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DrDre

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Join date
16-Mar-2015
Last activity
7-May-2024
Posts
3,985

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Post
#792227
Topic
Color matching and prediction: color correction tool v1.3 released!
Time

Here are a few more comparisons between the automated color correction, and the bluray matched to the Tech IB print:

Team Negative1 LPP scan:

Tech IB:

Team Negative1 LPP automated color correction:

Team Negative1 LPP scan:

Tech IB:

Team Negative1 LPP automated color correction:

Team Negative1 LPP scan:

Tech IB:

Team Negative1 LPP automated color correction:

Team Negative1 LPP scan:

Tech IB:

Team Negative1 LPP automated color correction:

Considering how close these predictions are to the Tech IB colors, while not having been matched to the Tech IB, my conclusion is that the original LPP colors were very close to the Tech IB colors. Consequently, I can only conclude that the Tech IB print is very representative of what people saw in the theatre in 1977. 

So, unless the agreement is a huge coincidence, which I think is higly unlikely, I think this is the first solid evidence of what the actual colors were of Star Wars back in 1977, when it was first released. 

Post
#792225
Topic
Color matching and prediction: color correction tool v1.3 released!
Time

So, how do these color corrections compare to the bluray matched to the Tech IB print colors?

Tech IB:

Team Negative1 LPP automated color correction:

Tech IB:

Team Negative1 LPP automated color correction:

The predicted colors are a close match to the Tech IB colors, which includes the slight green shift in the second frame. This seems like too much of a coincidence, so it appears the green shift was also present originally in other prints of Star Wars, and is probably part of the original color grading of the film.

Post
#792209
Topic
Color matching and prediction: color correction tool v1.3 released!
Time

thorr said:

Thanks for reposting 1.2 DrDre.  It's really awesome and fun to use!

Back to my previous question with Bruce Willis and using a different frame that doesn't line up properly, how did you use multiple different parts of the frame to build the color correction model?  With the tool, I could grab a small piece of skin or something white, etc. but I am not sure if that is the right approach.  Thanks!

 You can grab parts of the frame that are very similar, but it won't work if the part is too small or doesn't have enough color information. In principle the method needs to identical frames, with some flexibility, but not too much.

Post
#792192
Topic
Color matching and prediction: color correction tool v1.3 released!
Time

FrankT said:

Is it able to remove the blue tint of Hoth from the DVDs?

 In principle it is meant for correcting old prints, not new color gradings, but it does neutralize the colors if you apply it to a single frame. Normally you would first calibrate the the model on a number of frames of the reel of a faded print. However, here's what it does with Semi-Specialised 2.2:

Post
#792079
Topic
Color matching and prediction: color correction tool v1.3 released!
Time

AntcuFaalb said:

DrDre said:

I've developed a new method, called parameter free color correction

That's awesome, Dre! How does it work? Can you try it with our 16mm SotS scan?

Also, I'll make sure to try the LUT tonight. I had an unexpectedly-busy weekend.

 It's actually pretty simple. You first go to the appropriate color space for film, namely magenta, yellow, and cyan. You then reverse the color order, take the log10, and shift the average colors, and standard deviation to an appropriate value defined by a set of frames of the shifted print. 

Sure, just post a few frames, and then we'll see what we get.

Post
#792071
Topic
Color matching and prediction: color correction tool v1.3 released!
Time

I've developed a new method, called parameter free color correction, for correcting color shifted prints. It in principle has no parameters, and corrects the color with the push of a button. The only variable is a slight contrast adjustment if it is desired, but it works without contrast enhancement. It's also extremely fast. It's done in less than a second. Here are some results for Team Negative1's reel 1 preview:

Just to make this clear. These colors were reconstructed, without any prior knowledge of what the colors should be. 

Post
#792064
Topic
Raiders of the Lost Ark - 35 mm regrade (a WIP)
Time

Beber said:

Definitely looks better than the 1st clip. Especially in the dark shots. Have you consider using Chewtobacca's Blu-ray based on Wowow broadcast and another HD broadcast to get rid of Wowow subtitle and logo instead of the official Blu-ray? Or maybe both of them, to have the best of the 2, as the official Blu-ray digitally switched on a lightbulb in the end and, if I remember correctly, zoomed in some shots in the submarine hangar. And on top of that, the official Blu-ray has a weird "waving lines" effect, maybe a side effect of optical effects, I don't know, as in the very beginning, on the mountain shot at the bottom of the frame, and on a few occasions later in the movie.

 I did consider it (and tried it), but the bluray color timing, although too orange, is closer to the 35 mm references, it therfore much easier to regrade than the WOWOW. So, since the WOWOW would require a shot by shot color regrade, I decided to stick with the bluray, despite some of the changes. 

Post
#792055
Topic
Color matching and prediction: color correction tool v1.3 released!
Time

FrankT said:

Swazzy said:

Open the test image, then x out of the window that pops up. Open the reference image, and x out of the preview window again. Then building a model will become an option.

 Huh, the instructions didn't mention that. But it works now, so thanks! I'll be back with some of my results.

 I've updated the instructions. 

Post
#792047
Topic
Color matching and prediction: color correction tool v1.3 released!
Time

FrankT said:

I'm getting frustrated - I can't get this tool to operate properly! I've imported the test and reference images, but the "build colour correction model" button doesn't light up. I think I might be doing something wrong. Can you help?

 The tool expects you to correctly crop the test frame, and reference frame. You don't have to, but in that case you have to close the figure window before being able to continue. 

I will make v1.2 available again, because I'm still waiting for some feedback on the LUTs I created.

Link for download: http://we.tl/CKTV8zX6cf (available till the 12th of October) 

Post
#791698
Topic
Color matching and prediction: color correction tool v1.3 released!
Time

brycebayer said:

DrDre said:

thorr said:

I think you nailed it!  How does it look when applying to other scenes?

Also, can you repost the tool.  I went to download it but it is expired.  Thanks!

 It looks oke, but the colors in the bluray are very inconsistent, so each shot definitely needs separate regrading. 

I'm nearly done with v1.3 of the tool. It should be up by tomorrow, and will allow you to export a LUT for use in programs like Nuke and Resolve. 

 Nice!  How are you making the LUTs?  In MathLab?

 Yes, I wrote a script to make the LUTs in MATLAB. I do have to test if they work properly.

Post
#791610
Topic
Color matching and prediction: color correction tool v1.3 released!
Time

thorr said:

The clip looks amazing to me.  Is it perfect?  Maybe not, but it is damn close!

I was wondering about something else.  If you have a publicity still that is a different shot than any frame in the movie but it is in the same place and time, can you still use it to fix the color (similar to the publicity shot you recently showed with the guy who gets choked)?  Also, a lot of scenes these days look like they were shot in a bottle of Windex (not talking about Star Wars).  Can this fix that problem if you have a publicity still that isn't doused in Windex?

This is an example of Windex: http://www.dvdtalk.com/reviews/images/reviews/197/full/1371158749_1.png

 It can be done. You just need to find a suitable reference. For this example I used this reference:

As for the Star Wars frame, I first did a reverse color correction. Rather than keep fiddling on the colors, I take a reference whose colors I like, and then adjust the reference colors to match the frame I want to correct. Build a color correction model to reverse the process, and use that to correct the frame.

Before:

After:

Post
#791600
Topic
Color matching and prediction: color correction tool v1.3 released!
Time

Harmy said:

It really seems to need shot by shot unfortunately - look at the pink lights in the first shot for example - the BD is full of horrible stuff like that.

 Yes, and Vader turns somewhat blue at some point.The bluray really is a mess, but at least the regrade is a better startimg point for a final grade.