New To Digital Graphics

New To Digital Graphics?

This is a guide to any considerations you may have for when undertaking a Digital Graphics Project

• Pixels 
• Raster and Vector images
• Bit Depth 
• Colour
• Applications of interactive Graphics
• Finished output considerations

Pixels 

Pixels are small dots in which cover a monitor. They have many colours inside them, the less the colour the less the quality of image.

RASTER IMAGE

What is raster image?

A raster image, also called a bitmap, is a way to represent digital images. The raster image takes a wide variety of formats, including the familiar .gif, .jpg, and .bmp. A raster image represents an image in a series of bits of information which translate into pixels on the screen. These pixels form points of color which create an overall finished image.

When a raster image is created, the image on the screen is converted into pixels. Each pixel is assigned a specific value which determines its color. The raster image system 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 color values. In photographs with subtle shading, this can be extremely valuable meaning a better quality image

When a raster image is viewed, the pixels usually smooth out visually for the user, who sees a photograph or drawing. When blown up, the pixels in a raster image become apparent. While this effect is sometimes a deliberate choice on the part of an artist, it is usually not desired. Depending on resolution, some raster images can be enlarged to very large sizes, while others quickly become difficult to see. The smaller the resolution, the smaller the digital image file. For this reason, people who work with computer graphics must find a balance between resolution and image size.

Resolution refers to the number of pixels per inch (PPI) or dots per inch (DPI) in the image. The higher the resolution, the greater the number of pixels, allowing for a greater gradation of color which will translate better as the image is enlarged. Of course, the more pixels, the more individual points of data to be stored, as well. For high quality photography, a high DPI is preferred because the images will look more appealing to the viewer. For small images which do not need to be blown up, or when quality is not important, a low DPI can be used.

Common File Types

These file types are common and most widely used file types used today. The file types we will be looking at are

bmp.

jpg.

Png.

Gif.

Tiff.

BMP

The BMP File Format, also known as Bitmap Image File or Device Independent Bitmap (DIB) file format or simply a Bitmap, is an Raster graphics image file format used to store bitmap digital images, independently of the display device (such as a graphics adapter), especially on Microsoft Windows and OS/2 operating systems.

The BMP File Format is capable of storing 2D digital images of arbitrary width, height, and resolution, both monochrome and color, in various color depths, and optionally with data compression, alpha channels, and color profiles.

JPG

JPG file extension. This is the right format for those photo images which must be very small files, for example, for web sites or for email. JPG is often used on digital camera memory cards, but RAW or TIF format may be offered too, to avoid it. The JPG file is wonderfully small, often compressed to perhaps only 1/10 of the size of the original data, which is a good thing when modems are involved. However, this fantastic compression efficiency comes with a high price. JPG uses lossy compression (lossy meaning "with losses to quality"). Lossy means that some image quality is lost when the JPG data is compressed and saved, and this quality can never be recovered.

PNG

This document describes PNG (Portable Network Graphics), an extensible file format for the lossless, portable, well-compressed storage of raster images. PNG provides a patent-free replacement for GIF and can also replace many common uses of TIFF. Indexed-color, grayscale, and truecolor images are supported, plus an optional alpha channel. Sample depths range from 1 to 16 bits.

GIF

The Graphics Interchange Format (GIF) is a bitmap image format that was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web due to its wide support and portability.

The format supports up to 8 bits per pixel thus allowing a single image to reference a palette of up to 256 distinct colors. The colors are chosen from the 24-bit RGB color space. It also supports animations and allows a separate palette of 256 colors for each frame. The color limitation makes the GIF format unsuitable for reproducing color photographs and other images with continuous color, but it is well-suited for simpler images such as graphics or logos with solid areas of color.

TIFF

Tagged Image File Format (abbreviated TIFF) is a file format for storing images, popular among Apple Macintosh owners, graphic artists, the publishing industry,[1] and both amateur and professional photographers in general. As of 2009, it is under the control of Adobe Systems

PIXELS

What are pixels?

Pixels are in images, pixels are dots used to display an image on a screen. PIXEL the word is the words picture and element. The pixel or the picture element is the smallest , smallest, smallest unit of any image.

