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Everything you need to know to prepare the perfect printfile

By Julia Gifford - Reading time: 5 minutes

You’ve set up your store and you’re ready to start making your millions. But your entire business hinges on this one element – getting the printfile just right, so that your design can be displayed in its full glory that your customer will then bask in for the remainder of the lifetime of that garment.

And just when you think you nailed it, an order has come in and it goes to processing, and the unimaginable happens.

Your order’s put on HOLD! *gasp!*

Delaying the process, making you tinker with the design to get the right printfile.

I’m here to say you can get it right the first time!

I spoke to Printful’s graphics department to identify the most common errors with printfiles so that you can avoid them the first time around. We’ll be focusing on the most popular product – the DTG t-shirt.

Basics of graphics

To get started, here are some general rules of thumb to keep in mind when thinking about printfiles:

Max. printing area: 12×16 inches, with exceptions (see below).

DPI: Files have to be a minimum of 150 dpi (digital pixels per inch). If the dpi is higher, we can expand the image. Any lower and the image will be put on hold.

Best format for submitting files: .png

Worst format for submitting files: Adobe Illustrator files

File & image size is the top offender

One of the most common issues is with the size of either the file itself or the image you’re printing.

File size – the guidelines are key!

Printful t-shirt guidelines

Our graphics department says that 80% of hold issues could be solved if the printfile guidelines were followed. Why? Because there are exceptions to standard printing sizes for different models, cuts, and sizes of shirts. Here are some of the main transgressions in regard to file size exceptions:

The standard printing area men’s or unisex t-shirts is 12×16”, except for men’s XS, which is 10×12”.

The standard printing area for women’s t-shirts is 10×12”, except for women’s XL and larger, which is 12×16”.

Image quality and size

One of the most common issues is submitting a low-quality image, or an image that is too small to be qualitatively scaled up.

It might look fine on your screen when it’s only a few inches wide. However when the image is printed out on a real life t-shirt, the image also turns out to only be a few inches wide, meaning that it looks tiny in comparison to the life-sized t-shirt. Make sure the image you’re submitting is actual size, and that it reflects how big you actually want it on your garment.

If we do print out the unqualitative image, then it will be blurred, stretched and the edges will be pixelated. Generally not what high-quality online stores should be aiming for. All images should be submitted in no less than 150 dpi, however if your image has fine details, we suggest submitting the image at 300 dpi. So that in the case that you’re printing on dark garments, the white underbase won’t be visible.

However, keep in mind that even 300dpi does not guarantee a quality print, especially if the artwork is being printed on a dark garment – some of the white under-base may still be showing.

Tip: To quickly find out if your image is large enough to be printed in a good quality, upload it to the mockup generator and see if you can scale it to the desired size. If you want to print designs on shirts, you can do this even faster on our make your own shirt page.

The generator won't let you expand the image if it's too small to look qualitative.

The generator won’t let you expand the image if it’s too small to look qualitative.

Insufficient information leads to mistakes

Sometimes ambiguous orders come through. For example a design comes in at 6×6 inches (looks pretty small on a t-shirt), but in a high quality resolution (300 dpi). We don’t know if it should be printed in the 6×6 size, or if it should be expanded to full size (12” in width).

Note: with the resolution of 300dpi we can generally double the size of your image – this means it will be printed at 150dpi. However, if you want to keep the resolution at 300dpi, we suggest adjusting the actual file size. Communication is key – make sure to add mockup images and/or printing notes to get what you had intended.

File formatting for most accurate printing

We suggest submitting your printfiles in .png or .jpg. You should avoid PDF files, Illustrator files, and vector files as they don’t always convert properly (they end up printing hidden layers, or there can be missing fonts).

When going for a “glow” effect, don’t use the transparency function (aka lower the opacity) in photoshop. When it’s printed out, it will look like a bunch of polka dots due to the white underbase that’s applied underneath. On lighter garments, prints will come out a lot more concentrated that you might have intended since printers don’t always recognize transparencies and will print them as solid colors.

What it looks like when transparencies are printed

What it looks like when transparencies are printed – better to avoid this

To avoid this result, use half-toning to achieve the same “glow” effect.

Removing background images

Always remove the backgrounds. Even if you’re printing on a white garment and you think it’ll be fine if you leave the white background – don’t. Although your graphic is being printed on a white garment, the white background may actually cause the print to appear slightly muddy and blurry.

This is what happens when you leave the white background - the other colors get blurry

This is what happens when you leave the white background – the other colors get blurry

If you’re printing on black, then you’ll be left with a shiny rectangle around your design. That’s because these prints on dark garments require a white underbase, and as a result the printed black will be a different shade than the actual garment.

Orders frequently are put on hold because the backgrounds haven’t been completely removed. If any residue at all is left over, it will be visible when the shirt gets printed. The way we test this (and you can, too) is by opening the file in photoshop, duplicating the layer several times to make any residue show up.

We suggest you avoid solid backgrounds entirely. Unless it’s an express part of your design.

