What is a 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.

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.

The alternative to a raster image is a vector image, which uses a mathematical formula to draw a picture. A vector image defines points and the paths that connect them to form a digital representation of an image. Because mathematics can be easily scaled, a vector image can be enlarged but still have smooth edges. However, vector images are limited. They are most suitable for typography, line art, and illustrations. A raster image remains the best choice for a photograph or shaded drawing.

What Is a Raster Scan?

A raster scan is a method of constructing an image through the use of horizontal lines. The lines can be analog representations of the image, or they can be a sequence of pixels in which each dot represents a tiny rectangular area of the image. One of the primary applications of raster scan technology has been in traditional display devices such as televisions or computer monitors. Some computerized printers also use raster scan methods to construct images on paper. Most digital images files also are stored and reconstructed using raster scan techniques.

In a television or computer monitor, an image is constructed using raster scan technology by starting in the upper left-hand corner of the screen and drawing a horizontal line that ends on the right edge of the screen. The line returns to the left side, dropping a tiny amount downward, and draws the next line of the image. When the beam that is drawing the image reaches the bottom right corner of the screen, effectively indicating the whole image was rendered, it moves back to the upper left corner to start again, an action known as a vertical retrace. This process occurs dozens of times every second to create a smooth moving image.


Even though a raster scan is capable of producing a very realistic image, the actual process creates a minute amount of nearly unnoticeable distortion in the image. At the end of each horizontal line being drawn, the beam must return to the left-hand side of the screen, which is called blanking or horizontal retrace. This is accomplished most efficiently by actually drawing each visible line with a slight downward slope toward the bottom right of the screen. In this way, during the horizontal retrace, the beam moves back in an almost straight horizontal line. Although it is the fastest way to draw the image, it actually means a monitor using raster scan technology is drawing the image skewed at a very miniscule angle.

Computer software that saves images digitally uses a similar technique to encode information and subsequently to decompress it. A raster scan of the image starts in the upper left corner of the image and progresses in the same way toward the bottom right. Instead of saving an entire line of analog information, however, the image is converted into small rectangles called pixels that can be set to a single color. The collection of the pixels in horizontal lines forms the image not only in the file encoding, but also in computer memory when the image is displayed.

How Do I Choose the Best Professional Graphics Software?

Choosing the best professional graphics software can seem like a daunting task, but with a little patience and planning, you can easily find the right program for you. Check out all local and online retailers who carry graphics software and carefully compare each option. Price, performance, and features are all things you will need to take into consideration before making a final decision.

Professional graphics software generally has a lot more features than lower grade commercial software programs. This allows the professional designer to create more engaging graphics, as well as providing more options for editing and transforming existing visuals into eye-catching works of art. In order for a software application to meet your criteria, it is first necessary to determine what those needs are. If you are a professional designer who regularly works with high paying clients, then it may be well worth the expense to buy a top of the line software program. If you are only a part time designer or want to use professional graphics software for personal use, a slightly less sophisticated model may be in order.


Begin your search by checking out all professional graphics software at your local retail outlets. Talk to all salespeople and ask about each software's features and benefits. You may even wish to find out the makers of each software program to determine which ones have created other programs you have enjoyed. Be sure to make salespeople aware of your budget ahead to time to speed the process along.

Shopping online is another option. Not only can you often find professional graphics software for lower prices on the Internet, but there are also consumer tools that may come in very handy during the buying process. Most websites allow for consumer feedback. This means that below each listed software, customers who have purchased it can leave commentary on its performance and other important factors. This is sure to give you a more accurate look at what owning the software would be like.

Other things you may want to consider involve the company who makes the software as well as the retailer you purchase it from. What is the return policy? Is there any technical assistance available if you have any problems using the software? Can you install the software on multiple computers, and if so, how many? The answers to these questions may be of assistance to you while making a final buying decision.

Once you have chosen your software, follow the directions for installation and install the program to your computer. Try out every feature right away, even if you do not need or use some of them very often. This ensures that if there are any glitches in the software, you will discover them while you can still make a return.

What Are the Different Types of Car Graphics?

There are several common types of car graphics that are aimed toward adding visual artwork or information to the exterior of a vehicle. For example, bumper stickers are applied to the rear bumper of a car and often serve a purpose such as espousing the viewpoints of the driver. In addition, car wraps are normally paint or vinyl film applied to partially or entirely cover the vehicle in order to display an advertisement. Finally, car decals are often used to decorate a car while avoiding the permanence and hassle of painting.

Bumper stickers, perhaps the most commonly recognized form of car graphics, are typically displayed on the rear bumper of a vehicle. These stickers are usually meant to be readable by a car behind it or passersby, and are often political or comical in nature. For example, they may imply that the car behind is following too closely or make a brief argument for the viewpoints of the driver. Though bumper stickers are normally applied to the rear bumper of a car, they are sometimes applied to other locations on the vehicle or onto an object other than a vehicle.


Car wraps are kinds of car graphics used to advertise products or services by putting media about those products or services directly onto a vehicle. This type of advertisement is also applied to other types of vehicles, like buses, trains, and large trucks. Wraps are frequently painted directly onto vehicles but may also be made from removal vinyl. Some advertising companies are known to pay people to put car wraps on their vehicles and drive around certain areas or park at certain places at specific times. Individual business owners can also be observed utilizing car wraps on their own personal vehicles in order to raise awareness of their product or service.

Other car graphics are decals, which are used to add visual accents or flavor to a vehicle. These decals are often used as a non-permanent way to decorate a vehicle and are sometimes used in favor of paint or stenciling due because they are removable. Large decals might display yellow and orange flames across the sides of a car or along the top of the hood. Less extravagant car decals might, for example, display the insignia of where the car owner went to school. Other common themes of car decals include the symbols of sports teams, symbols representative of locations, as well as brand names or sayings.

