One of the most amazing aspects of digital graphic design is the ability to create stunning effects like slowly disappearing shadows or clouds with bolts of lightening coming out of them. Both of these effects (drop shadows and glow or haze) can easily be created in most professional graphic design programs like Gimp and Photoshop, with a few simple clicks of a button.
However, just because the artwork looks great in your artwork file and even in the online mockup, you likely will not get the result you are looking for when you go to print the image digitally. This is especially true if you are printing on any dark colored garment (printing on white garments are far more forgiving). Read on to find out why!
It is NOT recommended to use effects like glow or drop shadow or any other effect that uses pixels with opacity less than 100% with a transparent background. These effects will likely not print as you expect them to on non-white garments.
In order to get great results with direct to garment printing, not only do you need some solid graphic designs skills, it also helps to understand exactly how the printer works to construct your prints. Understanding key principles about how direct to garment printers work will help you design artwork files that are sure to get great results.
How Direct To Garment Printers Print Colors
When printing your artwork on colored garments, direct to garment colors will first print a pass of white ink. Then, in a second pass, the printer will print colors directly on top of a the white ink. This is done, to ensure the colors are visible and vibrant for your prints. If a white undercoat is not printed, then the colors will immediately mix with the colors of the base garment and not be "true" to the file you provided.
So what does this mean for cloud effects, shadowing, etc?
Why Glows, Shadows, and less than 100% opaque pixels don't print as you expect
In any file that has less than 100% opacity on pixels (glows, shadows, etc), you will get an overwhelmingly "white" instead of a beautifully nuanced effect you are looking for. Here's why;
As we noted before, the direct to garment printer will print a white underbase on any pixel in your file that has a color value associated to it. So while the electric blue of a lightening strike in your artwork ranging from 1% opacity to 99% opacity looks amazing in your file, direct to garment printers will interpret all of those pixels as requiring a white under base, which will create the cloud of white. Next, the printer will attempt to print an exceptionally "light" version of your less than 100% opaque pixels, resulting in a mostly white blob, that doesn't quite give your lightening strike the effect you were hoping for.
Example of pixels at less than 100% opacity. Notice how you can see the background coming through. Files with these effects may not print as you expect them
As you can see the less than 100% opaque pixels appear white when printed
Ok, so how can you fix this and get great prints?
How to make sure your artwork will print great!
The best news about DTG printing is that you have a tremendous amount of control within the artwork file you provide for printing. Follow these simple rules to get great results.
1. Make sure all pixels are 100% opacity. The easiest way to achieve this is to add a new layer to your artwork (black or white typically works well), then merge the two layers together. This will ensure that any transparent pixels in your artwork are now 100% opacity. You can also crop out empty pixels from the background layer if you want to include some transparency in your file.
2. To achieve good results with gradients or to achieve shadowing effects, we recommend using half tones to create a blending of colors, instead of changes in opacity. This will give you optical blending while still still optimizing your DTG printing.
This is an example of a file that uses half tones to create a blending effect
Test print with halftones shows that colors are well managed and white "clouding" is minimalized.