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Techniques and ways of fixing Black Crush or Crushed Blacks

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This is something that is interesting and I am surprised there is no topic or at least not one that I know about and this happens in a few films where shadow details are lost and crushed in to nothing.

I am curious of ways of attempting to fix this problem using various techniques.

Upon looking at Empire strikes back for a long time. I wondered about this and without actually doing any tests. I am assuming that 2 sources could be mixed either 50/50 or 75/25 and color matched to retain shadow detail.

But then I started to think about it differently again. all you want is the bottom end in this case or perhaps if you have the other end of the spectrum blown highlights you would want to only replace highlights from another source and mix. without altering the image in the bottom or middle range.

Now obviously we can match and blend 2 images 50/50 and 25/75 as whole images for instance, but after thinking about this some more I realized the middle of the image is generally the part that is good most of the time when looking at value.

So I want to talk about developing a technique that allows for not mixing an image as a whole in any percentage but mixing an image as either top end complete replacement but geometrically matched, or bottom end replacement but geometrically matched.

Basically my thoughts are on how to develop this technique lie within a few different areas.

Assuming what you want to replace is actually black or white and without any detail. would a bucket fill technique work to chroma key out the black crush or blown highlights? Splitting a clip to individual frames and simply bucket fill the lot with either red / green / blue screen and then keying out replacing the affected areas with the alternate source without crushed black or blown whites.

obviously this could be matted in but without having to get into complex roto-scoping in some instances even if a selected area is colored and then keyed out to reveal underneath it shadow detail from an alternate source or highlights that are not blown from another source.

once what is keyed in to reveal a geometrically matched source underneath either restoring highlights or shadow detail then if detail is also lost in this process then another layer is added of the original source you want to use but opaque to a percentage where detail is restored again? or masked in, and in such a way that it is geometrically common sense around the affected areas of either Black crush or Blown Highlights but this would be a simple mask without having to do precise rotoscope work.

Without testing this does anyone have any thoughts or has anyone ever attempted to restore these types of things before and what technique if you are willing to share did you use to restore detail?

This is all theory at the moment. But aside from simply masking in shadow detail I want to develop a technique that if there is any movie with either Blown Highlights or Crushed Blacks a simple resource that can fix it or tutorial or technique providing another source even if it is in lower quality can yield better results and restore either shadow detail or blown out whites.

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I wish the black crush in the nightmare on elm street blu ray box set was fixed and whatever else maybe wrong with the set same goes for ghostbusters one maybe two don’t know about two. Also if you can’t fix the things adywan missed on his edit of empire could you ask someone else if they could do it? please reply to both.

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Right this was the process I used on my first attempt. And I used Luma Key. (it will be a different process for blown highlights)

First off looking at the original source with crushed blacks the Empire Strikes Back Blu-Ray not sure if this is the best example as sometimes elements get moved around. anyway make 3 video tracks and put this on track 2.

Now we take the alternate source that has the shadow detail present this goes on track 1.

We lay this on top of the image that we want to combine but in order to line the 2 images up we need to first make the image with the shadow detail opaque. We Add a 2D-DVE to this Re-size and scale as needed and lay over the top so that if possible it matches exactly using the highlights as a guide and matching the geometry of the 2 images. (If I have a slightly different frame or something I apologize but for the purposes of explaining how to do this as I don’t have much time today due to other comittments). I sharpened the source with shadow detail as it was a lot more blurred than the source I was trying to blend.

Now once we have the 2 images matched we move the image or clip with the shadow detail on to track 3 keeping the geometry matches but now you must make the image or clip have 0% opacity so it is now solid.

We now go back to the image or clip that has shadow detail missing.

Here we apply a Luma Key to the image or clip. Generally for shadow detail you will have a high tolerance and little edge softness. Here was the result.

Now you have shadow detail the image will then need to be matched to the rest of your footage so contrast and color so on and cropping or masking around the affected area with no shadow detail.

If you want me to try this on ghostbusters or nightmare on elm street then it would be beneficial to show me the shots or comparison sources to restore shadow.

I won’t be touching Adywans edit but I think it’s useful for everyone to try to deal with this problem because it’s not unique to any film but a plethora of titles. And I need to try this technique on other sources.

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starkiller base said:

i don’t know how to add images

put your images on a image hosting site… then type what is inside the speech marks without any spaces replacing URL within brackets with your copied URL for the image “! [ ] (URL)”

If you can post the same frame or very nearly the same frame… I did not want to have to rip another source just to demonstrate this technique so I screen grabbed from a DVD I think I might have been a frame out…Or my line up was a bit out. The Line up is the hardest part especially when the framing is so, so different.

There was a good reason to use that still from revisited because it proves that the Middle and top are unaffected more or less by the Luma key. And the added asteroids are still present although they are dimmed because there was nothing there in the other source.

After playing with the Luma Key some more I found edge softness 33.79& and very little tolerance around 96% yield better results. But this is the first time I have tried this so it’s all a bit of learn as you go. The line up really is the hardest part as I said before. I unsharpened the other source also as it was far too sharp. So please post what ever you want to for further tests.

