Basics of Photoshop

What is Image?

A Visual presentation of something is called Image eg: pictures, photographs.

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 created using pixel (no digital camera is used), hence the image is raster image.

Vector Images:

•  Vector graphics is the use of geometrical primitives such as points, curves, and shapes or —all of which are based on mathematical expressions—to represent images in .
• Vector Images can be scaled up to any size without losing any details.

Example showing effect of vector graphics versus raster graphics. The original vector-based illustration is at the left. The upper-right image illustrates magnification of 7x as a vector graphic. The lower-right illustrates the same magnification as a raster (bitmap) graphic. Raster images are based on pixels and so when scaled there is a loss of clarity, while vector-based graphics can be scaled by any amount without degrading quality.

STUDENT WORK :
STUDENT NAME : NARESH