Using Photoshop and Your Brain to Produce Diorama Illusions

 

Background 1: Understanding the Mind’s Eye

The mind is an interesting construct. I’m sure you have spent some time looking at optical illusions. Why do they work? Why is it that we see some things that aren’t really there?
At the risk of sounding a bit Zen for an image editing tutorial, the answer becomes clear when you remember that you are not actually experiencing reality when you look at the world. Instead, you experience an internal representation of data from your sensors (in this case your eyes).
When you were very young, your brain wrote the software that it uses to process image data from your eyes. The more reference data this software collected, the more solid its view of how things look became, and (importantly for this effect) how those different things appear in varied situations.

Background 2: Effects of Depth of Field on Perception

Your brain developed a fairly simple set of rules that it uses to determine what looks right with regards to size and position. Here are some of them that are pertinent:

1. Objects close to us have higher resolution than objects far away.
2. The object that has your central focus is seen clearer than one that is on the periphery of vision – even if the peripheral object is nearer to your eye.
3. The further away a scene is from you, the flatter it appears and the less detail it contains (comparatively) to close-by objects.
4. Very clearly defined objects are either: very close or very large.

Depth of field is a term that many of you will be familiar with. It describes how far away something can be and remain in focus. You can easily see its effect if you hold your hand flat in front of your eye, so you can see past it. Close an eye, then focus on something across the room and you’ll see that your hand fuzzes up a bit, switch focus back to your hand and it will be crisp while the background blurs.
What we do in this effect is selectively alter depth of field so specific parts of the image are blurry when they would not be in a real scene. We either break or flop the processing rules above, and your brain attempts to make sense of what it sees.

Background 3 – Effects of Lighting, Color and Detail on Perception

Also important to your software are the representation of lighting, color, and details in an image. Here are some rules your brain uses when it processes these variables from an image:

1. Real scenes are more detailed than man-built models. (Think of the difference between matchbox cars and real cars).
2. Real objects vary in their coloration more than model objects, and are often weathered. (toy companies use this often now, in battle-damaged toys, to increase their realism).
3. Lighting conditions are different between real objects and model representations. (Most models are seen indoors, under direct artificial light as opposed to in full spectrum sunlight).

Two notes before beginning. First, when I recommend specific feathering values (like 50px) I am basing these values on the images included for PSD Plus members. If you are using your own images, or the 600px wide versions here, your values may need to be lessened somewhat.
Second, I suggest saving the various selections we’ll make whenever this tutorial creates a selection area. I’ve saved them in the PSDs that come with PSD Plus membership, but it is a generally good practice that can save you a lot of time on any project, especially when making complex masks you might need again. The save selection dialog looks like the image below, and is accessed via Select > Save Selection.

Image 1: Applying the Diorama Technique to a Landscape Image

This is a picture I shot in Shinjuku, Tokyo in October 2008. Your brain is telling you a few things about it:

1. Almost all the picture is in focus, but there is not a ton of close-up texture and detail; the data was probably collected far away from the image contents.
2. It knows that you are mostly looking at large things – cars, buildings, et cetera; since they are small in this image then you must be far away.
3. The objects at the fore have slightly higher detail than objects further away, and the loss of detail is consistent with landscape references you’ve analyzed before.

Combined with the depth of field information it has gathered, your brain comes to this conclusion: You are looking at a scene of large objects, taken from far away.
Now that we know what rules our software uses to come to this conclusion, it’s time to break them.

Step 1: Selecting a Focal Point

Choose a portion of the image that you’d like to highlight. There is really just a single rule here: the selected focus should be in the mid-ground. Here, we will use the trucks on the street. Follow the instructions below.

Step 2: Creating and Feathering a Selection

There are several types of selections we can use for this technique, but in this case we’ll use a shifted oval. Since Photoshop doesn’t allow rotation of selection marquees, we have to use a path and then make it a selection.

Convert the work path to a selection.

Invert the selection and then apply a Feather, as indicated below.

Step 3: Applying Simulated Depth of Field

We’ll use the Lens Blur filter to blur the image in the area outside our focal point. The Lens Blur filter works outside the selection (i.e the selected area is left alone while the area outside the selection takes the effect), so do not invert this selection.

Step 4: Applying Lighting Effects

First, we open the curves dialog (Command + M or via Image > Adjustments > Curves). Drag the curve slightly upwards to blow out the image.

Next, we use the Omni light to simulate an all-over artificial light. You can access it from Filter > Render > Lighting Effects.

Step 5: Adjusting Color

Toys and models frequently have deeper color and are more vibrant than their real-world counterparts – partly because they are not subjected to the same dust and weathering and partly because kids like bright colors. This is easy to achieve by pumping up the vibrance and saturation a bit. Set Vibrance to +30 and Saturation to +40.

Step 6: Final Step for Image 1

You might notice that the previous step pumps up the blue in this image to a distracting level. After applying the Vibrance/Saturation settings, we fix this by using auto-color under the Auto-Color menu (Command + B), and our first image is complete!

Image 2: Applying the Technique to a Flightline of Airplanes

This image is an US Air Force file photo of F-22 Raptors on a flightline. It can be found here. What makes this image look real as opposed to a diorama of the same scene?

1. There is a high level of detail in all the objects shown.
2. The background is very detailed for how far away it is.
3. The lighting is consistent with sunlit aircraft.
4. The nearest aircraft is the most detailed, with rear aircraft losing details, as expected.

Really, it’s no different than our street scene. Where our execution will differ is in the precision and number of our selections. Where in the city scene it was enough to select a single feathered ellipse, here we must take care to mask the details of the aircraft in the middle, which will be our focus.