Here's an example of how to make a simple text-based watermark for your document.
WARNING! This code only works with non-test mode documents. Test-mode watermarks will override this watermark.
<!DOCTYPE html>
<html>
<head>
<title>Watermark Test</title>
<style type="text/css">
.break-after {
page-break-after: always;
}
#watermark {
flow: static(watermarkflow);
font-size: 120px;
opacity: 0.5;
transform: rotate(-30deg);
text-align: center;
}
@page {
@prince-overlay {
content: flow(watermarkflow)
}
}
</style>
</head>
<body>
<div id="watermark">PREVIEW</div>
<div class="break-after">Page 1</div>
<div class="break-after">Page 2</div>
<div class="break-after">Page 3</div>
</body>
</html>