Vector versus Raster Images

The sign industry has evolved over the past 10 years with the introduction of digital printers. These days you can have logos with blends, beveled edges, photos, just about any kind of image printed and used for the purpose of signs.

Most digital printers are capable of printing 1440 x 1440 dpi (dots per inch) which is superior quality. However, if you try printing a low resolution GIF or JPG, the image will more than likely print poorly. Why you ask? These files are what we class as RASTER IMAGES which are made up of pixels (dots).

Sadly when you try and enlarge a raster file, you’re simply enlarging the pixels which become blurry, and eventually, hard to make out what you’re really looking at.

Sample 1 – This is a great quality photo taken at high resolution.

Sample 2 – Enlarge the photo beyond the original size and you’ll start to notice blurring and worsening pixel size.

Sample 3 – This shows how the pixels begin to blur to an unbearable level.

How do you avoid pixelation?

1. Start with a high resolution photo / image in the first place.
2. You can always reduce a large file without effecting the pixels, but avoid doing the reverse.

Let’s have a look at VECTOR IMAGES.

Vector files are virtually lines as illustrated in this image.

Sadly vector artwork can’t be used all the time, but it’s ideal for text, shapes, cartoon images, clipart etc. Vector files can be enlarged or shrunk in size without effecting the quality of the image. They do not use pixels.

You can see, it doesn’t matter how close we zoom in on the file, you won’t see pixels.

Vector files can only be created using specialised programs including Adobe Illustrator, Signlab, Corel Draw and numerous other equally good programs. They’re generally programs only associated with business or industry who rely on high quality files.

Here’s some tips to consider before heading to your printer or signwriter.

• Ensure you use high resolution images for any signage or printing.
• Ask for the advice of your graphic designer as to whether the file will print clearly and if they say ‘no’, get a photo that will. It will be worth the effort.