If you’re printing on a white t-shirt, we suggest removing any white elements in the design. That way white ink won’t be printed onto the design, and it will lead to a more crisp result. (same goes for black on black).

Making sure the colors on the screen match the printed colors

The colors you see on your screen are not always what you see when the garment has been printed. We suggest you order our RGB swatches onto the garments you want to print to see how they’ll show up in real life.

Pro tip: If you’re offering your design on many colors, it might get pricey ordering all of those swatches. You can get in touch with our design services, tell them which garment you want to print on and what design, and they’ll do the color matching for you to identify the correct values for the effect you’re going for.

Choosing the right garments for the best possible outcome

100% cotton shirts will always yield best results, with the exception of Gildan (remember what your mother always said – you get what you pay for).

Blended shirts will have a less vivid print, which is totally ok if you’re going for the “vintage” feel.

Different fabric blends yield different results

Different fabric blends yield different results

Tip: When printing on totes, we suggest you avoid white. Because of how the white underbase reacts with the fabric, the ink tends to scrape off. If white elements are an important part of your design, we can print the white under-base with your approval.

Conclusion

Keeping an eye out for these most common mistakes is a must – it’ll speed up the time your order goes from submission to shipping, and it’ll lead to happier customers (aka more moolah for you!). If there’s anything to remember from this post is – check the guidelines, accurately size your images, add mockups, and communicate what you want to the graphics department via print notes. And voila – you’re set to start making that uber cool independent online store that just happens to be raking in the cash.

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  1. Scott Larsen

    “To avoid this result, use half-toning to achieve the same “glow” effect.”

    You don’t draw any distinction between types of transparency: 100% clear, no ink goes on at all, vs somewhat clear as in that fade in your glow effect… The first is okay, the second is not.

    What “Line screen” should this halftone shoot for? It’s probably worth describing for people how exactly to create a halftone… and note that a halftone is very fine detail so 300dpi is a minimum resolution. If I were doing a halftone I would probably submit the art at 600 just to help keep the round dots round…

    1. Adam

      When creating your halftone: First off, I don’t work for these guys. I own my own graphics studio and silk screen shop. I do not use any post-script software printers or printing profiles. So I make all my separations individually.

      In Photoshop, after you’ve isolated the part of the image that you want to create halftoned (and of course it and the rest of your spot colors have been put together and scaled to the correct size for output), you want to take that isolated image; bring it into a new file; convert to grayscale (still at 300dpi) and then create your bitmap. You’ll see the first prompt in “Color Halftone” is dpi input and output. It will already recognize your 300dpi image and ask for you to enter the output resolution. I use 720dpi.

      From there, you set your LPI and frequency. There are many forums out there for the math you’d want to implement here for ideal results on an ideal screen mesh. Once bitmapping is complete. Convert back to grayscale; use the Magic Eraser tool (tolerance around 11 w/ Anti-ALias checked) on the white from the BG imagery. Zoom in closely and you’ll notice it lightened all the edges of your halftone dots. Duplicate the layer and merge. Problem solved and you now have a high-res workable , halftone file that can be printed as a composite print.

  2. Rana

    Does this go for posters also? I get why Illustrator files are bad for T-shirt printing but they’re the best for paper printing as far as I know. Can you please clarify? I’ve spent weeks preparing my print files in AI and really hope I can use them and not have to redo them in another format. Thanks!

    1. Julia Gifford Post author

      Hi Rana,

      Yes, this is ESPECIALLY true for posters. We’ve had damaged poster cases because of hidden Illustrator layers, that end up getting printed out. To avoid that potential issue, we suggest .png for the most consistently qualitative results.

      1. Rana

        Bummer. Ok thanks for the clarification!

        Side note – are there any plans to add a bulk delete feature for print files? Deleting them one by one is so time consuming and tedious.

  3. Scotch

    Agree with Rana – need a bulk delete feature for print files. Taking this a step further, a bulk edit feature. For example, used 12×16 template for XS men’s instead of 10×12. I’d like to edit that print file for only the XS products (20 designs x 7 colors), but doesn’t seem possible, other than manually editing every XS product.

  4. Kristin

    You have a rather funny typo in the short paragraph just above the skulls. Otherwise, extremely helpful. Thank you!

  5. marcus

    I`m just starting out with you guys and back “Scotch”, would want selective bulk editing as well.

      1. Jacki

        Hi Nora, I’ve a follow-up question… If the RGB is getting converted to the CMYK color space, then why not prefer files be made in CMYK to begin with? Also, I thought the Brother GT-3 printed in sRGB…has Printful changed its DTG printer type? Sorry, but I want to be sure I give the bright and pastel colors in my baby clothing designs the best chance they can get!

        1. Nora Inveiss

          Hi Jacki,

          No need to apologize! You’re correct, the Brother printers are programmed to use RGB color values. So to simplify the whole process, we ask for RGB files right off the bat, so we only convert to CMYK once (as opposed to CMYK-RGB-CMYK).

          1. John

            That wouldn’t be a problem. CMYK to RGB would do nothing because CMYK has less color options than so RGB, going from CMYK to RGB would not effect the image. going from RGB to CMYK loses colors so it conforms the image to the new palette.

