Optimizing Pixel Graphics for Print

Pixel graphics are multicolored images or photos composed of individual pixels (picture elements). The pixels are arranged in a grid, hence the term "grid graphics" (sometimes called "raster graphics"). Each pixel is assigned color information, the sum of which produces the picture. With Spreadshirt, pixel graphics serve as a template for digital printing. So that we can achieve the best possible result in printing with your graphics, please bear in mind the following tips:

Requirements for your pixel design

  • PNG, JPG, BMP or GIF file format
  • Maximum file size 10 MB
  • Image resolution at least 200 dpi
  • Maximum size 4000 x 4000 pixels
  • Design is isolated

Optimizing image resolution

What’s in your image?

Photos or graphics in PNG, JPG, GIF or BMP formats are made up of pixels (picture elements). The pixels are arranged in a grid and each one is assigned a color. The number of pixels (in width and height) also later determines the size of the print.

With us so far? Ok, good. So, we print textiles at 200 dpi. The abbreviation dpi stands for dots per inch. This provides information on the density of the picture elements. A graphic that is 1000 pixels wide, for example, produces a design 5 inches wide when printed at 200 dpi. A 2000 pixel-wide graphic produces a 10 inch-wide design, etc.

If you’ve ever tried to set a small image as your desktop background or zoom in on a poor-quality smartphone photo, then you know what happens when an image doesn’t have enough pixels. A design with a low pixel width or height (for example, 800 x 600 pixels) can’t be easily enlarged without loss of quality (for example to 4.7 x 4 inches or more). Because of the "missing" pixels, the print would probably look blurry and out of focus. So make sure to only upload designs with sufficient resolution and number of pixels to avoid that blurry effect. We recommend 200 dpi and a maximum of 4000 x 4000 pixels, so as not to exceed the maximum file size of 10 MB.

If the resolution is too low, the pixels will be clearly visible.

Designs without background

Printing photos on T-shirts is extremely popular. Show photos to their best advantage and remove disturbing elements in the background – i.e. have the actual design without a distracting background. It is not enough to simply make the background white, because the white area will show in the print. It will be visible on both colored and white products. The background of an image needs to be transparent so that our printers can ignore it. That's why it's important to save your cropped image as a PNG.

Design with background vs. cropped design.

No color transitions with transparencies

To make sure that your design can shine on colored products in its full brilliant glory, our printers spray a white top coat on the product before printing. Your actual design will then be printed on this layer. This is why your design must not contain any transparency transitions, meaning color transitions from transparent to opaque. Why is this? In the semi-transparent areas, not only the product color but also the white layer would shine through. Adjustment tip for advanced users: To create an effect similar to transparency transitions, use raster and halftone effects in your graphics program, such as "dissolve" or "dither”.

Consider color differences in the CMYK and RGB mode

On a monitor screen, colors often appear brighter than on the printed shirt. To make the colors of your printed T-shirt look as intense as on the monitor, try the following:

  • Increase the brightness of your design. The printed product will never come out as brightly as the same image on the monitor. Please remember, that the monitor has its own light source whereas the print only reflects the light.
  • Increase the contrast and saturation of your graphics to a very high degree. What may look a bit ”too much” on the screen will look just right in print.
  • Always upload your graphics in RGB mode. Our software systems work with this color scheme, and that's why smaller color deviations are to be expected with RGB files when compared to CMYK files.

From left to right: Perfect – design too dark – contrast too low – saturation too low.