Conditional Formatting Cells based on a formula in the cell, not the value of the cell?

Hello,

I am wondering if anyone can tell me how to make conditional formatting based on a formula in a cell, not the value of the cell?

To give some background:

I have a sheet that compares financial information of various companies (let's call it 'Sheet 1') using a vlookup to a sheet that pulls from a database (let's call it 'Sheet 2'). The last column in 'Sheet 1' is a column with my company's information. Most of the financial information for my company comes from a 'Sheet 3' that contains corporate model information. Some of the financial information on my company that is not found in 'Sheet 3' is pulled from the database 'Sheet 2' using a vlookup. I want to set up conditional formatting so that I can see which cells have been pulled from 'Sheet 2' (formula using a vlookup) and which cells have been pulled from 'Sheet 3' (just a direct reference to the exact cell).

If any one could give me some insight into how to solve this problem I would really appreciate it!

Thank you!!

Are you suggesting that you can set up a CF based on where the value is pulled from? If that is the case, would you please elaborate on how to do that?

If you mean just CF based on the value in the cell that won't work because it's different for every cell and in many cases whether it is pulled from Sheet 2 or Sheet 3 the numbers could be the same.