Monday, March 31, 2008
May 2008 HelpLine
When New Tech Meets Old Tech
Q) I've been considering changing from a CRT to an LCD display. Having a wide LCD TV, I know that it can display an image in its proper 1:1 aspect ratio or distort it to fill the screen. I was allowed to try a widescreen LCD at home (no manual), and an image in Photoshop looked like it was stretched horizontally, regardless of its overall display magnification. I set the selection marquee to a 1:1 Fixed Ratio and, sure enough, I got a rectangle. That doesn't go! My question is, can one expect widescreen LCD monitors to have settings to switch between displaying the image in its proper 1:1 aspect ratio, as opposed to stretching it to fill the screen, and at a true 1:1 image aspect ratio, are the sides of the screen black and useless, or available for parking toolboxes?
A) Before I answer your question, I need to clarify some things about displays. With the advent of digital television (DTV), more and more people have high-definition video displays in their living rooms, great rooms, home theaters and home offices. One of the biggest changes that these displays bring is a different aspect ratio.
The old television system has an aspect ratio of 4:3 (width to height). High definition has an aspect ratio of 16:9. Since there's still a great deal of programming that has been produced at 4:3, there needs to be a way to deal with differences in aspect ratios. (Even though I'm talking about television programs, this also affects digital photography. HD sets have video inputs that allow you to connect your camera so you can present your images on a high-definition display. The latest and greatest sets even have card reader slots. All you need to do to display your images is insert your memory card.)
There are several options that can address the 4:3 "shortcoming." The first is to stretch out the image so it fills the screen. This method doesn't respect the original aspect ratio and it makes everything look wider. (If you thought it was difficult to answer the question, Does this dress make me look fat?, you might want to avoid this setting.)
A second option respects the original aspect ratio of the image. Your image fills the display top to bottom, but the left and right sides of the screen will have black or gray boxes, or pillars. This is known as pillar boxing. This is the most accurate way to display your image—it respects the aspect ratio of the original image.
There's a third option, which keeps the original aspect ratio of the image, but zooms in on it to eliminate the black bars at the left and right of the image. While many people are distracted by the black bars and prefer this method, it crops the top and bottom of the image, so you lose parts of your original composition.
I think, however, that Lew's question deals with widescreen monitors that are connected to a computer. In this case, a specific standard doesn't lock us into a display like our television system does. When you hook up a widescreen display to your computer, you want your video card to output the number of pixels that can be displayed on the LCD. For example, if your display is 1440 x 900, then your video card should output 1440 x 900. It should create a desktop with that format. There's no reason for the LCD to "stretch the pixels" unless your card won't support the resolution, nor is there any reason for black bars on the left and right.
And, as Lew pointed out, distorting the desktop changes squares into rectangles-and makes all the people in your pictures look fat. And do you really want to go there?
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