What is the smallest, smallest, smallest unit of a pixel?

The unit is not measurement given to an image from the size of the image taken or processed of saved as on a computer, the unit is just basically the smallest part of an image. A pixel.

FOR EXAMPLE?

You have just taken a picture on a camera.

The picture is loaded onto a computer.

You see the image?

You zoom in?

The image now looks like great big square blocks?

The square blocks are the images units. The units contains colours that make up the image. The pixels are set in pixels per inch (PPI).

It is important to recognize that pixels are not a measure of size, though often the term is used as though they are. Many digital cameras, for example, give a measure of pixels-per-inch (PPI), which they embed in the image files created. Users then see this measurement and assume that pixels have a real size which uniformly holds true.

What are Vector Images?

Vector images are images that are loaded on a computer in mathematical equations. The Equations look at the images lines, points and curves, basically all the images features that are loaded on a computer screen. Vector images are illustrations of images represented on pixels. A vector cannot lose definition when the image is being re sized. The image can transform freely on a document or application allowing the image to keep true size.

What is the difference then?

The difference between a raster image and vector image is pure and simply that raster cannot be transformed from size range without losing quality in the image. A Raster image shows the pixels of the image on the screen in any format. Whereas the vector images only show files that are saved as a vector image. When you understand the limitations of each form of technology you will have better advantages of using Vector and Raster images.

Look at the quality in difference

Raster Left image (Blown up image)
Vector Image Right
In computer graphics, color depth or bit depth is the number of bits used to represent the color of a single pixel in a bitmapped image or video frame buffer. This concept is also known as bits per pixel (bpp), particularly when specified along with the number of bits used. Higher color depth gives a broader range of distinct colors.
Color depth is only one aspect of color representation (formally, the gamut: which colors can be expressed), expressing how finely levels of color can be expressed (formally, gamut depth); the other aspect is how broad a range of colors can be expressed. The RGB color model, as used below, cannot express many colors, notably saturated colors such as yellow. Thus, the issue of color representation is not simply "sufficient color depth" but also "broad enough gamut".

Color Space Fundamentals

Computer monitors emit color as RGB (red, green, blue) light. Although all colors of the visible spectrum can be produced by merging red, green and blue light, monitors are capable of displaying only a limited gamut (i.e., range) of the visible spectrum.

Whereas monitors emit light, inked paper absorbs or reflects specific wavelengths. Cyan, magenta and yellow pigments serve as filters, subtracting varying degrees of red, green and blue from white light to produce a selective gamut of spectral colors. Like monitors, printing inks also produce a color gamut that is only a subset of the visible spectrum, although the range is not the same for both. Consequently, the same art displayed on a computer monitor may not match to that printed in a publication. Also, because printing processes such as offset lithography use CMYK (cyan, magenta, yellow, black) inks, digital art must be converted to CMYK color for print. Many printers now prefer digital art files be supplied in the RGB color space with ICC profiles attached. Images can then be converted to the CMYK color space by the printer using color management methods that honor profiles if present; this helps preserve the best possible detail and vibrancy.

 Color Space Fundamentals

Computer monitors emit color as RGB (red, green, blue) light. Although all colors of the visible spectrum can be produced by merging red, green and blue light, monitors are capable of displaying only a limited gamut (i.e., range) of the visible spectrum.

Whereas monitors emit light, inked paper absorbs or reflects specific wavelengths. Cyan, magenta and yellow pigments serve as filters, subtracting varying degrees of red, green and blue from white light to produce a selective gamut of spectral colors. Like monitors, printing inks also produce a color gamut that is only a subset of the visible spectrum, although the range is not the same for both. Consequently, the same art displayed on a computer monitor may not match to that printed in a publication. Also, because printing processes such as offset lithography use CMYK (cyan, magenta, yellow, black) inks, digital art must be converted to CMYK color for print. Many printers now prefer digital art files be supplied in the RGB color space with ICC profiles attached. Images can then be converted to the CMYK color space by the printer using color management methods that honor profiles if present; this helps preserve the best possible detail and vibrancy.