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Getting the Upper Hand on Challenging Images

(November 2010) posted on Fri Nov 05, 2010

An exploration of the intricacies of different image types and output options.

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By Jared Smith

Before we can begin applying graphics to vehicles, we have to successfully get the image on the vinyl (or other media of choice). Of course, many technologies are out there that can get this accomplished – from roll-to-roll solvent printers to UV flatbeds and hybrids and much more, all with a dizzying array of specifications. No matter which of these print technologies you choose for your operation or a particular job, one factor remains constant: Some images are easier to print than others.
Let’s explore some of the intricacies of different image types and perhaps some of my observations will help you solve a few of your own shop’s output mysteries.

Raster vs. vector
In order to lay down an ink dot, you must first understand all of the factors that can affect where that dot lands, what color it will be, and what the final image will look like. This all begins with image file type. You can print from many image types, with the most common files for wide-format digital printing being EPS (.eps), TIFF (.tif), or portable Document Format (.PDF). Each of the file types handles the image content a little differently and it’s important to know the basic differences.

Raster file types such as TIFF, JPEG and GIF all store an image using square pixels, with each one having its own color value. This color value is made up of three numbers if RGB and four numbers if CMYK. As you can see, that’s a lot of information for one “dot” in an image. This concept allows these file types to have full, rich, and vastly wide color values. It also allows these file sizes to become enormous at high resolution or large scale. The issue with raster images is that their resolution is finite, and enlarging these files has a similar effect to placing them under a microscope – the farther you “zoom in,” the more you can see the shape of the pixel, which is square. Seeing 90-degree stair steps in a photograph is never the desired look.