What Is a Holographic Interface?

A holographic interface is a way to interact with electronics without coming into physical contact with the machine. Though the holographic interface was only developed in the 2010s, it is often compatible with contemporary computer systems and programs. The creation of the hologram is a relatively complex component of the interface, whereas the ability of the interface to recognize the commands of the user is achieved through the use of motion detectors, a technology that has been in use for decades.

In order to create a holographic interface, a special holographic projector is needed that can display a three dimensional image in space. The projector works like a monitor, but the images it displays are displayed about 6 inches (15 cm) in front of it. These images are only visible to people who are within a predetermined range, usually within a few feet (about a meter) of the screen and at a fairly direct angle to it. This range can be adjusted, depending on the intended use of the holographic interface. People standing outside of the viewing angle are unable to see the interface, which can add extra security to these devices.


To interact with the holographic interface, a person touches the holographic image just as they would a real object. Though there is nothing there, an infrared sensor detects what the user is touching and uses this information to send instructions to the electronic device. The controls on the holographic interface can be used in the same way as physical buttons, keyboards, a computer mouse, or a touch screen but do not require the physical manipulation of any object.

There are a number of practical applications for a holographic interface. One use for this technology is in areas that must be kept sterile, such as operating rooms. Doctors often use computers to control instruments and to make adjustments on various controls. In a sterile environment such as this, the doctor cannot easily switch between touching a non-sterile computer interface to touching sterile surgical instruments or the patient. Using a holographic interface, a doctor can use the computer and then continue with the surgery because there is no physical matter in the hologram that could contaminate the patient.

A holographic interface is also useful in situations where a traditional computer interface, such as a touch screen, is impractical. There is no glare on a hologram, which makes it easy to view in all different types of light. Pilots at high altitudes may be able to make use of these interfaces instead of computer screens, which can sometimes be difficult to read at altitude.

How Do I Become a Graphic Design Trainee?

There are several ways available to you to become a graphic design trainee. The most important is to acquire basic knowledge of styles of visual presentation as all graphic design revolves around presenting ideas and concepts visually. You develop a basic familiarity with computer aided design (CAD) as well, which will require you to learn how to use graphic design software. Though a trainee position is an entry level position, acquiring such a position will require you, at least, to demonstrate familiarity with the ideas, tools, and processes of the graphic design trade. You should also enroll in an art, design, or computer graphics modeling program at a community college or a four-year university to qualify to become a graphic design trainee.

Before you apply for any graphic design internship or trainee position, subscribe to several graphic design trade publications. This will give you a sense of the contemporary tastes and trends in graphic design, topics that may come up in your interviews. To become a graphic design trainee, you should have a way of expressing ideas and concepts visually. Though you do not need to be thoroughly versed in any particular techniques, you may be asked to demonstrate your ability to take written instructions and to demonstrate how you would convey that message visually.


To become a graphic design trainee, you must develop familiarity with computers and with the suite of software used to create designs. The industry standard is the Adobe® Creative Suite®, which includes Adobe® Photoshop®, Illustrator®, InDesign®, Dreamweaver®, Flash® and other programs. For pagination and other layout tasks, you may need to learn QuarkXPress® or the Microsoft Office® suite that contains Microsoft® Publisher. Many community colleges offer introductory courses in these programs, and there are numerous independent seminars that are given by design experts that can help you familiarize yourself with the basics of using them.

Acquire one or two freelance graphic design contracts, and develop a chapbook of your designs. It is perfectly acceptable for this chapbook to be rough and rudimentary, but simply having one will show your initiative and help you rise to the top of the pool of applicants for a graphic design trainee position. Be aware that most trainee and apprenticeship positions do not pay, though some may offer college credit toward the completion of your degree. It is important to be enrolled in a graphic design program while you search for a trainee position so that the employer understands that you are learning a wide variety of skills.

What are Raster Graphics?

Raster graphics are digital images represented by a matrix or grid of pixels commonly called a bitmap. Each pixel or dot displays a unique color and together all of these colored dots create an image. Every pixel in a bitmap is stored as one or more bits in computer memory. Raster graphics with a greater number of colors and pixels will require more bits and take up more memory. Typical file formats for raster graphics include .jpg, .gif, .tiff, and .bmp.

Since raster graphics are represented in a grid structure, the width and height are usually indicated by the number of rows and columns rather than a particular unit of measurement. The size of an image might be described as 640 x 480 meaning that there are 640 pixels in a row and 480 pixels in a column. The resolution or degree of sharpness present in an image is calculated by determining the number of pixels per inch (PPI) or dots per inch (DPI). A higher resolution raster graphic will have smaller pixels that result in a more detailed image. When raster graphics need to be displayed or printed at larger sizes, it is helpful to use a higher resolution so that the image does not appear grainy.


Black and white raster graphics contain only black and white pixels and each pixel requires just one bit in memory. A colored raster graphic requires additional bits because three values are necessary to represent each of the red, green, and blue components of the pixel. The color depth for an image is represented by the number of bits per pixel and as the color depth increases, more colors are available for display. An image with an 8-bit color depth would have 256 different colors available compared to an image with a 12-bit color depth that would allow for 4,096 colors. Graphics with increased color depth are more adept at displaying shading.

Raster graphics are only one of the two common graphic types used to digitally represent 2-D images. Vector graphics consist of points and paths and the mathematical relationships that connect them to create an image. A vector graphic is infinitely scalable in size, whereas a raster graphic is resolution dependent and changes in size will detrimentally affect the visual quality of the image. Vector graphics are often used for type work and line illustrations while raster graphics are most suitable for photographs and images with continuous tones and shading.