Bitmaps and Vectors Image

              The urge to dig in and start doing is understandable, but it’s not always advisable. Sure, you could fumble your way through many Photoshop techniques and possibly achieve the results you want. But you’ll enjoy the experience more, and work much more gracefully, if you understand some of the concepts at the core of Photoshop use. Of course, that’s why this The most important chapter, so you won’t be scratching your head in puzzlement later.

*---------------------------------------------------------------------------------------------------------------------------*

    Photoshop was originally created to work with bitmap images, but you can also work with vector artwork. A bitmap or raster image is based on a grid of pixels, with each pixel assigned a particular location and color value. Pixels are ideal for working with photographs or other continuoustone images, because they can represent subtle gradations in color and shade.

   There is a downside to working with pixels, though. When you have a specific number of pixels, scaling an image to a larger size means either Photoshop has to guess what the additional pixels would be or, if you keep the same number of pixels, each pixel is larger and you lose the subtleties in the original. When you scale an image to a smaller size,
   Photoshop discards pixels, which can give you less-than-desirable results as well. The alternative to bitmap, or pixel-based, images are vectors. Vector graphics are composed of lines and curves that are defined mathematically. Because they’re not created pixel by pixel, you can resize vector graphics up or down without losing their crispness. When vector graphics are appropriate for your artwork, they’re great. Rely on vectors for text and illustrations, such as many logos. But stick with bitmaps and their ability to display subtle gradations when you work with continuous-tone images, such as photographs.  Sometimes, to work with vector artwork in Photoshop, you need to convert it to a bitmap by rasterizing it.