set of colors and their organization in an image or video. For calibration purposes, it is nothing more than a mathematical model that describes the way in which colors are going to be represented, using combinations of numbers.

The letter Δ in mathematics always represents a difference between two values. The E in this case means Empfindung in German, and Difference of Sensation in Spanish. Joining this, the Delta E is the difference of sensations of one color and another, that is, the difference between the color represented by the monitor and the one considered ideal in the color space.

When we see the expression ΔE * we are referring to a CIELAB difference (CIE 1976 L * a * b), a derivative subspace of the CIE 1931 XYZ master space. When the Delta E is less than 3, the difference between colors is not perfectible by the human eye, except in the grays, which are more sensitive. If ΔE = 1 the colors are identical.

The Gamma value or Gamma curve of the monitor will appear prominently in the calibration software. This denomination has its origin in CRT or Cathode Ray Tube monitors. In them, the luminance was proportional to the input voltage raised to a power, which was represented as Gamma or γ. For this reason, the representation graph is exponential.

The gamma value in an ideal behavior of a CRT was between 2.2 and 2.5 and this value is precisely what is used in current monitors to simulate such a response. If we access the OSD menu of the monitor, we will be able to see what the Gamma that is being used will be, having to replicate this value in the calibration program for a better adjustment.

The mid-high range monitors are capable of adjusting their color profile to various Gamma, so we will have to be careful and choose a suitable one to calibrate. In any case, DisplayCAL have an option of "report not calibrated screen" that will approximately detect the Gamma you are using.

We define as color profile or ICC profile the set of data that characterizes a color space. It is called ICC because these profiles or color space are contained in a.ICC or.ICM format file. This is what the program will create after calibrating the monitor, a file with a set of parameters that will associate the colors of the monitor with the ideal calibration values, through its RGB configuration.

These are mathematical functions that generate an output color based on an input to create custom color profiles or color tables for calibration. These curves can be one-dimensional or three-dimensional.

An LUT 1D curve has as input each of the color channels, for example R, G and B. In these columns are all the color inputs, from the darkest to the highest luminance, for example for a monitor with 8 bits we will have 256 values ​​2 ⁸ = 256 in each column.

A 3D LUT curve uses each color channel as a 3D coordinate in space, thus creating not a table, but a cube. In this way we will have much more color information since we are navigating in the space made up of the three colors. For example, an 8-bit LUT would have 2 ⁸ x2 ⁸ x2 ⁸ = 16, 777, 216 colors. Doing the same with a 10-bit panel, we can represent 1024x1024x1024 colors, that is, 1, 073, 741, 824 colors.

For calibration purposes, LUT curves allow us to calibrate the monitor with many more color tones. In order to obtain maximum fidelity and color precision in the design programs that use them.

Install and configure DisplayCAL

With the most important concepts already seen, we will proceed at once to calibrate the monitor. Let's start by downloading the program and installing it in a normal and current way on our computer.

First steps to install the colorimeter

When we install and open it for the first time, it will ask us to install the Argyll libraries. We agree that the program will automatically download them from the repository and install them automatically.

Now we are located on the main screen of the program and we are presented with two important sections: the Screen, where our monitor should be perfectly detected, and the Instrument / Port section, where our colorimeter will appear.

With the libraries that we have previously installed, the software should detect it automatically. In the event that we have a Datacolor Spyder, we will go to the Tools -> Instrument -> Activate Spyder colorimeter menu … If we have an X-Rite it will be detected automatically.

A very important step, which must at least be done with X-Rite colorimeters, is to close the device's own background application. This will only have to be done if we have also installed this one, since its own drivers will conflict with those of DisplaCAL and when calibrating it will give us an error.

We will go to the Task Manager and locate the program in question. We will simply hit Delete and the task will finish.

It is still recommended to do one more management, and it is about preventing the screen from turning off while we are performing the calibration. In certain cases, the calibration can take a long time, depending on the quality we want, so we will go to the power settings and increase the screen uptime.

Now everything is ready to start.

Generic settings to calibrate monitor

Now, yes, we are ready to calibrate the monitor, so let's see the most important options that we must take into account in DisplayCAL.

• Unattended calibration: this function is in the options -> advanced section. We will activate the option “ Allow to skip the self-calibration of the instrument ”. It only works with some X-Rite colorimeters, while the rest may ask us to make manual adjustments to the device while calibrating.

• Observer: We recommend keeping it by default in CIE 1931 2 ^or to use the standard formula in calculating calibration values. White point: as we have already mentioned, the color temperature considered neutral is 6500K, or daylight. The lower it is, the more orange the colors will be, and the higher they are, the more blue. White Level: This is basically the luminance or brightness at which we want to calibrate the monitor. We can leave the option "Native" if we are happy with the current brightness of our monitor, or put a value ourselves. This will be useful for especially bright or especially dark rooms. Black point correction: this option will be left at 0% if we have a good performance monitor with a high level of black quality, for example, an IPS panel. Calibration speed: it is not a fundamental option, but it will depend on the time it takes for the calibration and, in part, its quality.

