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Displace Filter, Page 6 - Conforming to Irregular Surfaces

Just when you were thinking there wasn’t anything more I could dredge up about this funny tool… this page deals with an unbelievably useful application for the versatile Displace filter. We’re up to page six; the next pages are getting into increasingly practical matters, and I will be getting increasingly general with the details. As I said at the beginning, the point here is to draw back a curtain and give you a glimpse. It’s up to you to fill in a lot of the blanks with your own technique. If you have been following along to this point, I can afford to toss off a sentence or two and expect you to grasp the general point.

If you are an art director or a graphic artist or an illustrator or a photographer, sooner or later you are going to need to know how to do what this page deals with; that is, you will need to make one layer in a Photoshop file appear as if it is part of an underlying layer. The simple way to do this is to tinker with the Layer Blending Mode of the top layer — screen or multiply or soft light or overlay — each of these enables qualities (such as texture) to show through the top layer. This can be extremely effective, but only if the underlying layer is flat, or close to it. If the substrate is wrinkled or irregular, blending modes won’t do anything to change the shape of the object on the top layer. The illusion is ruined in that case.

If this sounds reminiscient of the previous page, warping a shape, you’re right. Almost. The big difference between this technique and the previous is that we are going to make our DMap from the image itself. Previously we made up a DMap from scratch to accomplish a general goal, and were more or less happy to live with what we got, or fool around until we got something more pleasing. In this case, we need to fit an image to another image, and thus the DMap has to come from that underlying image. This will become clear as we look at three examples: a wrinkled shirt, a brick wall, and a sophisticated shadow.

In each example I am going to show the pieces, a representation of the DMap and the final result with not too much explanation in between. Here’s what you need to know to understand. Each case represents a layered Photoshop file with at minimum two layers: the irregular base shape and the image that needs to conform to it. I like to duplicate the base shape into a new RGB file; I then apply the Gaussian Blur filter to the red and green channels. Don’t obliterate them, just knock the edge off the detail. Settings of 2 – 5 work fine for little, low re files. The next step is optional, but it works well for me: apply the Filter>Other>Offset filter to shift the red and green channels in opposite directions from each other. For example, shift the red channel 4 pixels up 5 pixels left; shift the green channel 3 pixels down, 5 pixels right. Numbers aren't critical, and they can be equal or unequal. Remembering that the blue channel will have no effect, you may either leave it alone or fill it with white or black or whatever. Then, as always, save it as a .PSD file.

To repeat: Duplicate the layer to a new file; blur the red and green channels slightly; offset the two channels so they are no longer in register; save as a .PSD file with a name you will remember. That’s it. You won’t believe what this is capable of, so I guess it’s time to stop teasing and show you.

This first scenario is not completely made up. I’ve shot T–Shirts in my studio for designers who then had to apply the ornaments that the “real” is going to have when it has been made! We try real hard to keep the shirts flat where the applied image will be, but softly wrinkled boyond that area. It’s a pain. Watch how it comes together. We start with a shirt and some artwork. Create the DMap as described above (for space reasons I've only shown one of the two channels, and that one reduced from actual size), and apply the Displace filter to the art work. Now we can use the familiar blend modes and it all pulls together.

blank shirt
artwork for the shirtDMap for the shirt
distorted artworkartwork blended with shirt
final shirt image

The next trick involves — brick! Who knows, maybe someday you’ll be asked to apply a sign to the side of a building. Not that far fetched, is it? Do you want all of your signs to look like billboards? Not likely. We start with a brick wall, and create the art work in Illustrator. After rasterizing in Photoshop, the Free Transform command fits the sign to the perspective of the wall. The rest of the sequence is identical to that above — duplicate the brick layer, blur and offset red and green, run Displace (as before, I only show one of the two DMap channels here) and then fiddle with blend modes until happy. In this case, the distortion effect is quite subtle, so I also ran lighting effects on top of everything at the end to give more of a sense that the sign is somehow part of the brick surface.

brick wall
wall artworkDMap for wall sign
distorted sign
final image of wall siign

The grand finale for this page deals with shadows. (My illustration for this part is a nod to a fantastic photographer and Photoshop artist, John Paul Caponigro. My little demo file pales in comparison to his fine art work. I’d strongly suggest checking out his book “Adobe Photoshop Master Class”. In addition to teaching some very useful collage techniques, Caponigro has material on aesthetics and theory you won’t easily find anywhere else. He also has a web site with an area called MasterClass, also full of beautiful images and very useful information.)

Everyone needs to make a shadow at some point, and not all shadows fall on flat, smooth surfaces. There are lots of shadow tips out there, some more sophisticated than others, but they mostly all deal with the shape and Layer Blending Modes. To make this shadow, I started with the landscape base. The hovering stone is a second layer. I duplicated the stone layer; I then rotated and stretched the duplicate layer with Free Transform, and with “Preserve Transparency” checked I filled it with black. I unchecked “Preserve Transparency” and blurred the shadow shape (sneaky trick — use Quick Mask and the gradient tool to make a selection that permits you to apply the Blur filter more at the far end of the shadow than at the near end — just like real shadows!), and then set it to Multiply at about 40% opacity.

It’s not an awful shadow like this, but it needs to be even better. You know the rest by now. Create a new .psd file from the “landscape” layer. Blur the red and green channels in this new .psd file (which will be the displacement map) and offset them in opposite directions. In this example I show both channels of the DMap. Run Displace on the shadow layer of your main image. I also added a layer mask to fade the shadow slightly as it gets further from the stone. Tell me this filter isn’t just too great!!

sandy landscape basesimple shadow
sand DMap channel Asand DMap channel B
final image

Too cool. This gets addictive, but that’s enough for this topic. On to page seven: Volumetric Distortion.

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