Understanding Computer Graphics

If you are in charge of designing anything at all for your church, like bulletins, web pages, flyers, posters, etc., here are some simple tips to help your project turn out great. Everybody loves to add a graphic or photo to make their design more pleasing to the eye and to better convey the message. However if you don't understand some basic things about graphics it is likely that your graphics will convey the wrong message and reduce the confidence of your reader.

With computers there are two types of graphics; vector and raster. The most common type of vector graphic is a font. Fonts are just mathematical described shapes that can be scaled almost infinitely. The most common type of raster graphic is a photograph. It is made up of tiny squares of colors in a horizontal and vertical grid.

Vector:
The great thing about vector graphics is that they are small in memory size compared to raster graphics and their size does not change substantially as they are enlarged. Technically they can be scaled to the size of the Empire State building and still look really sharp and clear. For this reason a logo should be created as a vector graphic, this way it can be small enough to fit on a business card and large enough to fill the side of your church bus and still look great.

The bad thing about vector graphics is they are not very good for creating continuos-tone images like photographs. They also tend to make things look more like drawings and struggle to have a natural look or textures.

Raster:
Raster images can look so natural that it is hard to tell that it was created on a computer. There is some software that can create paintings that the average person would have trouble telling it was not painted with a brush and paint. Unfortunately rasters can be very large and hard for a computer to work with. All vector grahics are converted to a raster graphic at the time of printing, therefore it is converted at the resolution of the printer. However the raster graphics resolution is set at creation and will show pixillation when enlarged.

No matter which graphic type you are using there are a couple of things you need to remember. First scale your raster graphics to the rights size. This is especially important for web pages. If you don't resize the graphic correctly it can slow down the loading of a web page so much that people may leave before they read your message. Web pages are display at 72 PPI. PPI stands for pixels per inche. Pixels are the name for the little squares that make up a raster image. So if you want a photo to be 4 inches wide you would need the photo to be 288 pixels. because 72 X 4 equals 288 pixels.


This photo is scaled incorrectly, because
the girl is sqeezed.
Here is a properly cropped photo

For printing you need your raster images to be between 200 PPI for ink-jet printers and up to 360 PPI for printing presses. There are exceptions to this so you may need to consult your printer. Printing at a low resoultion will result in a fuzzy, blurry or pixelated look. This becomes very appearent when a raster graphic from a web page is printed. This is because the 72 PPI web graphic falls way below the 200 PPI minimum. As a side note you will see and hear about images being described as DPI, but DPI is really for printers. DPI stands for dot per inch, which means how many dot of ink a printer can lay down within one inch square. PPI and DPI do not correlate directly. This is because one pixel maybe a dark maroon, which means for that one pixel the printer would have to print dots of cyan, magenta, yellow and black ink to make a maroon color.

Second, if there was one thing you got out of this short article it would be to crop your images. So many people take a photograph and resize it disproportionately to fit into a space they want to fill, but this causes the photo to distort. If people are in the picture it can make them look over weight or grotesquely thin. In either case your design starts to look like a fun house with crazy mirrors.

If you can't get your graphic to fit the space you desire then it is time to either crop or find a new graphic. Cropping is a talent in itself. It is a very important aspect of photography. Most graphics programs have a cropping feature. Go to the help menu for instruction.

I hope this has been of great help to you and that your next project will be your best project—bringing honor and glory to our Lord Jesus Christ.

Whatsoever thy hand findeth to do, do it with thy might; for there is no work, nor device, nor knowledge, nor wisdom, in the grave, whither thou goest. Ecclesiastes 9:10