Friday, 27 January 2012

Karl Bowman Green Screen Shoot

Just before Christmas I had another opportunity to collaborate with the fantastically talented Couture designer Karl Bowman.

 We had two models and six dresses from his new Red Carpet collection to shoot for upcoming magazine feature. The plan was, as with our previous session, to shoot the models again the green screen in my studio and composite in to various backgrounds. The previous set of images had all ended up against contrasting urban environments, mostly taken from stock photographs.

This time I really wanted to try using some big dramatic skies and landscapes as backgrounds to make some striking and (hopefully) very different fashion images.

Big dramatic skies and landscapes I happen to have easy access to...

 I had originally thought that I'd be able to trawl through my back catalogue for unused/not quite finished shots to find some suitable backgrounds.

The first problem I came across using my own "stock" landscapes was that I just don't allow space for adding extra elements when I'm framing a landscape shot. Plenty that were almost right, but not enough sky, or foregrounds that were simply at the wrong angle for the models to stand on. After a few hours of hunting through the lightroom library it became pretty obvious that I was going to better off getting out and hunting images in the real world. I got pretty lucky in the dramatic weather department and had the first few in the bag before the studio shoot was scheduled. The rest presented themselves within a few days of finishing the studio side of things.

Which was just as well, given that I had a total of eight days between the shoot day and the print deadline...

Studio Day:
The studio shoot was a pretty straightforward single day. I'm sure I've still got a lot to learn about green screen shooting, but I'm getting pretty confident about getting the lighting and exposures that work. The big pitfall that I've learned to avoid is not over lighting the green screen. Sure, it needs to have some light thrown at it, and it needs to be fairly even, but it doesn't need a lot of light. The more light you throw at it, the more sickly reflected green spill you'll get catching on the edges of your models. And that's not a good look for anyone.

In a lot of cases, when I'm using a soft fill on my subject enough of it will reach the backdrop to do the job. In the shot in the right I ended up without any dedicated light on the backdrop; the poly boards I use to block glare from the backlight (right of the model) were bouncing plenty of light onto the green. Between that and the front fill we had more than enough.

I've also taken to standing the models on either black or white PVC, rather than on the trailing end of the green screen itself. It adds a little bit time in photoshop, but cuts out the faint green uplight effect of standing the model on the screen.

I've started looking at my on-camera image reviews in black and white, which makes it a whole lot easier to make judgements about light, exposure and contrast when you're not being distracted by the overbearing greenness of it all. Models and clients seem to like it too, I guess partly because people always look good in black and white.

My new toy on this shoot was a big white beauty dish that I was using with a 'showercap' diffuser over the front. Fantastic quality of light, softer than a softbox, perfect catchlights reflected in the eyes. Just all round lovely. I use it in various positions on different shots, on the right you can see it on a boom above and slightly to the right of the model.

Backlight is always a critical part of lighting for a successful chromakey image. You need something to lift the subject off that backdrop. Happily, more often than not, my landscape work involves looking into the light. That's where the texture and drama is found. Even more happily, this means that the easiest style of lighting to work with in the studio, and which creates the easiest images to work with in photoshop, also happens to be the best match my background landscapes. I like when things fit together like that. It makes me feel like it must have been a really good idea to start with.

Planet Photoshop:

My top tip for keying out green screen backdrops is put your image in a layer group, assign a mask to the group and edit the mask to remove the background, rather than erasing bits of the master image. That way, you can always go back and re-edit your edge.. And, added bonus, you can put other layers inside the layer group and they will automatically only be visible within your outline. For example, I add a layer which I then take an airbrush to for retouching. Because that retouching layer is inside the layer group I don't have to worry about strokes that run over the edges of the model; anything outside our outline is automatically hidden by the layer group's mask.

If that last paragraph doesn't make any sense whatsoever (and assuming that this fact bothers you in some way), you'll need to read the full, in depth article on photoshop chromakey techniques that I will, one day, find time to write...

OK, you could argue that the beauty and fashion industries are doing terminal damage to our collective psyches by portraying human beings in an  unattainably perfect light, and in some cases, you'd have a point, but honestly, I'd be very surprised if there was anyone out there who couldn't tell the difference between documentary realism and playing at dressing up. No, the model's skin was actually normal human skin, yes her eyes are actually that colour, and no, ballgowns are not appropriate clothing for winter mountaineering.

Most of the retouching is achieved with a good old fashioned airbrush tool. Sampled colours from the original image and very carefully brushed in to a new layer. I always use a wacom tablet for this bit and set the airbrush's flow to 10-20% to build up the brushwork up very gradually. It's easy to get carried away and end up with a model that looks as though she has been extruded from a single sheet of polyurethane. Less is more is the mantra and the eraser plays an equally important part as the brush. Spots and blemishes tend to get taken out with the clone tool.

Once the model is removed from overbearing greeness of their background, it's just a question of finding them a new place that looks like it could be home. Again, fairly complex subject, but the short version is that matching the angle of view is critical. Everything else, like exposure, noise, white balance, contrast, sharpening can be tweaked. But if the camera was three feet off the floor in the studio and six feet off the floor on location, the model is never going to look like she's in contact with that ground.

The original shot below happened to be one of the few that was already in the library before we started. I had no idea it was going to end up as a background. Karl like the idea of something with arches playing a part in this image, because of the viaduct construction of the dress. Haweswater pump tower is my go-to structure for arches, being such a great structure that is so obviously straight out of a fairytale.

The obvious change is that the image has been flipped to match the direction of the key/back light in the studio shot.

As mentioned earlier that strong backlight that works so well on chromakey shoots for technical reasons, is a great match for how I like to shoot landscapes. Happy days.

A slightly less obvious tweak is that the foreground shoreline has been extended to give our model
a bit more space to stand without obscuring the fairytale tower. This is achieving very simply by copying the whole background, shifting it left and then masking out everything but the rocks. The bottom of the dress covers a whole mess of mismatching rocks.

The final tweaks are mostly edits to colour, levels and contrast. Some adjustments are made just to the model, some to just the background. Others are made to the whole image.

The contrast adjustments in this case involved some odd techniques that involve editing individual colour channels. But that's another complex area that will eventually lead to a whole article of its' own.

One commonly used cheat is to apply a 'photo filter' layer to the whole image. In this case a simulated Wratten 80 cools things down a bit and helps blend the foreground and background colours.

And a bit of gaussian blur applied to the distant background just to give a slightly decreased depth of field to lift the model off the background a little. Odd, having spent so long making her blend it to the background, but odd plays a big part in this whole process...

1 comment:

  1. Wow, it looks amazing . Green screen background kits always best option for experienced Photographers.
    Thanks for sharing your experience.