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Rasterising is the process of turning vectors, text layers, layer effects or any other type of graphics into a simple bitmap image made of pixels. Raster graphics can be made from vectors and are a collection of coloured pixels that make up images.

Raster-based images have a defined pixel count, so making them larger will affect their visual quality. Vector-based images, on the other hand, are created with mathematical data that allow them to be displayed at any resolution and without a loss in quality.

Why rasterise an image?

Rasterising is not typically a bad thing, and the shift from a vector to pixel format is generally not noticed. The loss of perfect edges is not noticeable unless you zoom in or blow up the image. If you plan to create a large format print of the image, for example, the pixilation caused by rasterising may become noticeable. However, if the photo remains in a standard size digital format, rasterising will not have a noticeable impact. Ultimately, rasterising an image allows printers to separate colours cleanly, and ensures the print is just as clear and crisp as the design sent.

Is vector or raster better?

Vector-based graphics are more malleable than raster images, so they are much more versatile, flexible and easy to use. The most obvious advantage of vector images over raster graphics is that vector images are quickly and perfectly scalable. There is no upper or lower limit for sizing vector images.

Whether you are an aspiring Pixar animator or a graphics editor, I recommend keeping images in vector format until they need to be edited at the pixel level, in which case rasterising is the only option. Remember, once you have converted the layer you will not be able to go back and change the size or font. Think twice, and save copies of your work as you progress.

What is the difference between vector and raster images?

The main difference between vector and raster graphics is that raster graphics are composed of pixels, while vector graphics are composed of paths. A raster graphic, such as a gif or jpeg, is an array of pixels of various colours which, together, form an image.

Can raster images be converted to vector?

While it is possible to create a vector image (such as an EPS file) from a raster graphic (a JPEG image), an exact conversion is not possible. Some programs such as Macromedia Flash can create paths from raster graphics so that they can be manipulated as vector images.

What are raster images best used for?

Best use is simple web graphics such as web buttons, charts and icons. A TIF (or TIFF) is a large raster file. It has no loss in quality, and therefore is primarily used for images employed in printing. On the web, because of load time, you generally want to use smaller images such as JPG or PNG.

How to rasterise an image

The process used to rasterise layers in Photoshop is fairly simple. Rasterising a layer in Photoshop is the process of converting from a vector file to a pixel-based file. The process is sometimes required for certain tools to function properly. The vector-based format maintains perfect resolution on all borders, while the pixel-based version will lose that crisp, perfect edge.

There are a few ways to rasterise in Photoshop, but the easiest is to find the Layer tab on the top menu and then select “Rasterise”. From here, you will have a few options:

• “Vector Mask” leaves the fill layer as is, but converts the vector outline into a pixel layer

• ‘Fill Content’ leaves the vector mask as is, but converts the fill layer into pixels.

• “Shape” merges the vector mask and fill layer, and then converts them both into one pixel- based layer.

Is Photoshop vector or raster?

At the highest level, the major reason for using Illustrator over Photoshop is one of image formatting.. Illustrator is built to make vector images, while Photoshop outputs raster images.

When you are prepared to rasterise, make a duplicate of the layer and save the original vector version. This preserves the original along with the option to return to the vector format if the pixel version is substandard quality. Until we meet again, fill your life with memories rather than regrets. Enjoy life and stay on top of your game.

NB: Columnist welcomes feedback at deedee21bastian@gmail.com

ABOUT COLUMNIST: Deidre M Bastian is a professionally-trained graphic designer/marketing co-ordinator and certified life coach with qualifications of M.Sc., B.Sc., A.Sc. She has trained at institutions such as: Miami Lakes Technical Centre, Success Training College, College of The Bahamas, Nova Southeastern University, Learning Tree International, Langevine International and Synergy Bahamas.