Document.save_snapshot(). This performs a special incremental save that includes all journalled updates so far. If its journal is saved at the same time (immediately after the document snapshot), then document operations or to continue journalled updates – just as if there had been no interruption. • The snapshot PDF is a valid PDF in every aspect and fully usable. If the document is however changed in any way journal file, then a desynchronization will take place and the journal is rendered unusable. • Snapshot files are structured like incremental updates. Nevertheless, the internal journalling logic requires