How to: Watermarks in Excel 2007
Watermarking your Excel workbooks is useful for indicating to those viewing your data that a workbook is only a draft, or that the workbook contains proprietary data. Excel 2007 doesn't a have command specifically for creating or inserting a watermark graphic, but you can simulate this functionality by installing a graphic into your workbook's header or footer. Note that you won't see the graphic unless you're in Excel's "Page layout" viewing mode.
Click the "Page Layout" tab, then click the small down arrow at the bottom right of the "Page setup" panel. Excel will display a dialog box with options for setting the header and footer of your workbook. Inserting a picture in a header creates a watermark for the workbook.
Click the "Header/Footer" tab, then click the "Custom header" button. Excel will display a dialog box allowing you to specify different headers for the left, right and middle sections of your workbook.
Click in the "Center" text box, then click the icon above the text box that appears as a mountain with a rising sun over it. This button is the "Insert picture" tool.
Click the button just mentioned, then use the controls in the "Insert" dialog box that appears to move to a folder on your hard drive containing a picture file you would like to use as a watermark.
Click the picture file to select it, then click the dialog box's "Insert" button to load the picture into the header for your workbook. Excel will display the text "(Picture)" in the "Center" text box, which indicates it successfully loaded the picture.
Click "OK" to exit the dialog boxes and complete the insertion of the picture into your workbook. Excel will not display the picture while in draft view, which Excel documentation refers to as "Normal" view.
Click the "View" tab, then click the "Page layout" button of the "Workbook views" panel. Excel will display the picture you inserted in the header's center section, but only on the first page of the preview.
Click a cell on any of the pages where Excel displays the text "Click to add data." Excel will insert your watermark graphic onto the page you clicked.