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Keylight
Adobe has announced that The Foundry's Keylight will be bundled with the upcoming release of After Effects 6.0 Professional Edition. Amongst VFX professionals Keylight is no stranger. From the manual: "Keylight is an Academy award winning blue and greenscreen keyer. The core algorithm was developed by the Computer Film Company and has been developed and ported to After Effects by The Foundry". Keylight has been available for a couple of high-end compositing solutions for a while, from Shake to AVID|DS upwards to Flame* and Inferno*, with prices ranging from $1250 to $7,500. The Foundry is well known in the industry for other high-quality plugins like the Tinderbox series that are also available for After Effects. At this years NAB The Foundry premiered the port of Keylight to Adobe After Effects. At that point in time Keylight for AE was still in beta and the Foundry states that in fact the After Effects version of Keylight is a further developed algorithm and effectively a 2.0 version (although the software information will state 1.0). After installation of Keylight which comes with it's own installer, the plugin can be found in the Keying menu of After Effects 6.0 Professional Edition. After doing some quick tests that looked promising I thought it would be fun to revisit the footage that I used when I wrote my first article for Creative COW about chromakeying difficult footage. It was shot on DV under pretty bad circumstances. Preparation of the footage Without making this a full-blown tutorial, I'll quickly explain the preparations I take before keying DV footage. Without these preparations no DV key is going to good good anyway. I usually prepare my footage by de-interlacing and de-artifacting using Magic Bullet. Especially the de-artifactor does an excellent job at removing the pixelation of especially the red and blue channel that are the result of the 4.1.1 (NTSC) or 4.2.0 (PAL) color space of DV. There are examples of the de-artifactor in my review of Magic Bullet. If you don't have Magic Bullet, try this: Add an adjustment layer on top of your footage and apply a gaussian blur of around 4 pixels. Set the transfer mode of the adjustment layer to [Color]. This way you slightly blur the colors without touching the luminance, so the image is perceived as sharp, but some of the DV artifacts are removed. Precompose the two layers and apply the keying to the precomposed layer. It doesn't work as well as the Magic Bullet de-artifactor, but if you're on a budget, this will at least help. A quick and dirty key Like I said I took and old clip from my original chromakeying tutorial to see how Keylight could make life less miserable. When all the parameters of Keylight are folded out there's about 45 parameters to tweak... (If you want to see the whole bunch, click here). Now don't be frightened away by this, the most essential tools are arranged right in the top, and depending on the complexity of the key you'll gradually work your way down until you're satisfied (uhm... that didn't come out right...). The default screen color of Keylight is black, which doesn't do anything. A trivial but nice touch - in many other keyers that default to green, you need to disable the effect, select the screen color with the color picker and then enable the effect again. After selecting the right screen color I instantly got a half-decent result. Well, better than I had ever had using this particular footage.All the background is keyed out without serious holes in the matte. With better shot footage, preferably less compressed and less noisy, chances are that picking the right screen color will do 90% of the work.
Well, as said the first result looked somewhat decent in it's own right, but the matte is too soft and a quick look at the resulting alpha channel shows that the screen needs cleaning up and the density of the matte needs some work to get the holes out. So let's take a look at some of the other tools Keylight has to offer. First of all Keylight offers a set of different view of the results in different stages of the process. A particularly handy view is 'status' which renders an exaggerated view of the matte. With this view enabled, it's easy to adjust the Screen Strength to the right level: until all the background is solid black, without eating too much into the foreground matte. Next I tweaked the Screen Bias a little to lift the density of the matte a little, reducing the holes in the foreground. The resulting matte looks a lot better, and this within a minute or two!
Well, this article was supposed to be a sneak peak so I'm going to pick up the pace a little: the basic keyer in Keylight serves as a spill-remover at the same time, and using the Despill Bias control the amount of spill removal can be tweaked. Advanced keying The next set of tools is for tweaking the matte, with it's own Clip Black and Clip White tools, Grow/Shrink and Spot Removal, serving the purpose of refining or smoothing out the matte if it doesn't look right yet - somewhat resembling After Effects own Matte Choker in it's goal. This is where you can tweak the details of the matte to remove the specks and lift the density to make a nice solid matte. Here you can also control whether you want to blend a little color back into the semi-transparent areas, if the spill-removal results in unwanted loss of color. Color correction Built into Keylight you'll find a very usable set of basic color correction tools, and separate color correction for the edges of the foreground. The basic tools are Saturation, Contrast and Brightness, but you'll also find Color Suppression, Suppression Bias, Suppression Amount and a nice Color Balance Wheel. The width and softness of the reach of the Edge Color Correction can be manually adjusted.
Conclusion Well, I must say I'm impressed. This is a very, very complete set of tools, added to a very powerful keying algorithm. Besides the keyer you get matte tools, color correction with separate controls for edge color correction, inner and outer mask tools... the works. And it works really well. I would have been very happy with the addition of the basic keyer to After Effects, but Keylight is a huge bonus to the After Effects toolset. So, is this the only keyer you'll ever need? Well, no. I tried Keylight on a wide variety of greenscreen and bluescreen shots, and it worked excellent on all the material. But Keylight is a chromakeyer, meaning that it works on the color information. It won't be very effective if you try to use it as a luminosity keyer, so it's always good to have a couple of different tools at hand. The 76 page manual that The Foundry wrote for Keylight deserves a big compliment. It starts out with a quickstart guide which gets you up and running within minutes. The next part explains the basic theory behind the color keyer in very clear language. Then all the tools in the Keylight effect are explained, including why and when you'd need them, with very clear examples - the used images can be downloaded for practice at The Foundry. These same images are used in 20 pages of tutorials in the end of the manual. All in all I find the manual very well written, highly readable and a subtle touch of humour. Well, as you can probably tell I'm sold. I think Keylight is almost worth the price of the upgrade alone. Unless you are sure that you won't find a single composition job on your doormat for a long time, I'd seriously consider upgrading to the Professional Edition of After Effects 6.0. Keylight is bundled with both the full version and the upgrade to Adobe After Effects 6.0 Professional Edition (wow, that's a mouth full...) and will be bundled for the life of AE 6.0. It's not definit yet whether Keylight will be bundled with future versions and upgrades. The Foundry says there are no current plans for selling Keylight separately from After Effects, and there's currently no time in their schedule to work on a stand-alons 2.0 version.
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