  6. Raquel

    I’m new to this so I’m trying to upload files but they’re in AI and some of them look transparent on black tees. What am I doing wrong and do I need to just submit all in .png or .jpg. Should they have a transparent background or is white ok? I’m clueless as what program to use to get it how you guys want. Any help would be appreciated.

    1. Nora Inveiss

      Hi Raquel,

      You can find some helpful info in our printing guidelines here. Couple of quick tips:

      1. You should submit your files in either .png or .jpeg formats
      2. Your files should have a transparent background
      3. The program you use is up to you! We find that the majority of our customers use Photoshop.

  7. Damien samwell

    Hi Julia,

    I’ve had approx 16 test prints from your team so far and on sample where a block of colour is used on a dark tshirt the results are less than satisfactory. Prints appear speckled with white which I understand is part of the curing process. I have however had a grey circle print on black that does look good so it looks like it may be a quality control thing?

    Is there any way of printing solid blocks of colour without this happening? I was really really hoping that DTG printing could at least come a little bit closer to screenprint quality.

    Thanks
    Damien

  8. Muhammad

    Very helpful article enlightening all necessary details for quality printing. Thank you.

    I have a question regarding the colours of the t-shirts themselves not the designs. I would like to know what the RGB values are for the t-shirts themselves. Black and white ones are ok but let’s say the American Apparel Poly-Cotton pink colour for instance, what is the RGB value of that so I can add it to Photoshop during design as a background to simulate the t-shirt. Is there a way to know that?

    1. Nora Inveiss

      Hey Muhammed,

      There isn’t really a way to know the RGB color value of t-shirts. We’ve also tried looking up concrete color values for our products, and it was pretty much impossible to find.

  9. Darneshia

    I am completely new at this… How would I be able to make T-shirts or sweatshirts with just a saying on it? Let’s say,for thanksgiving a shirt said, “Thankful for my husband” I would have to have a background color for the writing? Is there a way I can just do writing with no background color? I do not always care for the big box around the words.

    What if I want to use “Thankful for my husband” but have it “Transparent where the lettering is outlined lets say Black with the letters being the color of the shirt?

    Thank you!

    1. Nora Inveiss

      Hi Darneshia! You can certainly create that design, with or without a background around, or with black lettering outlines.
      I recommend checking out our Photoshop tutorials. Or you can use our Design Services – fill out a form for a quote and our in-house designers will work with you one-on-one to get your designs print file ready.

  10. Darneshia

    Also, Am I able to take a silhouette off the internet and use that as a photo? Am I suppose to convert my finished product? Thank you

  11. Britt

    I’ve noticed that white ink prints out splotchy compared to black on a variety of products. Should I be adding a white base so that the white prints twice (is that even possible?) Is there a trick I should be following to improve the quality being printed?

    1. Nora Inveiss

      It could be the fabric of the shirt we’re printing on. We find that white results can vary depending on the fabric – you can read more about it here.

  12. john

    Hi
    Sorry i’m really late to this blog but i just wanted to know; is there a maximum file size for an image/file (in megabytes)?

  13. Kieran

    Hey Nora, can you tell me what is the poster papers base color.
    I usually remove the white paper background in Photoshop but need to know the base color and cannot find anything on your website, thanks in advance.

    1. Nora Inveiss

      Hey Kieran!

      Poster paper is white. If you want to leave the background and it’s pure RGB white, then the printer won’t recognize it and won’t print a background. It’s totally fine to remove the background if you prefer, but it’s up to you to do it cleanly. Hope this helps!

  14. Phyllis Jarrett

    Hi, I have a few files up now in png
    format for t shirts. …They are 300 dpi. If the size is larger than 12×16
    would I loose quality when sliding to a smaller size graphic to fit in the space on the mockup. Or should go in and change the graphics to 12×16 …crop them to the exact size ?

    1. Nora Inveiss

      Hey Phyllis,

      No, you won’t lost quality downsizing your image if it’s already at 300 dpi. You might run into problems increasing the image size, but if you’re making it smaller, you should be OK.

  15. AC West

    Can a screen print proof be read for a POD job?
    I own a design that I had done for me, and had a few samples done up by a screen printer years ago. The main print was done on the back, and a text screen done on the front.
    I want to just do the main print on the front.

    The timing is right to get these shirts off the ground in a new shop, but the designer no longer is in business, and I do not have separate files of just the design, but rather the design on 3 different colored shirts. Can these be used to create POD shirts, etc… or do I have to have someone redo them into just the design only?

    The problem is that the design uses different colors based on the shirt color. ie. Black text on white shirt…white text on red and blue shirts.

    I have had lots of good reports and reviews of using Printful…and since this is for a nonprofit startup, I wanted a company I could count on.

    Please let me know.

    ps: the pics I DO have are in .PSD formats.

    1. Nora Inveiss

      Thanks for commenting! You would need to create and submit print file for us to print; screen printing proofs won’t work.

      I suggest checking out our design services – you can show them your proofs and they can create design files that’ll work with our system.

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