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There are so many graphic design projects I’ve seen go horribly haywire because small errors were made at the start and they compounded as the project progressed. If you’re a graphic designer, you need to know the differences between print and digital, what makes good typography Stay True To Type: 7 Quick Guides That Tell You All About Typography Stay True To Type: 7 Quick Guides That Tell You All About Typography Learning about typography isn't only for designers. It’s for anyone who deals with the written word. Head to these seven places for quick no-effort primer classes on fonts and typefaces. Read More , the difference between raster and vector Increase Image Resolution: Convert Raster Images to Vector Increase Image Resolution: Convert Raster Images to Vector Read More  images, different color-mixing methods, and so much more, it can be overwhelming. But you have to start somewhere.

I’m going to teach you about what an image’s dots-per-inch (DPI) is for, because I want to save you from suffering the way I have.

Why Every Designer Needs to Know DPI

What kind of pain and suffering can I save you?

I once spent three hours redoing work on a 8-foot by 3-foot photo-collage banner because the person who started the file didn’t know how DPI and resolution worked. The photos in the collage weren’t saved at a high enough resolution to print at larger than a few inches each, and there weren’t nearly enough of them to span eight feet across.

It doesn’t even have to be someone else’s mistake. I’ve done this to myself: starting projects at a low resolution and then realizing later that it can’t be printed at the size I needed.

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What is DPI?

Let’s take some time to clear up some terms.

DPI stands for Dots Per Inch, and it’s a specification for a printer, meaning how many physical dots of ink will it print in a full square inch. Your home inkjet or laser printer will do alright at 200 dots per inch, but a professional printers typically won’t print at less than 300dpi or higher. That’s so that when you look at the final print-out, the image comes out crisp. If you use fewer dots, the image will come out blurry or seem pixelated.

For smooth detail, you want lots of small dots, tightly packed together, so the viewer can’t tell where where one dot ends and the next begins.

Here’s a visual demonstration of what I mean.

10-dots-dpi

PPI stands for Pixels Per Inch, which refers to how many squares of colored light a screen fits in one square inch. Standard displays have 72 pixels per inch. Some monitors have 90ppi, and those in Apple’s “Retina” category can have hundreds of pixels per inch. If you’re curious, you can easily find out the PPI of your screen at DPI Love.

dpi-love

Checking an Image’s DPI

To find out an image’s DPI, right-click on the file name > Properties > Details. You’ll see the DPI in the Image section, labelled Horizontal Resolution and Vertical Resolution.

check-dpi

How to Change an Image’s DPI

You can change an image’s DPI with most image-editing programs, but the feature doesn’t come in-the-box with Microsoft Paint. If you have Adobe Photoshop or GIMP (one of our favorite open-source cross-platform image editors GIMP: A Quick Walkthrough Of Everyone's Favorite Open Source Image Editor GIMP: A Quick Walkthrough Of Everyone's Favorite Open Source Image Editor Read More you can download for free, even as a portable app), you’re all set.

We’ll show you how to change the DPI in both programs, as well as for free online (which is handy if you’re editing images on a Chromebook Edit Photos Just Like In Photoshop: You CAN Do That On A Chromebook! Edit Photos Just Like In Photoshop: You CAN Do That On A Chromebook! The latest instalment in our mini-series looks at the wide choice of high quality photo editors that are available to all Chrome users. Read More , for example).

Change DPI in Photoshop

To change an image’s DPI in Photoshop, go to Image > Image Size. Now this is very important: Uncheck “Resample Image” at the bottom of the window. If you don’t, Photoshop will simply upsample the image, meaning it’s adding pixels without adding detail.

photoshop-change-dpi

The screencapture above is from Photoshop CS2, but the instructions work exactly the same for higher versions of Photoshop, too. If you’ve done this correctly, you’ll notice the file size of the image doesn’t change. Only the end-printout will – you’ll see the same pixels, packed closer together.

Change DPI in GIMP

If you’re editing your image in GIMP, you can change the DPI by going opening the Image menu > Print Size. Then, enter the resolution you require for the x-axis and y-axis, and click OK. Unlike in Photoshop, you won’t need to worry about upsampling.

