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Blog / Beginner's handbook / Your Guide on Preparing the Perfect Print File

Beginner's handbook

Everything You Need to Know to Prepare the Perfect Print File

Everything You Need to Know to Prepare the Perfect Print File
Marianna Zvaigzne

By Marianna Zvaigzne

12 min read

If you’re figuring out how to start a clothing brand, it’s essential to understand the critical role of print files in product creation. The success of your online store heavily relies on the quality of your products. This quality, in turn, depends on the print files you create. The better the quality of your print files and designs, the higher the overall quality of your products. 

Diligently working on your designs will minimize the risk of order delays caused by not meeting Printful’s requirements. Remember that each delayed order can lead to a dissatisfied customer, who may be frustrated by the wait for a product they eagerly anticipate.

The golden rule behind nailing your Printful print files is to follow the guidelines created by our in-house experts. To explain Printful’s make-or-break print file requirements in greater detail, we asked Printful’s Graphics Team for tips to help you make the perfect print file.

Print file terminology

Let’s lay the foundation here and get into some terminology. It’ll help you better grasp the rest of this blog and Printful’s print file guidelines.

Print size is the size of the image as it’ll come out printed on the product. It’s measured in inches or centimeters. It can vary from the digital image size (see below). 

Image file size is measured in bytes and shows how much space the image takes up on a disk or drive. The maximum image file size you can upload on Printful’s Design Maker is 200 MB.

Pixels are units of measurement for digital images you see on a screen.

Pixel dimensions express the total number of pixels along a digital image’s width (horizontal) and height (vertical).

Resolution represents the density of pixels or dots in an image. For digital images, the resolution is expressed in PPI—pixels per inch. For printed images, the resolution is expressed in DPI—dots per inch.

DPI (dots per inch) is a printing term. Digital devices display images in pixels, and printers print images in dots. DPI is calculated using your digital image’s pixel dimensions and digital image size.

The higher the DPI = the more the dots = the sharper the print.
The lower the DPI = the fewer the dots = the blurrier the print. 

To help you visualize the relation between dimensions and resolution, look at the three penguins below. The images have the same dimensions (width and height) but different resolutions (DPI).

So, which penguin looks the best? 
a penguin with different DPI

DPI makes a difference

Unless you’re an advocate of the lo-fi look, you’ll agree the best-looking penguin is the 150 DPI one on the right. And this is also the penguin that will look the best printed.

Now that terminology is out of the way, let’s get back to Printful print files. 

Guidelines for Printful print files

For the best results, always check the Printful guidelines and print file templates in the File guidelines tab on each product page. That way, you don’t have to worry about the correct file formats and DPIs—we’ve got it all figured out for you! 

file guidelines tab

The File guidelines tab is your friend

A good way of creating designs for print files with the correct dimensions and resolution is by using Printful print file templates, especially for all-over print (AOP) and embroidery products. For embroidery, the templates will help you figure out how thick your design elements would be, and for AOP, the templates will give you a better understanding of your design size and placement. 

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If you’re just getting started with creating print-on-demand designs, remember that the built-in tools in Printful’s Design Maker (Clipart, Text Tool, Quick Design, etc.) are a fail-proof way to make good print files because our team made them with quality in mind.

Some more good news: The Design Maker, where you upload your design and create your print file, will warn you when your image isn’t suitable for printing.

Onto the make-or-break guidelines. 

  • Accepted print file formats: PNG, JPEG.

  • Accepted embroidery file formats: PNG (JPG accepted, but not recommended: design elements in images of this format always have a background, which can make the design look bad, and JPG also unnecessarily increases the embroidery stitch count, making it easy to go beyond the limit).

  • Maximum size of the print area: It depends on the product you choose (e.g., the standard print area for t-shirts is 12″ × 16″, for 11 oz. mugs—9″ × 3.5″).

  • Print file resolution (DPI): Again, it depends on the product, but it should be at least 150 DPI and no higher than 300—going beyond 300 DPI won’t improve the print quality, just increase file size. Print files for smaller items, like mugs or personalized phone cases, need a DPI higher than 150 because those prints are small and often detailed. We recommend submitting designs for these products with a DPI of 300.

  • Color profile: The final version of your print file should be saved in the sRGB color profile sRGB IEC61966-2.1. You can set the color profile in your image editing software.  

Why sRGB and not CMYK?  sRGB has a broader, more vibrant color range (aka gamut) than CMYK. 

