Posts

Showing posts with the label raster images

Raster Image File Formats

Image
  Raster Image File Formats The most common Raster image file formats, the  most important for cameras, printing, scanning,  and internet use, are  JPG, TIF, PNG, and GIF.   •JPG .JPG is the most used image file format. Digital cameras  and web pages normally use JPG  files – because JPG heroically compresses the data to be very much smaller in the file.  However, JPG uses lossy compression to accomplish this feat, which is a strong downside.  A smaller file, yes, there is nothing like JPG for small, but this is at the cost of image quality. This degree is selectable (with an option setting named JPG Quality), to be lower quality  smaller files, or to be higher quality larger files. In general today, JPG is rather unique in  this regard, using lossy compression allowing very small files of lower quality, whereas  almost any other file type uses lossless compression (and is larger). The meaning of Lossy  is discussed Below....

Basics of Photoshop

Image
  Basics of Photoshop What is Image? A Visual presentation of something is called Image eg: pictures, photgraphs. Basics of Photoshop. Images are of two types : Raster Images Vector Images Raster Images: Raster Images is a way to represent digital  images.  Eg Scanning photo. Raster Images are  also  know as bitmap. When a raster image is  created,  the image on the screen is converted into  pixels. Each pixel is assigned a specific value that determines its color. This format uses the  red, green, blue (RGB) color system. An RGB value of 0,0,0 would be black, and the values  go all the way through to 256 for each color, allowing the expression of a wide range of values.  In photographs with subtle shading, this can be extremely valuable. Raster graphic are resolution-dependent and cannot be scaled up arbitrary without loss of apparent  quality. Some Raster Images : Here fish is formed by blue color pixels. As the image is crea...