Its relatively rare to come across an original image thats completely free of any imperfections. Even if it is, various enhancements will probably be necessary to refine an image at some stage.
Its relatively rare to come across an original image thats completely free of any imperfections. Even if it is, various enhancements will probably be necessary to refine an image at some stage.
Its important to evaluate your image using a sensible on-screen dimension. Anything less than 100 per cent will display an approximation of the original that can, at worst, severely compromise the visible quality of the image (Figure 1). At 100 per cent, the image will be displayed with each screen pixel displaying one image pixel. Increments of 100 per cent are best. At 200 per cent, four screen pixels, 2 x 2, describe a single image pixel and so on. Anything in between becomes a compromised approximation once again.
Even with the highest available screen resolutions currently offered by PCs, displaying an image at 100 per cent will often only show a small portion of a picture. Under 100 per cent, you can get away with 50 per cent and smaller steps of half again (25 per cent and 12.5 per cent), as these sizes basically remove whole pixels uniformly, reducing resolution without introducing arbitrary distortions.
Common imperfections include a lack of sharpness, imperfect exposure and/or colour balance, red-eye from flash photography and dust and other blemishes in scanned images. If several things need attention in an image, including sharpening, leave the sharpening to last. Another tip: if youre re-sizing an image, say, to reduce it to fit a Web page, sharpen after re-sizing, as the size change will soften the image further.