Our DTG printers work with an upgraded CMYK color space where we’ve added more ink colors, allowing us to achieve print colors that generally fall outside the CMYK color range. The closest color space to our upgraded CMYK is the sRGB IEC61966-2.1, so we recommend using that for print files.

Read also: Color Matching Guide for Print-on-Demand Products

  • Acceptable content: Your design has to follow Printful’s Acceptable Content Guidelines. If your design is hateful, illegal, or violates any intellectual property rights, our team may block it. You’ll still see the file in your order or File library, but you’ll receive a warning about your design being blocked, and we won’t print it.

Read also: Can I Print That? Copyright and Trademark 101

5 Printful print file mistakes and how to fix them

Now that you know what it takes to create a perfect print file, let’s look at some reasons that can cause your designs to come out in low quality and how to get past them.

1. You resized a low-quality image, lowering its DPI even more 

As a coffee fanatic, you wanted to create custom t-shirts with a moka pot design. You found a copyright-free design and uploaded it to the Design Maker.

Turns out the 335 × 410 px royalty-free image looks tiny in the 12″ × 16″ t-shirt print area. You decide to enlarge the image right there in the Design Maker.

As the image dimensions grow, the number of dots per inch shrinks. The DPI registers as 60—well below Printful’s recommended range of 150–300. What can you do?

bad-quality-print-file-example

Low quality image (left), the same image enlarged (right)

You have four options:

  1. Find a new, high-quality image of a moka pot that’s 150–300 DPI from the get-go

  2. Settle for a smaller image than you wanted 

  3. Turn your low-quality image into a vector image

  4. Use the image adjusted by Printful’s Smart Image Tool

The first option is self-explanatory, so let’s delve into options B, C, and D.

B. You settle for a smaller image than you wanted 

In the Design Maker, you reduce the image dimensions using the blue corners, so the dots of the image DPI come closer together, forming a smaller, yet crisper-looking moka pot. You admit it’s not ideal, but accept that it’ll do for what you had in mind. 

 a person wearing a white shirt

A bit sad, but might work as a pocket print!

 

C. You turn your low-quality image into a vector

If you have the time or the experience, you can recreate your low-quality moka pot as a vector using a vector editing program (Illustrator, Inkscape, Affinity Designer, etc.) or an online convertor.  Another option is to contact Printful’s Graphic Design Services for a helping hand.  

Vectors are graphics of points, lines, curves, and shapes based on math formulas. They’re cool because you can resize them without losing quality. In the design software mentioned, you can use image trace or pen tools to convert your low-quality graphic into a vector.

Once you have your vector, resize the image as needed for your design and export it as a PNG file. At this point, your vector file has become a raster image. After that, you can upload it to the Design Maker and continue designing. 

If you want to use stock vectors or other images for your designs, double-check that the content is not copyrighted and the image size and DPI are equal to or higher than what Printful recommends.

D. You use the image adjusted with Printful’s Smart Image Tool

What’s the Smart Image Tool, and how does it work?

It works with the help of Artificial Intelligence (AI). The AI we’re using has studied more than 10,000 images to predict how the image “information” (number of dots) behaves depending on the changes in image size.

If you want to enlarge an image with a DPI of 38–74, Printful’s Smart Image Tool can double the image size of the original without losing quality. 

In the case of the 60 DPI moka pot: 

  • The Smart Image Tool analyzes the image to see what information can be added to meet Printful’s minimum print requirements.   

  • The tool adds the missing information so that the “average” 60 DPI image becomes a 120 DPI “adjusted” version.

  • The adjusted moka pot is still below the recommended 150 DPI, but it meets Printful’s minimum print quality recommendations, and you can add the adjusted design to your store anyway.

 a screenshot of a computer

The Smart Image Tool in action

Remember that if your product design doesn’t meet the absolute minimum print requirements, the Design Maker won’t allow you to proceed. 

After the minimum requirements are met, though, the quality of your design is in your hands. That’s why we strongly suggest following Printful’s guidelines and choosing quality!

2. You made a DTG design with a background that shouldn’t be there 

Avoid adding a background color unless it’s a part of your design—this is especially important for the custom clothing designs you want printed using the direct-to-garment (DTG) technique. 

Learn More: DTG vs. Screen Printing: Choosing the Right Apparel Printing Method for You

Why? The printer will print all the colors it sees in the design. For the printer, a black background on a black garment does not equal transparency. 

