The Tribune

Whether you are a newcomer, a student or just in need of a refresher, graphic design is littered with jargon and terms you may not be familiar with. So here are a few key terms all graphic artists should know when printing, re-sizing, sharpening and detailing images.

Raster images and Vector images

Vector-based images are made of points, while raster images are made of pixels. Raster images (sometimes referred to as bitmap images) are made up of thousands of pixels, which determine the colour and form of an image.

Photos are raster images. Photoshop is the most common raster editor, enabling you to manipulate the colour and other properties of the pixels. But, because raster images are made up of a finite amount of pixels, re-sizing can be tricky.

If you make a raster image into a larger dimension via Photoshop, the software has to make up data in order to add the size. This results in loss of quality.

Vector images

Vector-based images (such as those created in Adobe Illustrator) are made up of points, each of which has a defined X and Y coordinate. These points join paths to form shapes, and inside these shapes you can add colour fills.

Because everything is generated around this, vectors can be resized to any size without loss of quality.

In recent times, Illustrator has progressed so much that vector graphics have become incredibly complex, and you can now add gradients, complex shapes and more to create highly detailed, scalable vector images.

Since vectors can be resized, they are often used for creating logos and other graphics that need to go across many different productions (from leaflet to billboard, for instance).

CMYK and RGB

CMYK is the standard colour mode for sending documents, be it magazines, newspapers, flyers, brochures, annual reports and so on to the printers. It stands for Cyan, Magenta, Yellow and Key (or black). The colour black is referred to as ‘key’ because, in four-colour printing, cyan, magenta and yellow printing plates are carefully keyed, or aligned, with the key of the black key plate.

When you send a job to the press, cyan, magenta, yellow and black plates are made (on a traditional press) and then aligned to print on paper. You can add Pantone, or fifth colours, which are created as separate plates.

When working in Photoshop or Illustrator, you have the option to set your document’s colour mode as CMYK or RGB (red, green, and blue - for screen output. These two are the ones you really need to know about.

Because CMYK has a more limited colour gamut than RGB, which is essentially what the eye sees and how screens output, you can experience a loss of colour when converting from RGB to CMYK in these applications.

DPI and PPI

Resolution is another key term that is often confused, but always remember: The more dots per inch, the better quality the printed image will be. There are two main acronyms used when dealing with resolution: DPI and PPI.

The former is only of concern when you are creating work for printed output. It stands for ‘Dots per Inch’, and refers to the number of dots per inch on a printed page. Generally, the more dots per inch, the better quality the image - and 300DPI is the standard for printing images.

PPI refers to ‘Pixels Per Inch’ and, as you would expect, is the number of pixels per inch in your image. If you resize an image in Photoshop, making it larger, you will increase the number of pixels per inch (with Photoshop making up the data) and lose quality.

Whenever you are in the process of printing, bear in mind that the question of resolutions only applies to raster graphics, because vectors do not work in pixels. Until we meet again, fill your life with memories as opposed to regrets. Enjoy life and stay on top of your game.

• NB: The columnist welcomes feedback at deedee21bastian@gmail.com

ABOUT THE COLUMNIST: Deidre Marie Bastian is a professionally trained graphic designer/marketing coordinator with qualifications of M.Sc., B.Sc., A.Sc. She has trained at institutions such as: Miami Lakes Technical, Success Training College, College of the Bahamas, Nova South Eastern University, Learning Tree International, Langevine International and Synergy Bahamas.