Color correcting explosion... help!

Hawk Teflon

Hawk Teflon

Veteran
I've been working on a short action sequence, and in a scene, a small chapel blows up (just explosions through windows, really) ... I used Kramers Action Essentials 2 for the explosions, dust, glass, smoke, etc. However, it just doesn't look real. I can't figure out what it is. Is it the color correcting? Is it the compositing? Blah! I need fresh and experienced eyes to look at this short clip. Please help:

http://www.youtube.com/watch?v=8xfPeX_mjEY
 
Some quick feedback for ya:
- The edges of the flames are too distinct and are premultiplied against black. Try some black smoke behind the flames and then put the flames in Add mode (assuming After Effects here).
- There's no glass debris in front of the flames, this is a critical element given your live plate having windows. The boards of the front door help, but those could use some blurring.
- The background plate could use more faked interactive lighting, especially on the front door explosion (where the car and road need to illuminate significantly). These huge gouts of flame must illuminate their environment to sell visually. If you have this already, it's too subtle and the compression of the movie is obscuring the effect.
- Are these multiple charges going off or one uber-bomb/demon/black metal band? The sequencing of the flames from window to window feels pretty slow.
- Kramer often uses a fake camera-shake effect to help sell explosions in his tutorials...it's nice but can get old. Try it, but not until you address some of the more baseline issues. Camera shake should be used for emotional impact, not to fix compositing woes.

Did you see this VFX breakdown Kramer did to promote his Action Pack? It might help you, if you haven't:
http://www.videocopilot.net/products/action2/tutorials/compositing_breakdown/
 
Wow! Thank you so much! I love the details you have!

- I'll try to get some more smoke in there. I couldn't find one I loved, but I may find one I like.
- I put the glass in there, but I think it's so small that you can't even tell. I'll look for a bigger set of glass.
- I have a glow mask on the front and sides, but I'll bring up the intensity on that, too.
- It's just one charge. Should all the windows explode at the same time?
- Yeah, I wanted to get everything done right BEFORE adding camera shake. I've used CS to cover up some boo boos before, but I wanted to get this one right.

Thanks for that link. I wish he went into the flash layers in that short video. I think that really sells it. I would imagine an orange layer with a glow? I'm not sure.

Again, thank you! I'll get back to work now!
 
few more suggestions.

1. this seems like its slow motion. i would speed up the first 3/4 of the explosions to about 300-400 % so that the fireballs blow out very quickly , and then ramp down to those nice flames licking upwards after a short blast.

2. yes, i would blow out all windows at once.

3. speed smoke up in the same manner, but bring into comp about 1/2 way through the fireball so that smoke comes from the fireball.. not with it. .. because you DO get smoke from fire. but.. as is evident in that statement, it comes FROM fire.. not with it simultaneously in an explosion. the fire should come first, and then be quickly overshadowed by the smoke. what you want to come with the fire.. and even a little before it in alot of cases is the DUST and DEBRIS. since the concussion force would blow that lighter material out first before the fire can come through. then of course its nice to have it linger or still falling after the initial blast, as it would hang in the air for a while. often these touches are what really sell the effect. as atomick says .. add the glass blowing out, and i would add other debris and dust right with that glass. again.. time it to match the fireball so that its more of a sudden blast at first. than a spurt of kerosene on a flame.

3. you are right. do your full composite.. and THEN add camera shake. trying to correctly track and composite a shaky blurry image is not a good idea if thers no reason to do so.

4.instead of using glow for a illumination , try just bringing the levels up on the mask surrounding the blast to increase brightness ..try using HSL or levels. . if you fade the mask nicely your effect will be more intense closer to the blast and will fade off as it gets further away.

5. vary the size and intensity of the blast from different windows on the side. even though the windows are the same size. the blast should effect them differently. if you have a differnent side blast try using that for the fire. opr perhaps only have fire come out of a couple, and one just gets the concussion and tosses alot of debris and glass out. .. for the one or two with fire, mixing it with seperate debris and dust ect. will help randomize the appearance. and make it appear more naturalistic.

