Grading Uncontrolled Lighting


Jun 09

After recently completing the work on the second spec Walk MS PSA, “For the Children” I thought a discussion on grading shots in uncontrolled environments was in order.  As a filmmaker, you always want to plan, art direct, and control your compositions, but when you are running and gunning during a live event like Walk MS, you don’t always have the opportunity to stop the action so you can light it or art direct it to your “vision.”

Case in point, the following shot from the PSA featuring a child on his dad’s shoulders. Click on any of the pictures to see it in full 720P resolution.

Piggy Back Kid - As Shot

Not a bad composition, but if I had the time and the crew, I would have loved to have put a reflector in there to brighten up the kid’s and his dad’s face.  I’d also like to get rid of that hand in the bottom left that’s taking the direct sun and becoming a focal point.  While I’m at it, I might have put a sky filter on to enhance the sky which over-exposed a bit.

So, should we let the fact that we didn’t have that time and crew in the moment ruin this shot?  Absolutely not.  Instead we  begin the  post color grading process.  Some people (including myself) call this color correction, but I think that grading is more appropriate as we’re doing a lot more than simply correcting the color.  For those wondering I shot on a Canon EOS 7D using Stu Maschwitz’s picture profile settings from my previous testing.   This flattens the image out giving you more highlight and shadow detail to work with when grading, which came in very helpful here.

I should also mention that I transcoded the original 7D quicktime file to Cineform files.  As I mentioned in my previous post the native Quicktimes are very compressed and have limited color information.  Cineform does a great job at preserving the original image characteristics while converting to a 10 bit 4:2:2 color space which makes it more robust for color grading.

I graded in Adobe After Effects, with Magic Bullet Looks because it works in 32 bit color space and allows me a lot of control.  You can also color correct in your NLE, or dedicated color correction program.   I will be making reference to tools in After Effects, but the principles will be the same no matter what tool you use. When you start to grade a shot you should remember to do things in the order that you would have done them if you shot for the look in camera.  First compose, then light, then add filtration, then apply the look or color timing.  The DV Rebel’s Guide has a whole section dedicated to this and why, I highly recommend you check it out.

So let’s start by doing what I wish I had done on site,  and add a virtual reflector to  brighten up the kids face.  I used Magic Bullet Looks (MBL from here on out)  Spot Exposure tool for this, but you can also use After Effects built in Exposure effect and feathered mask.  Mask  his face with a soft  feather and increase the exposure until it looks correct to you and the kid takes on the focal point of the shot.  Here is my result.

Not bad, but now Dad seems out of place.  Let’s bring his exposure up as well, without taking primary focus off the kid.

Better.  Now let’s deal with that bright hand drawing our attention off screen left.  I approached this the same as their faces, only using a virtual flag to decrease exposure on the hand.  While I’m at it, I also take the exposure down on the kids arm.

Much better. Now that I’ve re-lit the scene, let’s think about that sky.  Since this is a PSA that’s hoping to make you feel good we want a nice clear blue sky instead of the grayish overexposed sky we have here.  Again I  used MBL’s gradient filter to add a blue gradient over the top right corner of the sky.  This makes the sky blue without affecting the rest of the image.  You can also use a blue solid in After Effects with a feathered mask and transfer modes to create similar effect.

Now that I’m happy with the relighting and filtration it’s time to color time the shot to give it  it’s overall look.  As this is a PSA where we wanted to instill hope, I wanted to go for a warm look, so I gave the shot a warm, golden color cast and added a curves effect with a film-like “s” shape for contrast.

This gives it a warm, magic hour feeling.  Also notice how the look altered the blue of the sky, but in a way that’s natural to the rest of the shot.  If I added the blue after the look, it wouldn’t have taken on the golden cast, and would feel disconnected from the rest of the world the shot took place in.

Lastly, I shoot with a picture profile in the 7D that turns the sharpness all the way down.  I do this because out of the box the 7D (and most DSLRs and video cameras) over sharpen the images they shoot.  I don’t like giving my camera that much control. I like to turn that sharpening off or in this case down as much as possible so I can precisely dial in the right amount of sharpening for every shot.  For this particular shot I used After Effects “unsharp mask” filter.

But wait a minute, that looks terrible!  All the artifacts from the original heavily compressed quicktime are accentuated!   (If you can’t tell, click on the image to see the full rez version.) That’s what I said the first time I applied some post sharpening. While Cineform does an excellent job dealing with the color space, it doesn’t do any noise reduction or deartifacting. But don’t be disheartened. Simply go back to your source file and add some noise reduction as the first effect in the chain, or the first layer if you’re using adjustment layers. I used the noise reduction filter that came with Magic Bullet Steady and it did an excellent job. Other choices are Neat Video, or DE:Noise.  If you don’t want to buy a plug-in you can also try After Effects built in Reduce Grain or Median filters, but I couldn’t get the footage as clean as with the plugin, your mileage may vary.

Ah, that’s much better.  And to see the results in a much more dramatic comparison, watch the grading progression video below.

Tags  , , , , , , ,


Related Posts

Leave a Reply

%d bloggers like this: