DIGS: Pixels, image resolution and portraiture lighting

Joe Liske, Jim Eaton and John Triebe visiting before DIGS meeting; photo by Bill Brennan.

Joe Liske, Jim Eaton and John Triebe visiting before DIGS meeting; photo by Bill Brennan.

Bill Brennan

At the January meeting of DIGS, the SaddleBrooke Photography Club, Bill Todd presented a program that covered the fine points of Pixels and Image Resolution and John Triebe demonstrated how to set up a virtual portraiture studio.

Camera marketers use a number of megapixels to differentiate their cameras from their competitors. During the past several years we have witnessed a race among camera manufacturers to produce a camera that could capture the highest number of pixels.

So, what is a pixel and why are pixel counts important? Pixel is a word invented from picture element. The technical definition: A pixel is the basic unit of programmable color for a computer display or for a computer image. Each pixel contains three colors: red, green and blue. Through computer programming the three colors can be mixed to form 256 shades of color from pure white to pure black.

As Bill Todd pointed out, pixel counts become important when we want to make large prints of our images. Why? When we share an image over the internet or show an image on a computer screen, all we need are 72 pixels per inch for a good image. However, for a good printed image we need between 240 and 360 pixels per inch.

Image resolution is the number of pixels per inch. Photoshop software makes it relatively easy to prepare an image with the desired size and resolution.

John Triebe’s presentation shifted the focus of the meeting from image processing to making portraits without a portrait studio.

With Jim Eaton as the model, John showed how photographers can use a series of three or four electronically synchronized flash lighting units to create a virtual portraiture studio. Looking at Jim’s portrait with a black background one would never know that it was made in the Coyote Room with murals on the walls.

Dan Garand announced that the January project was self-directed black and white street photography and the February project will be the Tucson Rodeo on February 21 when Canon will let us try out their sports photography equipment: the same equipment as photographers used in Russia at the last Olympics.

To find out more about DIGS, visit the website at www.digssouth.org or come to a meeting on the second Saturday of each month (September through June) at 8:30 a.m. in the Coyote Room at the HOA1 Clubhouse.