You’ll notice the print size will change, because changing how many dots per inch you want printed will mean you’re fitting more pixels into the same amount of space, shrinking the result.

gimp-change-dpi

If you keep the chain symbol linked, it will automatically change the y-axis to scale. Un-link the chain if you want to change the horizontal and vertical DPI independently from each other for some reason.

Change DPI Free Online

If you’re in a pinch and you don’t have your graphics program of choice on hand, you can always change the DPI of an image with Convert Town’s DPI-changing web-app, for free online.

All you have to do is input the DPI you need the image changed to, drag-and-drop the file to upload it, and wait. When it’s done converting, it should automatically download it to your default download folder.

convert-town-test

Learning More

There you have it: three of the best free and easy ways to change a graphic’s DPI. It’s not hard to do but trust me: it will save you headache if you get it right before you start your next print design.

Every graphic designer needs to know this whether you specialize in graphics for print or for digital. If you ever need a printed poster for advertising, you don’t want to be caught out by being the only graphic designer on your team but not knowing this basic concept. If you didn’t know about it before, don’t dismay – many basic principles of graphic design 5 Basic Principles Of Graphic Design You Take For Granted Everyday 5 Basic Principles Of Graphic Design You Take For Granted Everyday In the visual age of the Internet it's relatively easy to create your own graphic designs, but they don't have to look homemade. Read More can be learned.

What Concepts Do You Struggle With?

Are there any other graphics concepts you want explained? We’ve got articles on becoming a graphic designer So, You Want to be a Graphic Designer? So, You Want to be a Graphic Designer? Read More – and we can teach you how to profit at graphic design online, How to Be a Profitable Online Graphic Designer How to Be a Profitable Online Graphic Designer If you're a graphic designer struggling to turn a profit, all is not lost. Here are some tips for getting your freelance career back on track. Read More too. If you don’t find what you’re looking for, comment below to let us know what you want to learn next!

Finally, if you have any horror stories of a graphic design project gone wrong and want to share what you learned, we’d love to hear them so we can all save each other grief down the road.

Image Credits: Kittens! by Nicolas Suzor via Flickr.

  1. Vic
    November 4, 2016 at 8:06 pm

    I don't often comment, but your post on changing the dpi was very helpful to me. I am doing some senior class photos for my daughter and it mentioned needed 300 dpi, but was set for 72. I almost came to the conclusion that photos I had taken were worthless, til I read your post.

  2. Tristan
    September 21, 2016 at 9:35 pm

    Hello,
    I'm having a problem that kinda concerns this and something else simultaneously. I have an image that I may want to make prints of. I have both PNG and PDF copies of it, it's been converted into CMYK, and it's currently at 500 dpi, which if I understand properly is well above the standard dpi of 300 that people tend to use for printing. That's fine, but my real issue is that the image itself is rather small (a little less than 8in x 10in), and I wanted to make it at least a little bit bigger before printing it. Is this doable while still keeping the DPI at or above 300?

  3. max
    September 10, 2016 at 1:48 am

    wow someone who knows the difference between ink drops, LPI, pixels, the one thing that is not mentioned in this article that needs to go in is
    For printing, retain the ORIGINAL pixel dimensions changing the resolution from say 4000 x 2000ppi to 36000 x 18000ppi makes the image softer, reduces the corrections you can make in photoshop or their effectiveness and increases processing time. IT DOES NOT HELP TO INCREASE THE FILE SIZE, IT ACTUALLY DEGRADES THE IMAGE.
    If you work in large format, use a higher quality camera, a canon 5dsr (50megapixel) or phase one medium format

    • Krzysiu
      October 29, 2016 at 10:40 pm

      Changing density doesn't change image itself, but image metadata. So if changing ppi degrades your image, changes anything in image, you should consider using better tools. I think you have mistaken print size with image size. Still, upscaling image doesn't mean it always would degrade image. What degrading could be in x2 method?

