I would like to create a layout that has a simple grid of records, each one the same size, with a common background color.

I created a layout with 4 columns across and I sized the 'body' such that I get 3 rows per page. I put a field in each, and set the background color of the body. So far, so good.

But let's say that there are less than 12 records to print. For all the "missing" records the background is blank as opposed to the background color I set in my layout.

Is there a way to set the background for pages that don't have enough records to fill the page?

Click on the Body tab in the layout and apply your background color to it.

This will not fill the remaining page with colour.

One of the principles to understand is that FMP can only display the data it has. If it has 11 records then it can only display 11 records.

You could fill the remaining page with colour by including a trailing grand summary on the layout; make it almost a whole page big, and set the part options to allow the part to break across the page, and to discard any remaining (I'm not sure of the exact option names).

As Vaughan points out, adding a color to the body doesn't solve the issue (indeed, that's what I already have). The trailing grand summary part didn't fully solve the problem either.

With my grid layout of four across and three down, the trailing grand summary filled any missing rows with a background color, but if there weren't enough records to fill the four slots across the prior row, the empty slots in that row will not have a background color.

Obviously, I could calculate the number of records I have and create dummy records for the ones I'm missing, but I would really prefer to not do this.