Friday, March 31, 2006

Depth of Field

An original Photoshop® Tutorial

Requires Adobe Photoshop CS or later. An intermediate skill level is recommended, and you should be comfortable with making detailed selections. If you need more guidance for making the selections in this tutorial, please review my original DOF tutorial. To follow along, download the image below:
downlaod file download file
This tutorial provides an introduction to using the Lens Blur Filter, a tool added to Photoshop CS (version 8.0). If you have an earlier version of Photoshop, please see my earlier DOF tutorial, written prior to the release of Photoshop CS.

Download a larger version of this image.
[Source images provided by Digital Photography Review.]

In Search of the Gradual Blur

Many digital cameras tend to have little or no control over depth of field, leading the photographer to enlist the help of Photoshop to achieve variations on this effect. The goal of this tutorial is to manipulate a photograph into simulating a shallow DOF exposure, a technique typically controlled on manual cameras by setting a larger aperture (e.g. f/2).
The problem that I have seen with other tutorials on the same subject is that they tend to simply blur the background of the photograph. Sometimes, this may be all that is needed; however, a background tends to contain much more depth (i.e. objects vary in distance from the subject). A true representation of shallow DOF would show a gradual blur, with the blur becoming more intense for objects that are farther away.

Paint That Channel

In the Channels palette, create a new channel (Alpha 1) and make all channels visible by clicking on the channel visibility next to RGB (the eye icon should appear for all channels). Be sure that the new Alpha 1 channel is still selected.
Set your default colors (D), select the Radial Gradient Tool Radial Gradient Tool, and drag in the direction of the arrow indicated in the image above.
Make a selection around the back card and its coaster, fill your selection with #EEEEEE, then deselect.
Make a selection around the middle card and its coaster (it's okay to over-select on the left side), fill your selection with 50% Gray, then deselect.
Make a selection around the front card and its coaster, fill your selection with Black, then deselect.
If you toggle off the visibility indicator in the RGB channels, your Alpha 1 channel should look like the image above. Before moving onto the next step, toggle on the visibility for the RGB channels and turn off the visibility for the Alpha 1 channel.

Next Stop: Lens Blur

Go to the layers palette and select the Background layer, then duplicate this layer (Ctrl+J on PC or Command+J on Mac) and name your duplicate layer DOF.
With the DOF layer selected, go to Filter > Blur > Lens Blur... and use the settings from the image above.


The image should now resemble my own, at the bottom of this page. Compare your result to the true DOF photograph at the top.
This is intended to be a simple introduction to a very powerful tool, the relatively new Lens Blur Filter. Use it as a launch pad for experimenting further, to see and understand how each setting affects the image.


Friday, March 17, 2006

What Have I Been Missing?


(Editorial originally published in Mojo, Sep 2005)

You might call me dumbfounded as I listen to "Like A Rolling Stone" for the seventh time in succession, were it not for the act of writing these very words. Immediately after reading Greil Marcus' somewhat adulatory synopsis of Bob Dylan's masterful song, I excavated the allegedly cave-like record in a frenzied attempt to discover the spinning walls and flickering lights that I must have overlooked during the countless other times I've listened to this tale of … knights, dragons, and transvestites?

Upon listening much more carefully than on past occasions, I can confirm my previous observations that this must be one of the best songs ever recorded, telling a Karmic story about a pompous high-society girl left destitute after her wealth is stolen—once oblivious to the "Riff Raff," she is now an involuntary member.

I only wish I had the same synapses firing in my brain to visualize countless instruments scatter across separate journeys, each one shooting off to the next like a series of ricochet bullets; witness the enveloping sound on a weight scale as the meter jumps from 1 to 2 million; find this mysterious, empty road of ghosts with unsurpassable, magnanimous mountains; and fathom exactly when the song gets away, who gets it back, and just how it subsequently loses its sound. I would also greatly enjoy the opportunity to study the incredibly detailed charts of measurements that must exist somewhere, acquired from some sort of pressure gauge on Dylan's nasal flow during the song's recording.

Until now, I have considered myself to be an avid music fanatic for most of my life. It has become painfully clear that I have been missing out on key musical experiences, such as transporting myself in time and space to the actual recording of a song, after following a magical and mystical trail of fairy dust left behind by a bunch of siblings of a sorcerer who is a vague acquaintance of mine. Please sign me up—I want in!

Ice Is Not Blue

A discussion on conceptual design

"If you can't beat 'em, join 'em!"

[Originally published Jun 2005]

It may be an obvious concept, but upon witnessing various ice-renderings colored in blue tones by other artists, it became very clear that as designers, we ought to study an object thoroughly in order to simulate a realistic appearance.

Visualize ice.

Why would ice be blue? Is it the color's association with a cold sensation or the blue appearance of water in an ocean that overpowers our common sense? Whatever the reason, the association can be so powerful that our renderings of ice simply lose their appeal when painted in only grayscale tones mixed in the colors of any objects that are represented behind the ice (i.e. the true color of ice).

To work around a somewhat irrational perspective, we might choose to display the ice on a blue background, allowing the color to blend through the translucent object, while maintaining a realistic appearance (as in the image above).

"What color is chrome?"

I often remember this question once asked of me when I was attempting to render a paper clip. Our natural instinct seems to think of chrome as consisting of sharp gradients of silver and/or gold, which is not necessarily accurate. A thorough examination of the actual object reveals the color to be very silvery and shiny, yet also mixed with a reflection of objects in front of the chrome. That is, whatever is between you and the chrome object, the face of that item (which you cannot see) is being reflected in the chrome object (albeit distorted).

If there is a complimentary color to ice, then it must be chrome.

Visualize chrome.