At Hong Kong Rescue we use a variety of techniques to restore video and author Blu-ray discs. It's a painstaking process but through the combination of different methods and an eye for detail, we're able to do amazing things.
The tools we use:
Digital Vision Phoenix
The Pixel Farm's PFClean
Topaz Video Enhance AI
Topaz Sharpen AI
...and way too many additional programs and applications to name all of them.
A lot of the video we work with is less than pristine to say the least. Often we work with transfers scanned from heavily damaged 35mm prints that haven't been stored well.
This leaves a lot of dirt, dust and damage that we try to clean up.
For this task, we primarily use two professional restoration programs: Phoenix and PFClean.
We use Phoenix primarily for it's superior automatic dirt removal algorithms that are quite effective at cleaning up a lot of dirt and dust automatically without causing artifacts. It's not perfect, but it is generally able to remove 70-80% of dirt which makes the rest manageable.
Then we us PFClean for all the manual work. This is painstaking, frame-by-frame stuff. We'll typically load up five minute segments at a time in TIFF of DPX image sequences and run a loop looking for dirt, dust, scratches and broken frames and then repairing them using PFClean's manual filters.
Using this process, we're usually able to achieve extremely clean, very detailed transfers even when we don't have good sources to work from.
For example, look at what we were able to achieve working with the Japanese version of Wheels on Meals:
We often work with video where the color grading is incorrect. Sometimes this is due to film wear, other times it's the result of studio's ignoring the director's original intent and messing with the look of the video.
Sometimes we have a good quality transfer that is edited and we'll have to splice in scenes from another source. In that case, we have to color grade the sources to match.
One example where we employed color grading is with our recent release of Supercop. L'Immagine Ritrovata scanned and restored the video in 4K recently and, while they did an admirable job, the colors were extremely faded and very yellow. This is probably due to the film elements they had to work with. Still, we did our best to restore the original luster of the colors using the best reference we could find.
Here's an example:
What we do is find a reference where the colors look at close to the original theatrical release as possible and then export a sample frame of the Target and the Reference. Same scene, cropped the exact same way.
Then we use Dr Dre's Color Matching Tool to create a LUT that will match the target to the reference.
We usually do this on a scene-by-scene basis.
Occasionally we'll then tweak the white balance to make sure everything looks good before the final export.
On The Audio:
We have consistently found that the best source for the original audio tracks for older Hong Kong films can be found on laserdisc releases. There's no technical reason why laserdiscs should sound superior to the DVD and Blu-ray releases that followed, but I have a few theories.
First, laserdiscs nearly always used uncompressed PCM audio, same as the CD format. For older films where the audio tracks were designed for Mono or Stereo, this is all you would need.
Once DVDs became popular, they tended to use lossy Dolby tracks that were heavily compressed.
Another thing I suspect to be a factor is that the original film elements tend to degrade over time, especially since the Hong Kong film industry didn't take care of their classic films as much as they should have.
So, even when Blu-ray came along with technical specifications that were far greater than laserdisc, the sources that companies licensed from Fortune Star or whoever, had likely degraded over the years and, even if the audio was encoded losslessly, the source likely had inherent problems that made it sound subjectively worse.
By contrast, the laserdisc releases came out right after the films were made and therefore had pristine and new elements to work from.
Regardless of the explanation, our releases usually use a laserdisc source for the default audio track because they tend to sound better.
Each project is different and poses unique challenges. There are many more techniques we employ for our releases and I may add to this page with additional details.
Still, I hope this gives a good idea of how we work and what we're able to do.