Raster vs. Vector, it’s all about the scale

The raster versus vector graphics file types have confused the best of us over the years. In this post I’m going to explain the difference, explain why it is important to apparel decorators, and illustrate the main differentiator.

To start let’s look at the technical definitions.

Wikipedia Raster: In computer graphics, a raster graphics image, or bitmap, is a dot matrix data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium.
Wikipedia Vector: Vector graphics is the use of geometrical primitives such as points, lines, curves, and shapes or polygon(s), which are all based on mathematical expressions, to represent images in computer graphics. 

Wow! Those definitions are incredibly useless. Let’s try it in normal people English.

Vector: Graphics composed of geometric shapes that are infinitely scalable without loss of quality.
Raster: Graphics composed of a series of individual colored dots, or pixels. Scaling may cause loss of quality.

Most apparel decorators prefer to use vector files because scaling graphics is often required to achieve the desired effect. Vector art simply produces the best possible result for the customer. If raster art can be created at the final print size, so scaling is not required, it works just as well too.

The image below demonstrates the scaling results for each file type at four times scaling.

An additional reason that screen printers prefer vector art is that many of the fancy effects that are easily created in raster tools like Photoshop are difficult or impossible to screen print. Having vector files lowers the occurrences of printing issues and complications.

Vinyl cutters require vector files because the cutter has to follow a geometric pattern to cut the desired shape.

Let’s not totally discount raster. Direct-to-garment (DTG) printers produce raster output. So, as long as scaling isn’t an issue, raster is the preferred choice for DTG. That explains why photographs and highly stylized art is so stunning when printed using a direct-to-garment printer.

I’d love to hear about your experience and pain in working with raster and vector files. Leave a comment below.

One Comment to “Raster vs. Vector, it’s all about the scale”

  1. dottonedan 23 November 2012 at 5:21 pm #

    Hello,

    I appreciate the professionalism of this site and your offerings. I would like to add to or comment on the raster art. I work about 90% in raster. I specialize in color separations. The point where you mention that the special effects are difficult if not impossible needs some additional information. Services like mine, make this all possible. So when someone sends the printer a file that can’t be easily separated by the current skills of the shop, it’s best to send it out to someone that is capable. You want to reproduce the image as best as possible and also keep the printing in house.

    ALL files can be translated to garment to about 99% of the original art. We just need to factor in wether or not it’s feasible to send the job out. if it’s 6 colors and simulated process but only for 12 shirts, it’s not that feasible, although I have had that happen.

    Separation services can make a beginner look like a pro and at the same time, they learn a lot more in the process. For my services as an example, I can separate any effect in raster and it will look as good if not better or more accurate than DTG. Direct to garment has a place and it’s with small runs using multiple colors. Order over 144 shirts with multi color, probably should be jobbed out to a separator so you can print it in house. It’s faster and more cost effective at that point.

    Additionally, I would add that pertaining to file resolution, if you have a file that is at maximum print size at 300ppi rez, you can always (reduce the size) without losing any quality. Just uncheck (resample image). It’s not recommended to go up in size with a low rez file of less than 150ppi, If you do, consider te amount of increase. I do not increase a 150ppi file any more than 30% max. If your file is already at a high enough resolution like 300ppi, you can go up twice that size without issue. Just uncheck (resample image). It will keep your image intact at a printable resolution.

    Thanks for reading.
    Dan Campbell
    Dot-Tone-Designs


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