6. if you blow all church at same time. remember to blow front door as well in first shot, and then you can just cut to front door only shot halfway through the explosion. to continue the blast from that view. this will also help sell the shot since people cannot concentrate on the blast from the side windows or front as long, and do not have time to study the effect in action . you want it to be sudden and shocking, and over with before people can sit there and pick apart anything that doesnt look right. this is why the camera shake helps as well., but dont overdo that if you want people to pay attention to the coolness of the explosion, rather than the psychological effect of it. ..in other words. if you want a neat effects shot, and thats the point of the shot, then let them see it clearer, ..still speed it up, just dont shake too much so its ll jumbled up. .. but if you want the psychological effect of what the explosion means to the story/charachters to have precidence, then you can shake and let it jumble in a more realistic violent fashion, because they should be thinking about what that explosion means.. not concentrating on how cool it looks. ..anyway hope im making sense here.


like to see what you do with it from here :)
 
Uh, what Neil said. :)

Another classic trick is to avoid glows and instead duplicate the live plate, mask it where you want the interactive lighting/blast flash to happen, put it into Add mode, maybe radically increasing its contrast. That way the shadows still stay dark but the other stuff really heats up. You control the blend not only through opacity but the contrast adjustment; you can also use the Tint effect to warm it up.

Post revisions, and good luck!
 
edit looks better. more like and explosion instead of flames coming out of building. you could cut to the front shot a little later, and actually replay from the same edit point of front shot since wevee already seen the major blast, and then we would cut to billowing fire out the front at a slower speed. this would make it last a hair longer overall to take in, and let us see a little more (1/3 or 1/4 second) of the first blast.

however, i dont see any of the effects changes yet. just a change in speed ramping and edit point. which does look much better, but doesnt sell the effect by itself. the other things like debris and dust and smoke and varied explosions ect. ..all those other effects and compositing tricks in action are what will really sell the effect.
 
Ok ok, so you're saying add debris to the windows as well? I tried making the glass more visible, but in the compression, it lost everything. I'll try that tonight.

For some reason the dust isn't showing up from the windows either. I'll crank the alphas on that one, too.

I'll work on this more tonight. Thank you!
 
yeah. i really cant see that stuff there at all. and if your using h.264 it should show up fine. its the same compression as a blue ray so it should be able to show anything you want people to see in teh final product :)
 
I don't have that youtube account saved on this computer. I'll have to upload it later today. I think it's looking better, though.
 
I know they say not to use camera shake to fix compositing woes, but I feel like that's not what's happening here. Watching that big of an explosion, and not seeing any movement in the camera, no lines, no distortion, no rattle or bump... seems very unrealistic to me.

Add a camera shake, and fix your edit. Your cut from that first clip is still WAY too soon... we can't even get a good grasp on what's happening before we are forced to watch the front door.
 
Getting there, Dr. Telfon. Some more thoughts for you:

- Think about what the ambient light and fire would do to the debris. It's bright out there, midday sunlight. Would it REALLY be that dark?
- That huge explosion is still not interacting with the scene because the nearby objects - lawn, trees, car, asphalt - aren't being briefly and intensely illuminated.
- If this is a fireball, some portion of something inside will catch fire, and the explosion will cause air to rush forward out the windows. This suggests that black, billowing smoke should follow the explosion and continue. Maybe not a lot at first, but certainly some. Just because the explosion explicitly ends doesn't mean the scene doesn't go on with smouldering and other mayhem.
- I agree with Kyle that this scene could benefit from SOME camera shake, but I still strongly feel that you shouldn't add that until the shot feels resolved in all other ways.
- Kyle's also right about the cut. Too soon. Realistic, maybe, but not as dramatic!
- Fire isn't dark. It doesn't have dark parts. And this is bright daylight. Be careful how dark you take the color of the flames. If you want them to pop more, consider a cooler color grading treatment to the original footage - go subtle, mind you - so that the flames and interactive lighting I keep harpin' on punches nicely. Just a thought, but tread cautiously, because if this is part of a larger sequence that kind of color grading has editing and narrative implications...

Finally, realize you can tweak this s*** forever. Only you can determine when it's time to stop twiddling and move on, and that's based on your interest, experience, and attention. I mention this only so that the continued feedback is taken as it's intended and that you don't get deflated over the remaining suggestions. If you have time, though, I say keep plugging away!
 
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