Although Color Management is a very extent topic, I will briefly mention three good reasons for an IT8 calibration:
- Color reproduction accuracy
- Scanner aging. Construction parts age and with it the way these devices “see” things. These changes are reflected in light color inaccuracies which can be corrected by generating new color profiles for the scanner
- Scanning conditions change. Things like temperature and humidity might also affect the operation of the scanner, also the internal lamp changes the temperature of the scanner and its components. These might be reflected in light up to stark color changes, these can be corrected by color profiles generated for the specific conditions.
Requirements to IT8 calibrate the scanner
Have the IT8 calibration tool in SilverFast, I should mention, the IT8 calibration is not standard in SilverFast, it is an extra tool that can be purchased as an upgrade to all SilverFast versions where it is not present and is available for all scanners.
An IT8 calibration target and its reference file, both must be stardard conform. Some manufacturers make targets which are conform but their reference file is not (or the other way around). Some packages include this kind of combination. These can not be used to calibrate your scanner with SilverFast (LaserSoft Imaging also sells high quality IT8 targets which allow for automatic IT8 procedure at a reasonable price).
How to IT8 calibrate the scanner
You can IT8 calibrate for positiv reflective (flatbed scanners only) and positive transparent as well as Kodachrome transparent.
There are two possible ways of calibrating and both are pretty straightforward.
Manual calibration must be performed when using targets not produced by LaserSoft Imaging.
In this case the automatic IT8 calibration must be deactivated by openning the options dialogue/automatic panel and unticking the checkbox for Auto-IT8 calibration.
Apply your changes and press “OK” to return to SilverFast
Place your calibration target on the scanner bed or into the slide holder.
On the left side of the preview window you will find the IT8 calibration button.
Press the button to start the process
The small IT8 guide panel appears indicating the steps to follow
Now you will simply adjust the corners of the mask to match the color patches of the IT8 target.
If your target is upside down or back to front you can move the corners to match the current position of the target, just make absolutely sure the white point is positioned onto the white patch of the grescale as well as the black point onto the black patch.
Once you have correctly positioned the mask you can start the IT8 calibration process by pressing the “start” button.
The scanner performs a scan and the guide panel prompts you to choose the location of the reference file, this file is a text file with the value information for every color patch, the file should be somewhere in your computer and should be available before starting the IT8 calibration process to avoid having to interrupt the calibration to download the file.
Once you select the reference file the calibration process will be completed by SilverFast, an information panel shows the delta value of the calibration.
SilverFast will create a new color profile which can then be used later on.
As you can see the process is very simple.
The next post will explain the automatic IT8 calibration using LaserSoft Imaging targets.