What I am discovering though the software I am using is not precise enough in incremental scale to match geometry of the 2 shots as I only am able to scale in hole set increments and not percentages so I will never be able to match the size and scale with the software I have on this still image But with that said the 2 shots were very different in terms of the scale and positioning which is not entirely normal to have such different framing. basically my x scale needs to be in between 96 and 97 I think, and this is something impossible using the software I have. Or something has been done to extend the Star Destroyer at the far left because the lights don’t match so it’s either my software of the super stardestroyer has been digitally extended or elongated?

What is also interesting is if you keep the extra bit on the left from the Special edition / blu ray and the extra bit on the right from the theatrical it is quite nice too. And it might bee the correct aspect then but there is something at play here… Not sure what.

One more example and I think this proves that it will or does work in undoing black crush. Although I do think I have a slightly difficult task with the software I am using as I can only position with the mouse and I can’t nudge the image in any sort of direction without having to wobble it about left clicking. So yeah my software is not precision enough. But this is not the purpose of thread because It’s more about the technique of doing but the software I have it’s too difficult to position and scale effectively. But this process would work 100% providing you can scale and position much more precisely than my software can (Lightworks).

Luma Keyed in

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I can see the black crush in the ghostbusters image yeah it’s well bad…

But I think you are putting the wrong URL or something. You know do you have an image that does not say preview also across it? or can you link to the clip on you tube even?

I have Ghostbusters on DVD and could use that to test on this. I also have R1 nightmare on elm street box set so I could also potentially test that too. If you post an image from the source that has crushed blacks i.e. the Blu Ray and a screen grab. But like I said the software I am using is quite limited on the geometry front.

Also give me an idea of when in the film it is. But I am pretty familiar with Ghostbusters more for NOES

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just link me to the clip on youtube and I will screen cap it. like movie clips or something.

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with nightmare on elm street box set i don’t know how many films in the original series have black crush. i don’t know if 1 or new nightmare have black crush but it looks like throughout 2-6 do. i look up caps from 2-6 and it looks like every cap on caps-a-holic.com has black crush making the colors look wrong and other issues maybe too. it also doesn’t help the sequels aren’t on separate discs this is why i don’t want to get the blu rays. also one other minor grip 1 5 6 aren’t uncut.

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i want nightmare on elm street 2-6 in hd so bad but the black crush is awful

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http://www.ghostbustersnews.com/wp-content/uploads/2013/05/bluray_comparison_05.jpg

I used these 2 stills to mix the Luma of the 2009 Blu ray and the 4k master.

It does not happen in the blink of an eye… I have to do stuff to it…

so that is why you see both text underneath the image. It is fixable absolutely I boosted the bottom end a bit for the 2009 but there is detail there to boost.

This was a 50/50 Luma mix

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Nightmare on elm street 4 does look bad in the darker shots on capsaholic so with what I am talking about mixing Luma to get rid or black crush the main problem is you would have to conform the sources framing wise and these seem quite different looking at the Junkyard on Capsaholic and the girl in the room with the bike the DVD chops off the top of her head the Blu Ray is better framed but unless there is a source that has the shadow detail and in a similar framing to the Blu-ray then yes it is possible but like I said framing is an issue. But with all the versions of Star Wars and prints and alike it’s not really a problem per say to match the framing so much. In this instance it is a hurdle. (Not that my software can do it very well either!)

Ghostbusters does not seem to be a problem as the framing of the 2009 and new 4K master are pretty much the same and would probably just say get the 2009 Blu-ray potentially on that one. As it does not seem to suffer.

Nightmare on Elm Street 4 is potentially more obscure but if a source exists in the same framing without black crush yes it’s absolutely possible but even if you tried to conform the Blu-Ray to the DVD for NOES 4 you would potentially find more image at the top on Blu and more image at the bottom on DVD so it is a tricky one due to the framing and obscurity and lack of different releases.

Basically you can’t get the detail and the Luma as a whole unless a different release has a framing similar to the Blu ray on this one.

Potentially with the 4K ghostbusters Blu ray it has much more darker color information but your TV might be incapable of displaying it. This is a distinct possibility as mine won’t display HDR or anything… I have a normal old HD LCD monitor still.

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the framing of DVD and Bluray of NOES 4 are totally different. Is there a release that has the same framing as the Blu-ray i.e. the same or more amount of picture as the Blu-ray?

Ghostbusters 4k - UHD >> do you have the actual release and are you watching it on a UHD TV? And if so does it look like the capsaholic pictures on your TV?

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The only option to fix it would be to obtain a print of the film and scan it and from there you could mix or just have the print digitized to watch. This is the big pitfall in this technique but it all comes down to framing or having a match of the complete image or complete affected area of black crush as you can mask in on selected areas too. But you could potentially cheat a bit but in NOES 4 perhaps a 4:3 release could do some of the donkey work and then you might be able to crop in from that a widescreen image but it is quite different framing by the looks of it totally different amounts of the frame.

Try to find a TV Version for NOES 4

so it’s not a UHD release ghostbusters?

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no there is a uhd blu ray of ghostbusters but i have the mastered in 4k ghostbusters blu ray

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Then it is crushed Blacks go with the 2009 Blu-ray…

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