Create a profil from a calibration

This tutorial explain how to create a custom profil for your own use case with a calibration step.

The printer drivers and some RIPs do not correctly optimize the amount of ink deposited on the paper.

This has the effect of creating profiles that consumes more ink, less accurate colorimetric and more sensitive to metamerism on media such as sublimation for example.

The other advantage of creating a calibration before characterizing the print media is the ability to adapt the profile made for use on another printer of the same type, or to regain a drift due to your printer without having to redo all the characterization (the icc profile).

That is, by printing and measuring only the calibration range, it is possible to quickly correct a drift during printing.

For optimum results, follow the procedure explained below

1. Create a calibration

Let's start by clicking the Printer button to start the procedure

We will now start by creating the calibration (.cal)

Select "New configuration" then "Validate".

Give a name to this calibration
Select your Spectrophotometer (If it is already connected, it will be automatically selected)

If you use an I1 Studio or a ColorMunki Spectrophotometer, You can use two kind of target:

Big patches to read the target directly without a ruler.
Small patches to read the target with a ruler.

The path

Before to start, it's should be useful to have a look on the Path in the upper side to browse into the different steps during the icc profile factory.

Stop : click on "Stop" to exit the procedure
Calibration: Select RGB or CMYK mode
Configuration: Parameter to create the chart
Mire Creation : Get the chart for printing
Printing : Get target for printing
Read Target : Target Reading

Calibration

Select the RGB or CMYK mode and start the calibration.

The colorimetric mode you will select must be the same as the icc profile you will achieve later.

Choose the Auto ink limit method
- Click Yes for an automatic ink limit
- Click No to control manually the amount of ink for each ink.

Remember that for printer drivers, profiles are made in RGB and for RIPs it can be CMYK or RGB.

You have the option of customizing the calibration pattern, but the default format is usually sufficient.

Click "Next" to continue the procedure.

Configuration

Mire Creation

Click the "Save Target" button to export the Tiff files for printing.

All you need to do is to select a file where you want to save these Tiff files.

Printing

You must print the ranges without color management. To help you print patterns, you can do the following: Printing chart

Read Target

Make sure the spectrophotometer is connected, then click on "Start calibration.

When your instrument is calibrated, a new window appears. Click on the "I'm ready" button to start reading the range.

The range is measured from the side of the letter to the opposite side. It is necessary to leave a white space on each side of the measured line because the measurement starts with the white of the paper and ends on the white of the opposite paper.

The measurement starts with the line "A", then measure the line corresponding to the line highlighted in blue on your screen.

When the test pattern is measured, the "Next" button becomes active and you can click it to continue the procedure.

Note that you can return to a line to re-measure by moving with the up and down arrows, before clicking "Next" to save the calibration file in the left column.

It's possible to check the calibration curve by clicking right on the calibration file and select "Open graph" or to click on the blue button "Show linearization".

When the calibration is complete, we will start the characterization step, ie the creation of the icc profile.

2. Create a characterization

Let's start by selecting the "Characterization" icon, then "New Configuration" then click on "Next".

Write the name of your Icc Profile, then select the color mode.

Generally, you will select the RGB mode to create profile to print from Photoshop or also application.

Now, if you print though a professional RIP (like EFI, Caldera, Onyx, Ergosoft, Wasatch, neoStampa, Epson Edge Print, etc...) it may be possible that you need to create your icc profile into the CMYK mode.

Settings Area

Choose the number of White Patch Test.

The white patches are usually very important in establishing white point that the ICC data is made relative to, so it improves robustness to use more than a single point.

Choose the number of Patches

This parameter sets the number of full spread test patches. Full spread patches are distributed according to the default or chosen algorithm. The default algorithm will optimize the point locations to minimize the distance from any point in device space, to the nearest sample point. This is called Optimized Farthest Point Sampling (OFPS) . This can be overridden by specifying the kind of target.

Choose the format of your target and the orientation

Select page format A4, A3, A2, Letter, Legal, 4x6, 11x17 or Custom
Orientation
Margins
Patches format
Resolution of the Target (Tiff files)

Import calibration file

Drag and Drop the new calibration file to the area "Import Calibration".

The target will be automatically optimized to be adapting to the calibration curve.

Then click "Next"

Click on the "Save target" button to export Tiff files for printing.

You have to print targets with no color management. To help you to print targets you can follow the procedure: Printing chart.

Then click "Next".

Read the targets

You have to connect your spectrophotometer to start the process to create the icc profile.

Put you spectrophotometer on the calibration position, then click on "Start calibration" bar, then click on "Next" button to start the measure.

Now it's time to start the reading!

When the "Target reading" windows will appear, you have to click on "I'm ready" button and you can take your spectrophotometer to start the measurement.

The range is measured from the side of the letter to the opposite side.

It is necessary to leave a white space on each side of the measured line because the measurement starts with the white of the paper and ends on the white of the opposite paper.

The measurement starts with the line "A", then measure the line corresponding to the line highlighted in blue on your screen.

When the line is measured, a check mark appears on the right.

Before and after the line reading, you can hear a bip to indicate when you have to start the scanning and when the line scanning is done.

You can visually check if there were no errors during the line measurement, comparing the upper and lower color of the measured patches.

If during the procedure you have a wrong reading, you can "Move Forward" or "Move Backward" with the up or down arrow on your keyboard.

When you have read a line, Coraye will make you read the next unread line.

Coraye detect automatically if you have commit a mistake during reading and display a warning message.

3. Calculate the Profile

Before to calculate the profile you can choose some options:

The quality of your profile Choose your illuminant, D50, D65, etc...

If you have selected CMYK color mode at the beginning, you will have more option to create your Icc Profile, you can play with the black GCR / UCR option into the graph and the inks limit.

When you setting is ok, click on "Calculate Profile" blue button to start the calculation.

When the calculation is done, the icc profile will appear in the left column and it internal name will be: Profile_Name [Calibration_Name] and in the lower right corner, you will see the option "Has a calibration" et it should be "Yes".