Friday, July 27, 2012
Make Your Own Digital Drape Backgrounds
A while back I wrote a post on using gray backgrounds while shooting to make digital background replacement quicker and easier than "green screen" chroma-keying (Digital Backgrounds? Ditch the Green and Go Gray!). Whether you use gray or stick with green-screen, here's a quick and easy way to make your own digital backgrounds that look like classic draped-fabric, without having to hang up anything...
This quick method requires Photoshop CS2 or later. It uses the Displacement Map feature in Photoshop to make the drape backgrounds look realistic. Follow along with the steps below to get started.
Start with a blank new image file that's the size in pixels of your camera's images. Fill the background with black, select the paintbrush tool with a color of white and an opacity of about 90%, and a medium-hard edge (about 70-80%). Using the brush, freehand-draw some mostly vertical stripes on your black background, as shown in the example above. The straighter you make the lines, the more regular the drape will appear to hang in the final image; adding some curves and bends makes a more irregular and often more natural-looking image.
Once you have your striped image made, make sure the image is flattened, select the background layer, and use the "Shape Blur" tool to make it look like draped fabric (From the Photoshop main menu, Filter->Blur->Shape Blur). A dialog box like the one below (from CS3) will open:
I'm using a spatter shape from the included shape libraries, as you can see in the dialog box; you can experiment with other shapes to see what gives the effect you like. Adjust the pixel size in the dialog box to get a pleasing pattern of dark and light areas that look like folds in a drape background. When you're happy with the preview of the image, click on OK and let the filter run. You should wind up with an image that looks like the one below:
Note that using a harder-edged brush to make the initial "stripe" image, and a lower radius in the Shape Blur dialog box, will result in a more sharp-edged drape image; and using a softer brush and larger radius in a more blurry image. Keep those concepts in mind as you make the image, to produce the effect of a more or less blurred background drape.
This image will be both our base for our drape, and our displacement map we'll use in just a bit. For now, save the image as a PSD file on your hard drive, but keep the original image open.
To add some color to our drape, you can quickly paint up a new image (with the same resolution as the drape image), or use an existing image. For this example, I made a quick "painterly" background using soft brushes and a bit of motion blur, as shown below:
Paste this color image as a new layer on top of your created grayscale drape image, and set the blend mode of the color image to "overlay." You may want to adjust the levels of the background drape image if the color overlay doesn't have enough contrast. Your layer palette when set up this way should look like this:
Next, we're going to make the color overlay "fit" the drape background better by using the Displace filter. This filter uses a grayscale image to displace the target layer in 3D. We'll use the saved version of our drape image as the displacement map to make the color overlay be displaced in 3D to fit the underlying drape image. In the layer palette, make sure the color overlay layer is selected, then select Filter->Distort->Displace from the menu. A dialog box like the one below will open:
Leave "Stretch to Fit" and "Repeat Edge Pixels" selected as below; as for the vertical and horizontal scaling, start with values around 100-200; after you apply the displacement map, if you're not happy with the results, then Undo the filter, and try new values until you like the result. When you're finished, your layered image will look something like this:
That's really all there is to it. Save this image as a PSD file, and keep it in a library of digital backgrounds for you to use. Experiment with the scaling and parameters of the shape blur and displace filters -- you can get all sorts of interesting results. Try different shapes and patterns of stripes (or use circles, or waves, or other shapes) in the base image before the shape blur. Experiment and have fun! Using this method, you can create a lot of varied background looks in a very short time, that you can use over and over again.
Digital Backgrounds? Ditch the Green and Go Gray!, dropping these new backgrounds behind portrait shots is quick and easy. I started with the image above, used the techniques in the article, and wound up with this final image:
I keep a library of all sorts of backgrounds, and typically set aside half a day every month or so to make new backgrounds for my library. The more options you have, the better!
Have a shot at making your own backgrounds -- it's fun and easy.