MPC Dossier: tips for photorealism

Whether you’re developing the highly stylized world of Dickensian England like the Blaine Brothers, or more mundane scenes that the audience don’t know are there, there’s a lot we can learn from how real photographic imagery is constructed.

Ian Murphy, Senior Film Compositor and Training Lead at MPC, offers some top tips to make your shots more convincing and help sell your VFX as real. These are the kind of things MPC look out for to try to make their comps *“photoreal”.

Making Composites more convincing

• Examine the plate and carefully look at what’s in focus and what isn’t. Match the focus and depth of field to any element you are adding.

• Gaussian blur is a particular popular filter that you’ll find in VFX software. Avoid using gaussian blurs to simulate an ‘out of focus’ effect, if you can. The pixel averaging method of a Gaussian blur will tend to flatten your image’s highlights too much.

• Take up photography! Having a good understanding of lenses, exposure and depth of field really helps. At MPC we regularly run practical lens and camera workshops for both compositors and animators. They’ll never need to take pictures, but the more they know about how types of camera can subtly alter the image, the better their work is.

• Try to make sure that the darkest shadow/black levels and the whitest highlights in any element you add are the same as the background plate. You can check this by taking the Expose/gain/brightness or gamma up on the entire image to check that the blacks are matched, or down to check your highlights.

• Avoid ‘choking your matte’ (alpha channel). It’s tempting to shrink your matte a little whilst keying to get rid of problematic edges or nasty ‘spill’. It’s better to solve this with careful colour manipulation or ‘despill’ on the edges.

• Don’t use blend modes like Add or Screen all the time uncritically for adding things like smoke, (or steam or mist). Think about light interaction in the plate and the story (is this magic smoke or nasty thick oil smoke?). It often works better to re-time smoke (slow it down or speed it up). Also take the smoke, scale, flip it, and soften its edges and use it as a matte rather than an image. It’s often the case that we work with two or more smoke layers to give smoke or dust some volume. The first layer is solid colour through a matte then a second layer adds highlights through luma key or subtle additive layering. Often it’s about showing a hint of smoke/dust, in which case the layer opacity control is your best option.

• Think about how cameras show us the world. For instance, if you put a very bright object into a photo that was very dark, the bright object will ‘blow out’ – we lose details in the brighter areas. Conversely, if you were to expose your camera to see detail in the bright object, you won’t see any detail in the background – it’ll look too dark. So, your images will look more realistic if you can mimic this kind of camera property in your work. But don’t overdo it. Trust your eyes!

Do share your tips and tricks of how you’ve made composited images seem ‘photoreal’ and natural, fooling the viewer with tricks of light or camera.