So, if you create a DTG design with a black background on a black garment, be aware that you’ll be left with a grayish rectangle around your design. And it’ll be gray because prints on all non-white garments require a white underbase to help the colors stand out.

If you want the gray rectangle, that’s cool. But if you don’t, remove the background! You can use the Background Removal Tool in the Design Maker to remove the unnecessary background with just one click.

If you’re not sure if your design has a solid background, open the file in Photoshop, GIMP, or a similar image editing software. If the background is transparent, you’ll see the standard white-and-grey checkered background.

 white-vs-transparent-background

Design with a white background (left), design without a background (right)

3. You went crazy with transparency where you should’ve kept cool

Transparency as a design element works best for all-over print (AOP) and some other products, but it might not look good on DTG. 

The way transparent elements will come out in DTG depends on: 

  • How the design was created (e.g. you used feather brushes, semi-transparent layers, or similar effects, unaware that they’re a kind of transparency) 

  • The transparency level of the elements (100% transparent or semi-transparent) 

  • The color of the garment they’re printed on—whether the garment needs a white underbase

    • White garments = no white underbase, transparencies will print out fine

    • Non-white, light-colored garments = the white underbase will be difficult to notice but might shine through semi-transparent areas 

    • Dark-colored garments = the white underbase might be visible as small white speckles in semi-transparent areas 

Bottom line: keep the white underbase in mind when creating a DTG design, and consider whether or not a semi-transparent effect is what you want. Some designers like the effect of the white underbase showing through, so it’s a matter of taste! 

 a close up of a word

Here, the white underbase peeking through is a design decision

For all-over print (sweatpants, leggings, etc.) and sublimation (mugs, towels, etc.) products, transparent elements are OK to use because these printing techniques don’t call for a white underbase. For AOP, you may still want to fill the entire print area with solid shapes or colors as much as possible to avoid any blank white fabric showing. Unless, again, it’s a part of your design! 

a black and white map on a wall

AOP design example

Important note on phone cases: The components of your phone case designs should be at 0% or 100% transparency. We don’t recommend semi-transparencies because the final result will end up patchy.

If semi-transparencies are your thing, our Graphics Team recommends using the halftone effect instead. Halftone can be used on any kind of product, regardless of the printing process.

4. You didn’t remove your background properly 

Sometimes, a design looks fuzzy and low-quality, not because of poor DPI, but because the the background is removed incorrectly, leaving fuzzy edges. 

To avoid the fuzz, duplicate your final design with the transparent background multiple times in your image editing software. The little bits you missed will become more visible, and you can easily remove those unsightly edges.

Here’s what you might see after duplicating those layers: 

a close-up of a plant

The yellow arrows point to the fuzzy edges that need to be removed

5. You chose the wrong product for your print

Every product has a different texture and feel when printed.

That’s why, when selecting products for your designs, think about the print placement and design elements and whether your vision will work for this product. The rule of thumb is that patterns look good as all-over prints, photographs work well as posters, and typography designs are perfect for DTG and embroidery products.

If you’re selling apparel, remember that your designs will also look slightly different depending on the fabrics and fabric blends you print on.

For example, ink is more spread out and looks more faded on custom hoodies than t-shirts since hoodies are made from a thicker fabric. And due to the looser weave and combination of fabrics in tri-blends, DTG prints on tri-blend garments will have a vintage feel—the fabric will peep through the ink (watch out for tips like these in our product descriptions!). 

For some, that faded or vintage feel will be just what the doctor ordered, but for others, the print won’t look as imagined and will be perceived as poor quality. 

Read also: Guide to Cotton, Polyester, and Blended Fabrics

On your way to a perfect print file

If there’s one thing to remember from this blog post—stick to our print file guidelines. Knowing the terminology and Printful specs is a must if you want your orders to reach your customers without hiccups.

Ready to start designing? Head to Printful’s Design Maker and have a go! To make it more fun, check out this batch of typography designs you can use on Printful products— download below. 

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By Marianna Zvaigzne on Jan 24, 2024

Marianna Zvaigzne

Marianna Zvaigzne is the Head of Brand Language at Printful. With the help of her team, she’s pinning down what it means to “sound like Printful” and keeps Printful copywriters on their toes with animated editing sessions and writing workshops.

Marianna Zvaigzne is the Head of Brand Language at Printful. With the help of her team, she’s pinning down what it means to “sound like Printful” and keeps Printful copywriters on their toes with animated editing sessions and writing workshops.