Color matching and prediction: color correction tool v1.3 released! — Page 6

Here are some new color corrections for the video sample of the first reel of team negative1's LPP preservation. All these corrections were done with the new color correction algorithm. The model was calibrated on a single frame (8228). The model was then used to predict the corrections for the other frames. Here are the results:

http://screenshotcomparison.com/comparison/142018

http://screenshotcomparison.com/comparison/142019

http://screenshotcomparison.com/comparison/142020

http://screenshotcomparison.com/comparison/142021

http://screenshotcomparison.com/comparison/142022

http://screenshotcomparison.com/comparison/142023

http://screenshotcomparison.com/comparison/142024

Looking good. Even with the problems of their Reel1 sample.

This is a continuation of the color correction discussion in the super resolution thread...

zee944 said:

DrDre said:

confusedgambler said:

DrDre said:

For one reason only, because that's what the colors looked like in 1977. 

Come on, Darth Vader is solid black with no detail left. You can't seriously say that looks right or good or even "what it looked like in '77" Not a chance, no way.

Also,that's not what Mike Verta's version looks like and he has better sources to judge by.

Sorry to dissappoint you, but the reference is a scan of an unfaded Technicolor IB print, corrected to the print. Although there can be variation between prints, the colors are the way they are on the print. The reason detail is lost, is because the GOUT lacks the color depth to show the detail, but on the print it is definitely there. 

I agree with confusedgambler completely.

I'd like to say beforehand that I never trust a scan that I didn't do myself or at least I couldn't compare it with the print I held in my bare hand... I'm just skeptical. I've seen so many times so-called references turning out to be wrong.

But even if these are accurate copies of frames, when they're projected, they look a bit different depending on the projector/light bulb setup... And TV screen is also different. It would look horrible on TV if it looked like the corrected caps. Too deep blacks, burnt out highlights and possible oversaturation (maybe just due to heavy contrast). The untouched GOUT looks better, more natural and (ironically) more film-like. Sure it could use deeper blacks, a bit heavier contrast, but not that much.

If you're sure those scans are consistent with each other, then the colors could be used, but the luma levels are either should be disregarded or fixed by reducing the contrast. One setting for the whole footage. In my opinion, of course.

I also think the color matching script didn't handle this well, I don't think those artifacts particularly visible on the Obi-Wan comparison should be there.

The scans come from a reliable source, and look perfectly fine on HDTV. However, there are a couple of things to consider:

1) The GOUT's color depth is very limited, so although it is possible to match the colors, the color depth cannot be increased. This will result in artifacts. 

2) The GOUT is very noisy. As for the decreased color depth, the noise leads to artifacts, such as in the Obi-Wan frame. This has nothing to do with the algorithm. 

In short, crap in is crap out. 

Applying the corrections to the bluray leads to a much better result, with less artifacts, but even the bluray suffers from lack of color depth, digital noise, and crushed blacks:

 Indeed, these look much 'healther' than the GOUT equivalents. Again, I'll use the disclaimer that I have no idea how the 77 film is supposed to look. But these seem to fall somewhere between the GOUT correction and the Blu-ray as-is. 

Here are three more frames from the bluray that have been matched to the Technicolor IB print:

This example of a sequence on Tatooine shows the power of the color transfer method I developed. First I calibrated the color transfer model on a frame from to bluray matched to the Technicolor IB print reference:

Next I used the color transfer model to correct the following sequence of frames from the bluray:

The results are...

The results are extremely close to the actual Technicolor IB print references. 

Notice, how there is a blue cast/blue patches on everything in the bluray: the sandcrawler, the walls of the homestead, Luke's shirt, etc. It's awful!

Great job, i really like these colours. One thing i dislike about the blu-ray is how artificial it looks because of the sharpening added, after checking the Legacy project it proves that Star Wars always had a softer look.

Here's the same sequence of frames, now color matched directly to a reference:

You mean the second set is using the specific IB frame to match, while the first did several matches based on a single frame comparison, right?

