Hi Youna;

   I've been doing this for decades with PB. In this case, the DataWindow is your friend. The two key features of the DWO for accomplishing watermarks are: A) Transparency and B) Layers (aka Bands).

   The first step is to place the text, image, etc controls (even another DWO) into to primary DWO's "background" layer that creates the actual watermark effect. Make sure that these controls are set to a very light grey.

  Next, add your regular controls to the "Band" layer but set their transparency to 50% so that the "background" layered objects (watermark) shows through.

  The alternate approach is to place your data in the Band layer using 0% transparency (normal default). Then add the watermark objects into the "Foreground" layer but make them 50% plus transparent so that the data seems to bleed through. This will also create the watermark illusion.

  Note that the 1st approach is also excellent for pre-printed business forms where the scanned form sits into the background layer with the data placed over the appropriate sections in the band layer over the form in the background layer.

 Hope that makes sense. Now if the DWO displays the data + watermark properly, the resulting SaveAs(PDF!) will render an exact watermarked PDF file.

Hope that makes sense. 

Tip: Use the "Escapement" property to rotate the watermark text. For example the word "confidential" displayed diagonally in the DWO & thus in the resulting PDF.

Regards ... Chris 

Chris' suggestions are excellent and I encourage you to investigate and experiment. Using the Background and Foreground layers is not something that every PB developer is familiar with.

Tip: When working with a DWObject assigned to either the background or foreground layers, pretend the normal bands (header, detail, footer, etc.) are not there. Even though the bands are visible and you can continue to interact with them and with objects assigned to the Band layer, the background and foreground layers are each like a sheet of transparency film that covers the entire Painter. With a little experimentation, you'll quickly see what I mean.

If I may also provide some additional information about Escapement:

This property is found at the bottom of the "Font" tab in the Properties pane of the DW Painter (See PB Help topic "Font.Escapement property" for more information). You have to set its value using the Expression dialog window, but the expression can be simply an integer value. Escapement is expressed in tenths of a degree (450 = 45 degrees). Positive rotation is counter-clockwise. Normally, the rotation is applied to the baseline of the text, but this depends on the text alignment setting (refer to Help).

Please note that escapement is only applied/seen in the DW Painter in the preview pane (and of course, at runtime)... in other words, the text DWObject(s) that have escapement will appear in the Painter as normal, with no escapement. This is the way it works. I believe this is why you are required to define escapement as an expression.

Good luck!

Also kindly watch this page 

https://docs.appeon.com/pb/whats_new/New_PDFBuilder_objects.html

Where Appeon is enhancing PDF features... may be watermark could be added in next releases...

How would I use a watermark from a TX Text Control document? Currently I need a pdf-printer to underlay a background...