Category Archives: design resources

Gradients and Halftones in Screen Printing

There’s some good conversation on Blake’s post about how to take your t-shirt artwork from good to great.

Jake asked: “What is the best way to blend colors using half-tone patterns that will translate well to screen-printing? Any common mistakes or things designers should be aware of?”

Well Jake, here’s the (really long) answer to that.

Let’s start with a brief explanation of what exactly halftones are:

Basically, halftones are regular patterns of tiny shapes (dots, ellipses, squares are common) that taper out to create the appearance of a color fading (or graduating) to white or another color at the edges.

Halftone

Take a gradient (like the above left) and render it as a halftone pattern, zoom in a bunch, and it would look something like the above right.

When a screen printer outputs a graphic that contains gradients onto films (which are used to burn screens – which is what the ink goes in), what they’re really outputting are these halftones. If you look closely at a screen printed tee that has gradients, you can actually make out these patterns:

upclose

But seen from a distance, it makes a perfect blend. You can see it best on shirts that only have a few colors and are especially ones printed on white:

zoom

Printers can adjust the angle, frequency and shape of these dots to increase or decrease the dot size of the halftones. Larger dots = more space in between them, more visible gradient appearance; Smaller dots = less space between them, tighter, smoother gradient appearance.

A lot of this is technical stuff that you never need to worry about as a designer (your screen printing will do all the work with setting up the correct halftones to make your gradients print well) but you can make their life easier by prepping your artwork correctly and understanding a little bit about the process.

Here’s some things you should know about printing gradients:

  • Understand Mesh Size
    The screens used for printing come in different mesh sizes ranging anywhere from 40 to 230. The lower the mesh size, the larger the holes in the screen and the more ink is pushed through to the shirt.Gradients require the opposite end of the spectrum: high meshes that don’t let a lot of ink through (otherwise the little dots all blur together and look like a blob). Not all screen printers have these higher mesh screens required to do gradients, which is why many of them don’t.
  • Be aware of the trade-offs of mixing large solid areas and gradients in the same color
    If you have a color in your design that covers a large of area andhas gradients, the printer is suddenly faced a dilemma. Do they chose the high mesh screen that will print the gradient without blurring (but lay down less ink in the places the color has large coverage)? Or do they chose a lower mesh that will give good coverage to the large areas but potentially blur the halftones.Generally, there’s a decent in-between option, but most printers will opt to preserve the halftones. So you may notice some lighter/sketchy coverage on the large solids.
  • Halftones and Underbases don’t mix well
    An underbase is used when printing on dark shirts to provide, you guessed it, a base for the design to keep the colors from getting absorbed into the fibers of the shirt, and preserve vibrancy. It’s usually a white or light gray, and underlays the entire design (or most of it, depending on the color of the shirt and colors of ink being used). Because you’re covering such a wide area with ink, underbases are generally on a lower mesh screen, which almost never agrees well with gradients… which brings me to our next item:
  • Sometimes your solids and gradients can (and should) be printed separately This generally adds to the cost of printing your design (because most printers charge per screen), but it can be a good solution if you have issues with coverage, or a design that’s going to have a white underbase and gradients that fade from color to the shirt.The solids are outputted on one screen with a lower mesh, and the gradients are printed with the required higher mesh.

And here’s some things you should do with your artwork to make outputting your gradients easier:

  • If you’re working in a vector program, make sure all your colors (including gradients) are in PANTONE colors.
    This includes using a PANTONE white for gradients that go from a color to white. When prepping your artwork, the printer needs to convert all RGB/CYMK colors to PANTONE for output, and they’ll hate you less if they don’t need to go through and replace colors in the 200 objects of your design that have gradients.
  • Don’t flatten your image if you’re designing in Photoshop or another bitmap editor
    This is good advice for any design regardless of whether it includes gradients or not, but it’s significantly easier to split apart the colors of a gradient when they haven’t been combined together.
  • And finally… don’t try and use gradients on highly detailed, small areas of your design
    Remember the dots from the up close picture of a halftone? These dots can only go so small, and in smaller areas of your design it can be hard to concentrate enough of them to visually see any time of transition.
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How to take your T-Shirt Artwork from Good to Great

This post is by one of our guest authors, Blake from You Design It. Read more about Blake at the end of his article.

Have you ever spent countless hours creating a masterpiece for t-shirt printing only to receive bad news back from the printer? You have probably heard something to the effect of “the resolution is bad” or “we can’t separate the colors” or even the silly response of “we can print this but it’s not going to look good”. Now why would you want someone to print something, if it isn’t going to look good?

We want to take this opportunity to identify some of the problem areas in a t-shirt design, and how much better the artwork can look for print. We’re actually going to do this with a real world example of a very advanced t-shirt design that was submitted to us and how it looked once we cleaned it up. With the money spent on custom T-shirts, I think we can all agree that the design needs to look the very best it can.

First let’s begin with the original image that was submitted to us for print:

At first glance it looks great and we were very impressed with the artist’s skills. Once we took a little closer look, we noticed that there were a few rough edges and some shading that would not translate well into t-shirt printing. Here are three closer images on areas that needed some improvement because of the usage of glows, shading, and an overall lower resolution.

Need Improvements

Need Improvements

Need Improvements

The way we solve these problem areas is by converting the jpeg or raster image into a vector format. This is a process that needs to be explained in a different/longer blog post because of the complexity. For now though, we just want to help with the awareness in identifying areas needing improvement.

Here is the final artwork after being converted to a vector format:

Cleaned up Version

And here are those three close-up images with much cleaner lines, less shading, and more solid colors.

Cleaned up Version

Cleaned up Version

Cleaned up Version

Ultimately, printing the t-shirts from a vector format made them go from good to the very best they could be. Don’t just settle for good after you have put so much into your project.

*Disclaimer: T-shirts can be printed from raster images in 4-color process for screen printing or they can be printed digitally. This post is intended for specific situations and does not cover all t-shirt design scenarios.

About Blake Poutra at You Design It
You Design It
Blake Poutra has been in the t-shirt printing industry for 10 years and learns new tips and techniques every day. He works for You Design It where they print thousands of t-shirts a day and he rides an electric scooter to work. 🙂 [editor’s note: lucky bastard!]

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