Do you want the field background to fill with color or the text that appears in the field to change color.
Both are options you can select in a conditional format dialog. Right Click the field while in layout mode and select Conditional format. Use the controls in the dialog to set up your conditional format formula:
YourTable::Field < Get ( CurrentDate )
Then there are options in the bottom right corner of the dialog box for specifying either the text color or the fill color.
This helps. Now I have found the Dutch translation, it is called "Voorwaardelijke opmaak". (I don't know who translated this, but it is confusing. I have been searching for more then 3 hours).
If you find that the Dutch language version of FileMaker inadequate, I recommend documenting some of the failures in Report an Issue as a "documentation bug". If FileMaker doesn't get feedback from the Dutch users, they won't know that they need to improve.
I will do that Phil,
Thanks again for your help.