At Shadow Graphic Images, we pride ourselves in quality screen printing. Screen printed shirts are great for advertising, events, schools, sports teams, clothing lines, you name it! Your branding is important and we want to help you succeed!

Vector v Raster (Bitmap) for Screen Printing


Often, when our customers begin the process of submitting designs for printing, we find that there is confusion regarding the type of art that we need to receive from them. The confusion seems to center around Vector graphics files. Most people who are not professional graphic designers do not know what Vector art is. Indeed, there are even some people working as graphic designers, who do not know what vector graphics are.

We hope, in the following section, to bridge that gap, at least a little bit. We will describe, as best we can, what vector art is, and how to recognize it.

 What Is Vector Art?

Vector art is created using vector illustration software programs, such as Adobe Illustrator or Corel Draw. These programs use mathematic equations and geometric primitives (points, lines, and shapes) to create art that is clean, camera ready, and can be scaled infinitely, without any loss of quality or fidelity.

In the following graphic, we will show you the difference between Vector art and the other, more common type of computer graphic, Raster art:
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You’ll notice how, in the Raster art file, the edges of the art become distorted when the picture is enlarged. You’ll also notice how there are hundreds of shades of red in the Raster file, but only one shade of red in the Vector file.

Raster Graphics, such as photographs, and graphics files created in Adobe Photoshop, Paint Shop Pro, and other Raster editing programs, can be used for some screenprinting applications, such as printing one-color pen and ink drawings. But in most cases, especially with art such as logos, we will need Vector art to achieve the proper print.


 Is My Art Vector?

How can you tell if your art is Vector Art? One way is by the file type. Vector art is usually created in Adobe Illustrator, and is commonly saved with certain file extensions. The four most common Vector file extensions are .ai, .pdf, .eps and.svg.

However, just because a file is saved in one of these formats, does not mean that it is truly vector art. Sometimes, people open raster files in Adobe Illustrator, and re-save the file in a vector format, without recreating the art using the vector editing tools. Only art originally created in a vector editing program, such as Adobe Illustrator, is truly vector art.

So, how do you really know if your art file is a vector art file? The only way to know for sure is to open the file, and check to make sure that it was created as vector art. If you have a vector editing program, open your art file, and use the selection tool on an area within the art. You might see something like this:



See the nodes surrounding the letterform? Those are vector editing nodes. If you see those, congratulations! You have vector art.

Easy enough, if you have the proper software. But most people do not own a copy of a vector editing program. In which case, you will need to find someone who does, and get them to check the file for you. We provide this service, free of charge. Use the contact form at the bottom of the page to get in touch with us if you need help.


 My Art Isn’t Vector! What Now?

The file that you have might not be the only one out there. If you had a professional designer create your art, contact them, and ask for the vector files. If you work in a large company, contact your company’s marketing department or design department.

If, after all of this, you discover that you have a non-vector art file, and you need vector art, there’s only one thing to do:Hire a graphic designer to re-create your design as vector art.

When hiring a designer, make sure that they will provide the art in both vector and raster formats. If they are unable to do so, hire a designer that can.
We hope that we have demystified vector art a little bit. If you have any questions, or would like a free art consultation, please feel free to call us at 251-986-5010, or drop by the shop in person. We’re always happy to help.
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What is an Underbase and why it is required for Screen Printing?

What is an Underbase?

An underbase is a layer of ink (generally white or other light color) that is printed as a “base" on a dark shirt for other colors to sit on. This gives the top colors more brilliance. Since the underbase is generally a high opacity ink, it is flash-cured before the top colors are printed over it. Not only does underbasing slow production, but it is often an extra color that the customer did not plan on – or one that sales did not get enough money for. Underbases are also called an underlay (very common) or a mask (not very common).

Why use an underbase?

Although you could print each color as a high opacity ink and flash after each color, an underbase allows the print to have a bright look yet be soft to the touch because the underbase is printed through lower mesh counts and the top colors very high mesh counts.

How can I save money and not have to pay extra for an underbase?

If you a have a multiple color design and white is one of the colors of the design that we will be printing. We can use that white to make the underbase and you will not have to pay for an underbase. However if you have a multiple color design and white isn’t one of the colors we will be printing then we will have to put an underbase under the other colors and you will then have to pay for an underbase. We will let you know when you send us your design.

Do I always have to have an underbase?

The answer is no. Depending on the design colors and the garment color choices you may not have to have an underbase. An example where an underbase may not be required. Black ink on light colored garments, White ink on dark colored garments as well as most prints on white shirts. If you are not sure send us your art and shirt color and we can tell you. Sometime we can suggest some color changes that will keep your print looking good and not require you to have an underbase.

Example of shirts with and without an underbase.

Both of the shirts in the picture are identical in color and ink choices. The red color on both shirts is the same ink. This shows what happens to your color if you don’t put an underbase. It darkens the color. In this example the customer wanted the red to be vibrant like the one with underbase.

This Picture shows the shirt with no underbase.

The red ink doesn’t look the same as what the customer wanted. The red ink darkened and isn’t very vibrant.



This Picture shows the shirt with an underbase.

The red is more vibrant and is exactly what the customer wanted.



So as you can see in this example the underbase brought the true red ink color out and made the shirt look vibrant. In the end the customer was happy.

I like to look at it like painting a black wall in your home. Everyone knows you can’t paint green over a black wall because the green color will not cover the black. So you must primer the wall first then paint the wall green. This is the same with screen printing. In this picture the customer was lucky and didn’t have to pay for an underbase because they already had a 2 color print and one of the colors was white.

Comments or questions are welcome.

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