| FAQ pages...6 |
| 21. Why a image changes few original colors, if GIF compression is lossless ? Ans.If bit mapped images have pixels with colors, not present in the 256 color map of GIF encoder, new colors are seen in the saved image. All GIF image editors or application programmes do not have the same set of 256 color map for constructing or reconstructing a GIF image. This problem could be avoided by increasing the number from 256 to 4096 or higher number. 22. Why some JPEG images have distortions ? Ans. JPEG is a lossy but highly effective method of compresssion of images where more than 256 colors are used. JPEG compression can reduce file size by a factor of 20 without causing any detectable distortion. Images from camera or scanner are too large in size, if high resolution is used. Higher the resolution, more is the file size. To make an image downloadable in a slow internet system, designers use very high level of compression in JPEG algorithm. This is achieved by reducing quality or emphasis of finer color changes. Thus original colors in certain areas get distorted or changed to a different value. There may be visible distortion at edges or where color changes drastically. JPEG compression method allows highier or lower degree of compression depending on the compression level or quality used. An image file may be compressed by a factor of 100 with some perceptible distortion. 23. How to make an image fade for using in background? Ans. The image used as background in this page has been faded from a normal scanned image of a color photo. Any photo editor application has tools for color ehancrment or image control.Apart from brightness or contrast, there is a gamma scale. Increased gamma value with slight increase in contrast fades the image |
| Last updated: June 20, 2005 |