Creating scanner or camera profiles
There are several types of ICC profiles depending on the kind of equipment that you wish to characterise.
We will find input profiles for the acquisition tools, such as scanners and cameras. Then the monitor profiles that will allow the colours in your files to be displayed correctly on a well calibrated screen. And finally output profiles, corresponding to the working space of the printing system. Different printing systems use different working space. For instance RGB is used for, the photographic printing systems (such as Durst Lambda, Fuji Frontier) and inkjet printers running on native drivers supplied by their manufacturers. CMYK is used in the proofing systems and offset presses as well as some digital presses.
Creating input profiles
To create input ICC profiles, specific charts are needed with known measurements. These charts are called IT8 for scanners and ColorChecker or ColorXact for cameras. The right piece of software allows the values seen by your scanner or camera to be compared to the “right” values as it should have seen them. By capturing the actual values on the chart and from that form a translation table, ICC profiles can be created, which allow the colours as they are seen by the scanner to be converted into the values as it should have seen them.
Creating monitor profiles
In fact the computer screen is the only tool that must both be calibrated and characterised in the same operation. To do so you have calibration software and a probe, a colour meter that allows the measurements to be taken on the surface of the monitor. The new graphics arts screens, connected to your computer by DVI allow you to calibrate and create a profile automatically as it is the software that adjusts the screen settings to measurements made by the colour meter on the screen.
The standard values generally accepted for a modern LCD screen are:
White point = 5000K (the graphics standard)
Contrast = 2.2
Brightness = 100 cd/m2 for proofing, 120cd/m2 for retouching images
Creating printer profiles
To create an output profile, a chart that is generated by the profile calibration software, must be printed with your printing system and read using a measuring piece of equipment called a spectrophotometer.
The software compares the values in the original file to the ones measured on the printed document and creates a translation table which allows you to find out what value is required to obtain the “right colour” for each colour in your files when printing.
The printer profile can still be used while the printing system is in the fixed calibration stage during the creation of the profile.
It is still a profile and characterises a system made up of: the calibrated press (or printer) + the selected paper + the selected ink.