Conditional Format if cell is empty?

JesusTrance wrote:
Is it possible to apply a conditional format to an empty cell? Say, to make the cell fill color red?

Redefine the problem: "Is it possible to apply a conditional format that will make a cell's fill colour change to white if the cell contains anything?"

In the example, Fill for cells B2:B5 has been set to red.
Conditional rule for B2 and formulas for C2:C5 shown on the table. Yellow chosen for example. Choose a white conditional fill for "regular" appearence.


Entering 0 in C2 (rather than using the formula) makes the solution simpler. Filling B2 down to B5 using the handle copies the conditional rule into the rest of the cells, and leaves the cell reference in the rule as "C2". As Numbers evaluates an empty cell as zero, comparing the cell to a cell containing an entered zero (or to an empty cell) will also trigger the condition.

The trigger cell may be placed on a separate table and hidden if desired.

Regards,
Barry