Blast from the past! PhilModJunk = Phil Caulkins. I had a lot of fun editing that journal and wrote most of the articles for one year...
I don't recall all the details of that article but it sounds like something we still use here where I work. (I often figured out a new trick for a client back then and then got paid twice by writing about it in the journal.)
That method does indeed still work in FileMaker, It used global container fields and calculations to return differnt colors as I recall, but in Current Filemaker, we have a nicer option: Conditional Formatting.
You can select the field or fields in your row of records and use a conditional format expression such as:
DayOfWeek (Yourtable::YourDateField) = 1
and specify a fill color for the selected fields when the day of the week is Sunday.
You can create a stack of as many of these conditional formatting expressions as you need colors for days of the week for the same group of fields. No need for container fields and extra calcultion fields returning container as their return types anymore.
Feel free to give a specific example of your needs, if you need specific expressions for your particular day of the week values.