      And as for rather powerusers - you can script some command line tool. Like batch file. Let me present example for Windows for JPEG (!). You need exiftool (open source). Rename the original file to exiftool.exe and put it in the Windows directory (or to other directory in your %PATH%). Create new file with extension ".bat". Let me explain how it works. You need to drag file and drop it on the newly crated file. At first it gives you name of the file (I like such feedback to be sure I modify correct file), then it asks you about new dimensions. Warning: this code assumes that units are inches (the are rarely different), that you wrote proper number, not gibberish and that file if JPEG (in last case it will just fail, in second it could fail). Now, if author's willing to add my code, I'll be glad to make it better (including choosing from menu standard values, using last given value and processing many files/directories). So if the author wants it, please write to my mail and I'll send you code. So the simple version of code is:
      @echo off
      setlocal
      echo You are about to process image "%~nx1".
      for /f %%i in ('exiftool -s -s -s -jfif:Xresolution "%~1"') do set currDPI=%%i
      set /p newDPI="Enter new resolution (current: %currDPI% dpi): "
      exiftool -P -overwrite_original -jfif:Xresolution=%newDPI% -jfif:Yresolution=%newDPI% %1
      endlocal
      pause

  4. CharleneMcD
    September 1, 2016 at 10:17 pm

    Thank you for the easy to follow directions! You saved me a lot of time!

  5. Nicolas
    August 29, 2016 at 9:00 am

    Hello,

    I am using Window 10 but i cannot vizualise the number of DPI in the case of the files in BITMAP format. I followed the procedure described on this web page ("Checking an image's DPI") but the number of DPI is not displayed. Please could you help ?

  6. John
    August 23, 2016 at 7:12 am

    Fantastic article and amazingly interactive. You laser-targeted my issue and had a direct solution on the same page. BRAVISSIMO!!!

  7. andrew hamilton
    July 29, 2016 at 2:32 pm

    Is there any difference in the result if you use GIMP over the convert.town web site?

  8. Ed
    July 28, 2016 at 8:04 pm

    Thank you! Exactly what I needed and perfectly presented. Saved me a ton of time!!

  9. Elena Mikhaylova
    July 1, 2016 at 5:09 pm

    Thank you so much! It saved me a ton of time!

  10. Joseph Liu
    June 28, 2016 at 9:29 pm

    Very useful. I used the online app to change my 72 dpi pic to a 200 dpi one.
    thanks!

  11. Pam Terry
    May 9, 2016 at 5:38 am

    Fantastic info!! Thank you.

  12. Brendon (Convert.Town)
    April 20, 2016 at 8:23 am

    Jessica - thank you for mentioning my DPI conversion tool. Much appreciated!

    • Angela Mikronis
      May 11, 2016 at 6:05 am

      is there a size limit for the files i can upload as i have a 43 meg artwork i need to be 180dpi and keeps telling me there is an error

  13. Jill
    March 25, 2016 at 6:34 pm

    awesome article! easy to understand! I am subscribing!

  14. alissa
    March 22, 2016 at 12:12 am

    Thank you! I didn't even know that dpi stood for dots per inch! I wrote down the details on how to convert everything and really appreciate it

  15. Barrett Hurd
    March 15, 2016 at 10:35 pm

    Jessica, are there occurred in which you cannot increase the DPI?

  16. Cat Milton
    October 25, 2015 at 1:21 pm

    Jessica, thank you! I'm an iPhone Photographer but my images (72dpi) are often requested for print publications. I've known the images can be 'inter-something' so they're print ready but never known how! You're article has nailed it - and delightfully, easy to follow. Thank you again! xxXxx

  17. Mary Estevez Tunstall
    October 23, 2015 at 6:12 pm

    Awesome informative well written article! Thank you so much for sharing this information! I play around with graphics and saw problems due to DPI even on personal photos Example you have an old Polaroid photo you want to copy and print because they have a tendency to deteriorate Problem go to try to print and it looks horrible due to the DPI being too low So to whoever wrote this thanks "You Rock"

    • Jessica Coccimiglio
      October 23, 2015 at 6:29 pm

      Hello Mary,
      So glad you found the article useful!
      Happy photo printing.
      - Jessica Coccimiglio

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