|Kodak digital camera tips about image quality |
Mark Peters : April 6th 2005 - 08:30 CET
Kodak digital camera tips about image quality : With many choices available for printing digital photos - from stand-alone home printers to printing at in-store kiosks and minilabs to ordering prints online - digital camera owners have many factors to consider. The single most important factor is image quality - and that can be subjective, at best. Different people may have different opinions of an image. Based on decades of studying image science and the ways people capture, view and share pictures, Kodak researchers have put together the following tips for evaluating image quality. Consider these guidelines when deciding which printing choice best meets your needs.|
Kodak image quality - Subjectivity|
Kodak researchers use at least 30 people in each focus group that evaluates print image quality. Rounding up 30 people may not be practical, but you can ask several acquaintances to share their opinions. They may point out details of a test photo you might otherwise miss. Most retailers have test photos you can examine in their stores. Overall image quality may be similar among a group of prints, but evaluating individual attributes of each picture helps you select the image quality you seek.
Kodak image quality - Weigh factors
Sharpness - Look for sharp edges but beware of over-sharpening, which can cause unnatural looking artifacts in hair or other high-frequency regions in the image. Over-sharpening can also result in a halo artifact, in which objects appear to be outlined by a fine white line.
Density - The print should not be too light or too dark.
Color Accuracy - Color should look real, accurate and pleasing, similar to the captured image.
Tonescale and Contrast - Color transitions should be smooth and not exhibit contouring in regions of slowly changing density. Highlights (very light areas of a picture) should not be blown out, shadows should not be murky or blocked up, and blacks should be dark and neutral.
Noise - While pictures taken at ISO speeds of ISO 400 and higher can exhibit some graininess, prints should not have noticeable granularity or dots in smooth areas such as sky, faces etc.
Gloss - The print should have an even, uniform gloss across the surface of the photo, and should resist smudging.
Kodak image quality - Consider the source
A picture can only be as good as the digital image with which you start. Depending on the manufacturer, a 2 MP digital camera can create image files large enough for good 4 x 6-, 5 x 7-, or even an 8 x 10-inch prints, but any cropping of the picture reduces the file size, and can result in an unsharp print. Consider the camera; its resolution, sensor quality and lens help determine the quality of the printed image. Camera manufacturers balance color in different ways based on their own concepts of color and how an image should look. When comparing different printers, be sure the test pictures come from the same digital camera, to obtain an accurate comparison.
Kodak image quality - Mix it up
When judging image quality, use a variety of images: an outdoor daylight scenic, a portrait shot, an action photo, and an indoor flash candid. Compare zoomed-in close-ups and wide-angle landscapes. The more scenes you review, the more accurate your overall assessment will be. Because image quality is very scene-dependent, try to evaluate prints that are typical of the photos you normally shoot. Important colors to evaluate inclued skin tones of various ethnicities and sky.
Kodak image quality - Viewing conditions
The lighting you use when viewing images can have a significant effect on each picture's appearance. Fluorescent lights may cause an image to look very different than it would in a home environment, where natural light gives a photo a warmer, pleasing appearance. When evaluating prints, Kodak researchers recommend a light source that simulates Standard Illuminant D50 as defined by the CIE (Commission Internationale de l'Éclairage) to get the truest sense of image quality. If D50 lighting is not available, prints should be viewed outdoors or next to a window (north facing is best).
Kodak image quality - Image alteration
Images printed via a computer, as opposed to directly from a camera or memory card, can be color corrected or altered using software. For example, printing with a Kodak EasyShare printer dock using Kodak EasyShare software allows for three basic settings in the color correction tab of the advanced preferences driver window - Natural, Enhanced or None. The Natural color correction is the recommended setting and delivers clean, realistic color. The Enhanced setting delivers more saturated colors compared to the Natural setting. The None setting allows the user to print without any color correction. When printing directly without a computer via direct camera docking (e.g., ImageLink print system or PictBridge) or memory cards, the printer only uses one color correction setting (with the printer dock, this is similar to the Natural color setting in the printer driver). In addition, with a single touch of the auto enhance button with Kodak Perfect Touch Technology on the Kodak EasyShare Printer Dock Plus, people can create real Kodak pictures that are better and brighter.