No one has ever done such a miracle with a chronicle of 100 years ago. Peter Jackson made a super-realistic chronicle of the First World War and this is really something incredible.
Old films show a picture of 10−16 frames per second - they are jerky or accelerated and it does not look realistic. Peter Jackson, along with his team, added a chronicle of new shots to fill the voids and make it smooth. The picture has become similar to the modern - it gave a striking and even shocking effect. If you don’t know that the professionals have worked on the film, you’ll add the impression that we’re facing a reconstruction. And thanks to the work of lip-reading specialists, it became possible to voice what the soldiers say.
While the film “They Shall not Grow Old” without translation (HD quality), the effect described above begins with the 25th minute of the film.