Wednesday, May 23, 2007
Dealing With Viewing Distance
Creating accurate viewing conditions is critical when evaluating your images, and it's something no one seems to be talking about—until now
There's a fundamental flaw in digital imaging today. You simply cannot view a pixel-based image on a computer display that gives a true interpretation of what it will look like printed on paper.
I'm not referring to color, color management and the ability to soft-proof using accurate display profiles and printer profiles as a high art. No, it's even more basic than that. A computer display (a monitor, for those who are uninitiated) has essentially 72 pixels per inch (ppi). While some operating systems allow for higher settings, such as 96 ppi, no display can be considered anything but a low-resolution proxy to the final output. Add to this the complication that there are two distinct flavors of displays: CRTs, which are glorified TV tubes, and the newer digital LCDs.
CRTs are soft, fuzzy and dim, which makes it difficult to work on photographic images and have a clue of what your images really look like. LCDs, on the other hand, have a degree of sharpness that's a great improvement, yet still lack in resolution.
So, how do you know what your images will look like when printed? Well...you print them. It may seem an overly simple answer, but it's the only way to judge issues of image sharpness, smoothness of retouching and seamless composites.
In the past, conventional wisdom had people viewing their images at a 100% zoom within Photoshop to accurately see the “pixels.” This shows one image pixel per screen pixel. Viewing at 100% avoids the issue of pixel dithering (making pixels into halftone dots)—a real problem for CRTs. However, a high-resolution digital image at 100% zoom bears little or no relationship to the actual size of the image when printed. A 300 ppi image at a 100% zoom on a display at 72 ppi will be about four times the physical dimensions of the printed image. In essence, you're “seeing” your image through a 4x loupe. It's way too big to correctly perceive the image and judge accurately.