Remastering Film, the perils of DNR

Last night, I watched the first UK broadcast of Star Trek The Next Generation (ST:TNG) in HD. The original negatives, stored in a salt mine, have been re-scanned and the individual SFX elements re-composited in HD. This was an epic undertaking, and where possible used the original FX elements. Where these could not be located, CGI was used to re-create the FX sequence.

Season 1 of ST:TNG was originally filmed on 35mm film (not video) and was finished on 1-inch analog tape (the rest were digital D1). This and the fact that the show was then composited on video using the NTSC standard may account for the pinkish tint that plagues all the season 1 episodes on DVD.

Star Trek The Next Generation Blu Ray

OK, so this comparison is not HD resolution. But even so, the improved colour timing of the blu-ray (right) compared to the pink-hued DVD is obvious. Also, even at this resolution, the deflector array is sharper and the windows better defined on the Enterprise.

The remastering for the Blu-Ray release makes the DVD’s look like dodgy bootleg copies. It really is more than just ‘cleaning the windscreen’ and showing a bit more detail. The show has been lovingly restored from the 0-negative and properly colour corrected, so that skin tones are natural and blacks are black and not gray.

Some will complain that whilst the image presented is much sharper, what is noticeable now is a graininess in certain scenes. This would have been mitigated when viewed in Standard Definition but has been highlighted by the upgrading process. It is absolutely correct that the film grain is left in place, which brings me on to the subject of this post, a scary process called DNR.

One of the common misconceptions with Blu-ray is that it only offers a significant advantage over DVD if the film was shot relatively recently. This is wrong, 35mm film can be scanned at 4K (4,000pixels – ish), which is way higher than the Blu-Ray format can handle. Check out The Wizard of Oz on blu-ray for an example of how great an older film can look:

The amount of film grain is usually higher in older films due to the film stock that was used. Sometimes however, the director of a movie will want a more grainy image. It’s an artistic choice used in the Bourne Films to create a gritty and realistic feel.

Dynamic Noise Reduction (DNR) is a filter that can be applied to an image (or frame of film) and effectively smooths (or averages) in order to de-speckle and reduce grain. This process, when used sympathetically can be seen to improve picture quality.

However, recent re-releases of some significant films on Blu-Ray have been very poor quality due to excessive use of DNR. Examples include: The Predator, Terminator, Star Trek IV, Total Recall, The Thing, The Fifth Element, Star Wars, Episode 1: The Phantom Menace and many more…The problem is that excessive DNR leads to waxy looking faces and the quality is further compromised because then the image has to have an edge detection filter applied to attempt to create the original sharpness.

In the very worst cases (see image from Predator below), you are better off with the origninal DVD! Note that the re-mastered DVD will also have had the DNR applied and will look terrible. Also note that the contrast and colour saturation is different to how the director originally intended.

Blu-Ray (left) is sharper – but notice how in the left image, Arnold’s face looks waxy and fake compared to DVD (right). His stubble has lost its texture and it no longer looks like film – more like CG – smooth and unrealistic.

The first time I really noticed the DNR issue was with the DVD release of ‘Lost In Space’ where terrible artifacts caused by DNR are visible (especially in dark scenes). With blu-ray discs, we are plunking down a large chunk of cash in comparison to the DVD and the video quality should reflect that.  I’d check out before stumping up for an older ‘remastered’ movie.

Star Trek has been restored beautifully though, and we should be grateful to Paramount, who could have saved a lot of money by simply up-scaling the picture. Sadly, for some shows, like Farscape, the original negative is lost. The up-scaled picture is sadly wanting, and appears very soft. Babylon 5 will likely never be released on blu-ray, unfortunately, as its CG work only exists in low resolution renders and would have to be completely re-done.


2 thoughts on “Remastering Film, the perils of DNR

  1. They could re-do the B5 CGI though, they are redoing some of the TNG scenes with CGI, they did the whole of TOS with CGI, … it can be done, the main problem is probably that B5 doesn’t have the guaranteed sales that Star Trek has, so it may not make financial sense. Then again CGI is getting cheaper and cheaper, so… who knows.

    • Lets hope you’re right, B5 certainly has a hardcore fanbase that would lap it up. Who knows, maybe it would even attract more fans. There must be lots of CG artists out there that would enjoy that labor of love!

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