It is not possible with the watermarking feature. But you can achieve something visually identical with page background images.

Try to override getPageBackgroundImageUrl(int pageNumber) method as it is done for getHtmlTemplate() method in the code snippet below (implementing the logic you need):

[language=java:2rrc4msf]PD4PageMark footer = new PD4PageMark() {
public String getHtmlTemplate(int pageNumber) {
if ( pageNumber % 2 == 0 ) {
return “some left aligned stuff…”;
} else {
return “some right aligned stuff…”;