The second set looks more natural. The darker regions don't have the weird green blobs going on. The sky is quite white, and it looks a bit strange against the very light desert landscape. But would you say that's how the reference prints looked? Do you think the luminescence is correct? Is the bluer sky in the frame 1 of the first set due to the reference frame used (i.e., leftover blue from the BR)?

Here is a set of comparisons from the two sets:

http://screenshotcomparison.com/comparison/142387/picture:0

Could you post some shots of the binary sunset?, it would be interesting to see how that turns out.

NeverarGreat said:

I think this method will be the way to go when doing color corrections of the Blu-ray, as it automates what would be (and was) hours and hours of work trying to rescue these shots using manual color correction. There will still be problems with the Blu-ray that need to be corrected by hand of course, such as R2's dome in the above shot, which is oddly green with purple panels. That's just the nature of the blu-ray, that some shots are missing color channels and gradients and nothing can be done to fix that without pulling in color information from another source.

 I agree. I mean, it will still be hours of work. And many, many, many hours of rendering time. But, assuming the references are correct (and Mike Verta will someday post his own collection of every shot which the majority of us here will have some faith in), it takes all the horrible second-guessing (and third, fourth, nth) you have to do when adjusting color manually. 

Kingherb said:

Could you post some shots of the binary sunset?, it would be interesting to see how that turns out.

 Me too. 

Also, what happens to the green lightsaber on the millenium falcon? Obviously, it's a different rotoscoped element in there and it's not a shot a preservation would use as-is. Just curious, but I'd also like to see how the rest of the frame looks corrected. 

NeverarGreat said:

DrDre said:

 Those last frames look spectacular!

I think this method will be the way to go when doing color corrections of the Blu-ray, as it automates what would be (and was) hours and hours of work trying to rescue these shots using manual color correction. There will still be problems with the Blu-ray that need to be corrected by hand of course, such as R2's dome in the above shot, which is oddly green with purple panels. That's just the nature of the blu-ray, that some shots are missing color channels and gradients and nothing can be done to fix that without pulling in color information from another source.

Actually, the purple panels were due to inaccurate cropping, before color correcting. R2's dome is actually slightly green tinted from the dirt on his dome. Here is the correct one:

towne32 said:

You mean the second set is using the specific IB frame to match, while the first did several matches based on a single frame comparison, right?

The second set looks more natural. The darker regions don't have the weird green blobs going on. The sky is quite white, and it looks a bit strange against the very light desert landscape. But would you say that's how the reference prints looked? Do you think the luminescence is correct? Is the bluer sky in the frame 1 of the first set due to the reference frame used (i.e., leftover blue from the BR)?

Here is a set of comparisons from the two sets:

http://screenshotcomparison.com/comparison/142387/picture:0

The Tatooine scenes are indeed bright on the reference print. The difference in the first set is probably due to a slightly different color gradings on the bluray. 

The binary sunset and the green lightsaber have been digitally manipulated, and are therefore very difficult to correct with an algorithm. Here's another frame that I love. Peter Cushing was such a great villian. It's a subtle difference, but I think the original is so much better.

Before:

After:

What about this great shot of the greatest villain of all time.

Before:

After:

Looks great.

How do the shots of 3PO and R2 first arriving on Tatooine look?

towne32 said:

Looks great.

How do the shots of 3PO and R2 first arriving on Tatooine look?

 Like this :-).

Before:

After:

Hmm, definitely some weird magenta artifacts going on around the horizon. 

Where'd the other shot go? :)

towne32 said:

Hmm, definitely some weird magenta artifacts going on around the horizon. 

Where'd the other shot go? :)

The magenta artifacts are also in the bluray, to a certain extend. The bluray is really full of weird color artifacts. Blue smears, yellow smears, etc. I will check the cropping, because that can sometimes cause problems, as was evident from before. The greenish discoloration at the edges are also visible in the print, interestingly enough.