Why: Calibrating a Screen is Insufficient When Creating a Photograph
You have certainly often heard that to develop your photographs well, you need to calibrate your screen.
This is a necessary but insufficient condition to print your photos correctly.
In this article, I will explain why.
Why: Calibrating a Screen
The correct calibration of a screen is the guarantee that your photos will be seen in the same way on another calibrated screen anywhere in the world.
To create an artistic or illustrative photograph correctly, you must calibrate your screen properly. This is an essential step during the development phase of your photos.
As I often say during my photography workshops, a photograph only exists if it is printed on paper, whether it is for a wall display or for a beautiful book.
As long as it is not printed, it is an image. This is the case for a display on a computer screen, a tablet or a mobile phone.
Displaying on a digital medium is only an intermediate step. To me, it is not essential.
Screen manufacturers produce devices that are often very bright, high contrast. The photographs displayed are often cold. Indeed, photographers are a small minority. Most screen users are content to play games, consult websites or use office applications. The original settings are made to satisfy these users.
But as a photographer, you have other more specific needs because your photographs are going to be printed.
When editing a photograph, you want to be able to display colors, contrasts and tones correctly.
For example, you do not want exuberant colors like tablets can produce. They are certainly flattering to the eye, but they are incompatible with quality paper printing.
For this reason, it is necessary to calibrate the screen. Colors, contrasts and tones will be displayed in relation to standard values.
But as for me, the most important thing for me is the printing phase. But to print a photo correctly, the calibration of a screen is insufficient.
Calibrating a Screen is the First Step in the Development Process
As I mentioned in the article about developing artistic photography, the use of software is essential for you to show your vision of the world through your photos.
The development will allow you to strengthen your photographic approach. This is its only function.
But before using software, it is essential to properly calibrate the screen you will use during the development process.
If this step is not performed correctly, the development of colors, tones, and contrasts will not be correct.
If you give your picture to someone who has a calibrated screen, the result will be totally different from what you see.
The Principle of Screen Calibration
To properly calibrate a display, you must use a calibration device.
A calibration with eyes will not give you a good result because it will be subjective.
A calibration device is a small electronic device sold by specialized companies. It connects to a computer via a USB cable. It is placed on the screen for the calibration phase. When the device is purchased, the manufacturer supplies a special application to the consumer so that they can control the probe during the entire calibration phase.
To begin, you will enter some quite simple data, perform one or two operations. Then the software will drive the device for calibration.
When all operations are complete, the application will generate a file called an ICC profile that contains the monitor's characteristics.
This ICC profile will be loaded by the computer's operating system at each boot. This profile will provide information to the video card to correctly display colors, contrast, and tones.
The goals of proper calibration are:
- Override the manufacturer's default settings for a display.
- To display the correct level of contrast and brightness in the widest possible range of colors.
Let me take the example of the grey which in the RGB gamut has the value 128. If the screen is calibrated correctly, it will display a true gray. If the screen is not calibrated correctly, the gray will shoot the orange ones.
Why Eyes Alone Inhibit Good Calibration
As I have just described, a calibration device is required to properly calibrate a screen. Your eye is not suitable for this operation.
On the one hand, it is not able to read a color without having a comparison element.
On the other hand, it is not able to know the brightness level of a screen.
Even when the light is low, it is able to detect details in a scene.
If you observe a dark photo on a screen, you will be able to see details. Your eyes will think that the tones are correct. It is when you print that you will realize that the shadows or blacks are very dark.
Calibration in Practice
Calibrating a computer screen has become quite easy. Application editors have made great strides in software ergonomics and interface.
The first step in calibration is configuration. You have to set the color temperature, gamma, contrast value, maximum brightness, also called the white point.
Once these values are provided in the device control application, calculations will be performed for a few minutes. This step is called characterization. At the end of the process, the application asks you to specify a name for a data file. This is the famous ICC file I mentioned earlier. It will be loaded each time you start your computer.
One of the essential points you must respect is to set the amount of light emitted by the screen between 80 and 100 cd/m2 (candelas per square meter). A higher value will cause problems when printing.
After a screen has been profiled (or characterized or calibrated) the settings must not be modified any more. If this happens, you must redo a calibration.
I recommend that you perform a full calibration every two weeks as the settings change by themselves. These are not great variations, but quality developments require perfect quality from the beginning to the end of the post processing workflow.
Proper Calibration is Not a Guarantee for Correct Impressions
Correctly calibrating your monitor only allows you to ensure that the photos you develop will be viewed in the same way on all monitors worldwide and are properly calibrated.
If you use another way to view your photos, such as a video projector or a printer, you may be disappointed with the result.
Let us take the specific case of using a printer. Printing is the penultimate step in the workflow of creating a photograph.
If you print your developed photograph with a calibrated screen, I bet you that your printed photo will be dark. This is because paper absorbs light while a screen emits light.
When printing a picture, there is usually between 1 and 2 EV of light missing. Shadows are often dark. The whole picture becomes flat.
If you have your own printer, it must be calibrated. This will ensure that the result is consistent with the one you see on the screen.
The problem comes from the prints made by specialized laboratories. You cannot intervene in the printing process. You cannot calibrate printers.
In addition, if you use the services of a generalist laboratory, you will not be sure to have your photographs printed by the same printers with each order.
This is a real problem because it is impossible to create a rule for managing brightness and apply it every time you want prints. Everything is unpredictable.
That is why I always use the services of specialized laboratories with whom I can speak directly. I always ask for printer marks and printing procedures.
But in both cases, whether it is a specialized laboratory or a generalist, the light of the photograph will have to be increased so that it can be printed correctly.
The problem is how many EVs to increase the light. Too high a value may cause overexposure of certain areas. Too low a value will still result in a dark picture.
For this reason, you must request tests by requesting a "bon à tirer" (whose acronym is BAT). This BAT is a proof of your final prints.
It is for this reason that you must ask for tests by asking a proof of your final prints. The printer selects a portion of the photo and sends it to you for verification. This process should be repeated as many times as necessary until the desired results are achieved. The proof can be expensive, but it is necessary. Once the photo is printed and glued onto a support, the cost is quite high.
I will not go into detail to print a photograph. That will be the subject of another article.
The correct calibration of a screen is the first step in the development of photographs : artistic or illustrative.
However, if your photographs are to be used for other media, such as a printer, other processes must be initiated for the image to be properly displayed.
If you wish to create artistic prints, you must place massive focus on this crucial phase if you want to highlight your photographic vision accurately.