2.01 Investigate graphic image design. Image Resolution 2.01 Investigate graphic image design.

Types of Images Clip Art – premade graphics that are available online and in many software packages; may be vector or raster. Photographs – raster images that contain millions of colors. Art Work – computer created drawings or paintings; may be raster or vector. Which type of image is appropriate? Select images that reflect the purpose and theme of the document. Use images to convey meaning and communicate, not to decorate. Teacher Note: The purpose of any business document is to convey a message. Students should make sure any images they use help them to convey their message. If the images do not make the message easier to understand, then they are confusing the message and should not be used.

The quality of an image is dependent upon two factors: Resolution Aspect Ratio Aspect Ratio Resolution

Image Resolution Resolution is the amount of detail (or data) stored for an image. The higher the resolution, the higher the level of detail in the image. Resolution is measured in PPI, or pixels per inch (the number of pixels contained in one inch). The higher the PPI, the more data that is stored and the better the quality. The higher the PPI, the larger the file size. Image editing software can be used to change the resolution of an image.

Image Output Methods Images can be viewed in two ways Monitors On a screen or monitor By printing it on paper Monitors The display resolution on monitors is also measured in PPI. Monitors are low resolution devices, most display 72 PPI. Printers Printers create output by placing ink or toner on paper. The resolution at which printers can print is measured in Dots Per Inch (DPI). Printers are high resolution devices in order to print images clearly without pixelation or blurriness. Teacher Note: Graphics displayed on a computer monitor can be set to 72 PPI because most monitors will only display 72 PPI. However, you need higher resolutions for printing images. 150 PPI is sufficient for desktop printing; 300 PPI for high quality printing. However, the larger the PPI, the larger the file size will become.

Match The Image Quality To The Delivery Method. Images that will be displayed on a monitor do not need a high resolution. Using a low resolution means smaller file sizes. Images with small file sizes load quicker. Images that will be printed need a higher resolution. Images with 150 PPI are sufficient for printing on most personal desktop printers. Images with 300 PPI are better for printing on more sophisticated printers and will produce higher-quality photographs.

Aspect Ratio Aspect Ratio – relationship of an object’s width to its height Aspect Ratio Resolution

What’s the answer? An image that is 1”x 1” has a resolution of 100 PPI What is the effect on the resolution of enlarging the image to 2”x 2”? What happens to the image quality? How will this image look when printed? Suppose an image has a resolution of 100 pixels per square inch and is 1 inch square. If you resize the image so that it is two inches square, it becomes 50 pixels per inch which reduces the resolution by half and also reduces the image quality. The same number of pixels is still in the image but the display area is larger. Therefore, you will see pixelation because each pixel in the image must cover a larger space on the screen.

Resizing a Raster Image A small image that is enlarged is easily distorted. Pixels are not added, just enlarged It is better to start with a large image and make it smaller File size will remain the same An image must be edited to reduce file size. You will notice that by stretching an image to make it larger, it gets fuzzy and distorted. This is because the computer just makes a really small square (pixel) of data larger or wider to cover more space on the computer screen. The end result is a distorted image. For this reason, it is easier to start with a large image and make it smaller than to try to make a small image larger than its original size. Remember: Compare the two images. If you were to compare the properties of both images, (by right clicking and scrolling down to properties on each image) you would see that it is the same image, but more importantly they have the same file size, although one is a lot bigger than the other.