• Profile type: we recommend placing this option in Curves + matrix for a normal calibration. LUT curves are intended for high-performance monitors and powerful equipment that are capable of working with a high color density in design programs. Gamma: The tone curve must be configured as the factory monitor is calibrated. In most of them there will be an option " Gamma " in the OSD menu where a value will appear. It will be that we should select for calibration.

Calibrate monitor step by step

If you want to get a results report from the monitor before calibrating it, go to the results verification section later in the tutorial.

After having all the adjustments to our liking, it is time to proceed to calibrate the monitor. So we will place the colorimeter right in the center of the screen and click on " Calibrate and profile... ". We must make sure that the device has the lens uncovered and is inside the box that will appear in the center of the screen.

We will start the calibration, where a carousel of colors will be displayed that will serve to establish a previous calibration of the colorimeter. At this point, if the calibration is not neglected, we may have to interact with the colorimeter as the program indicates and according to our model.

After this, we will get to a new interactive monitor setting window, we will start the measurement. The function of this screen is to tell us how well adjusted the RGB and brightness levels of the monitor are according to our preferences. It will be ideal when all the bars are right where the indicator arrows are.

To adjust these bars we will need to go into the OSD menu of the monitor itself and readjust the RGB tones until we get the best result we can. We will do the same with the shine. When we achieve a good adjustment, or if we cannot do it because the screen does not have this option (portable), we will click on " Stop measurement " and then " Continue with the calibration ".

Finishing the calibration

After a process that may last more or less depending on the chosen parameters and the speed of the colorimeter itself, we will be in the results phase.

At this point, a window will appear in which a balance of results will be shown showing the coverage in the different main color spaces. This will be very interesting to check the capacity of our monitor and buy them with the specifications given by the manufacturer.

We will go a little further and click on " show profile information ". Thus a new window will appear showing these results graphically. We can choose a certain CIE diagram to see its coverage and different representations of the color space. The easiest to understand is the CIE xy which represents the values ​​with the normal and current visible spectrum.

When we have seen the results, we will click on Install the profile if we agree with it, in order to definitively fix the configuration of our monitor.

Verification of results

Now (or before) the results verification phase arrives, in them, we can see, for example, what the Delta E of our monitor is like, its uniformity or the approximate Gamma value of it. This can be done before calibration and afterwards to check the improvements we have obtained.

These options are almost all in the last section of the program, the " Verification " section. Here we will select the ICC file created by the program after the calibration or we will choose “Current” if we have not yet calibrated, in order to show the results with the configuration in which the monitor currently has.

In the dropdown list below, we have a bunch of report types, albeit all similar. We can choose for example " Profile verification settings chart " and just below choose the reference color space to buy, for example, DCI-P3. Now we just have to give " Measurement report..."

After a process similar to that of calibration, we will see in an HTML document the results for the chosen color space. We see that the Delta E is very good in the entire color palette, a good way to know if our monitor is now well calibrated.

You can try different reports to see the different results and explore possibilities, the more, the better.

We still have more options, going to the Tools -> Report tab. There, we can do a screen uniformity test to find out the brightness levels of the screen and how they are distributed throughout the panel.

Likewise, we will be able to make a non-calibrated or calibrated screen report to know some important values ​​about the monitor before starting the calibration. For example, your current color temperature, gamma, contrast, or current brightness to choose as an option in “white level”. It even estimates what the color depth of the monitor is.

19: 05: 17, 383 Setting up the instrument 19: 05: 17, 383 Product Name: Colormunki Display 19: 05: 17, 383 Black level = 0.0324 cd / m ^ 2 19: 05: 17, 383 50% level = 24.32 cd / m ^ 2 19: 05: 17, 383 White level = 113.36 cd / m ^ 2 19: 05: 17, 383 Approx. gamma = 2.22 19: 05: 17, 383 Contrast ratio = 3503: 1 19: 05: 17, 383 White Visual Daylight Temperature = 6341K, DE 2K to locus = 3.4 19: 05: 17, 383 Effective Video LUT entry depth seems to be 8 bits

Other programs including colorimeters

In addition to DisplayCAL, there are many other calibration programs on the market, both free and included with the colorimeter, and paid, such as the prestigious CaIMAN.

An example of this are the programs that bring the X-Rite colorimeters. Of course, the more expensive the equipment, the more complete the program will be. The first of them corresponds to the ColorMunki Display, and the truth is that it is too basic, not providing just post-calibration information. Meanwhile the one that brings the top version, the i1 DisplayPro is much more complete and provides many more options and results.

Conclusion on calibrating monitor successfully

This is our tutorial on how to calibrate your monitor step by step. As you can see, it is not a very complex task, although we do have to invest some money in a colorimeter.

That is why to calibrate the monitor once in a lifetime it is not going to be worth buying a colorimeter. On the contrary, if we are designers and we want to have all our monitors ready, it will be an investment in the future.

The more you use the program, the clearer you will have its operation and the options it offers us. A good way to compare its features is to also use the colorimeter's own, to contrast information from the different color ICC profiles created.

Now, we leave you with some interesting tutorials related to the topic:

What monitor do you have? Have you ever heard of colorimeters and calibration before ?