Skip to main content
M
mrsammy
Participating Frequently
October 23, 2024
Answered

DPI

  • October 23, 2024
  • 4 replies
  • 444 views

I want to adjust DPI using Photoshop. How do I do this?

This topic has been closed for replies.
Correct answer D Fosse

You're going about this the wrong way. An image is just a certain number of pixels, that's all it is. It doesn't "have" a ppi (not dpi!) and it doesn't have a size.

 

Pixels per inch, ppi, is a simple formula that defines a pixel density on paper, and thus a print size. Pixels per inch.

 

Read the next paragraph carefully:

 

For a given image, a low ppi number gives a big print, but low pixel density (big pixels). A high ppi number gives a small print, but high pixel density (small pixels).

 

Now, you can use the ppi number as a parameter to recalculate the pixel size of the image by resampling the pixel data. But you shouldn't do this unless you have a clear purpose for doing so and know what you're doing.

4 replies

Stephen Marsh
Community Expert
Stephen MarshCommunity Expert
Community Expert
October 23, 2024
quote

I want to adjust DPI using Photoshop. How do I do this?


By @mrsammy


Short answer:


Image > Image Size

 

Longer Answer:

 

Best practice is to adjust the PPI without interpolation/resampling. This adjusts the physical print size without affecting the original pixel dimensions.

 

Once the image is at the target resolution PPI value, you can then evaluate the physical print size and then make an informed decision on whether to interpolate/resample to a different print size.

 

This also works in "reverse", you can resize with interpolation/resampling off to a target print size and the PPI will adjust accordingly.

 

The actual target PPI value depends on image content, viewing distance/conditions and print method.

 

The often misquoted value of 300 PPI (which is from a specific scenario) is often incorrect for other use cases.

 

P.S. The more details and background info that you can provide, the better.

Conrad_C
Community Expert
Conrad_CCommunity Expert
Community Expert
October 23, 2024

You can adjust PPI by choosing the command Image > Image Size, and changing the Resolution value. (It’s PPI because technically, DPI applies only to hardware, not files.)

 

However, before doing so, you must check three things:

  • Is this for print media? Because if it is for any non-print media, the ppi Resolution value doesn’t matter at all, only the image dimensions in pixels matters. 
  • Make sure the image dimensions match the final print dimensions, such as 5 x 7 inches. If you change the Resolution ppi value when the image dimensions do not match its final print dimensions, you might get the wrong resolution when printed.  
  • Decide whether you need to resample, because the controls produce different results depending on whether the Resample option is enabled or disabled when you change the Resolution value. 
    D Fosse
    Community Expert
    D FosseCommunity ExpertCorrect answer
    Community Expert
    October 23, 2024

    You're going about this the wrong way. An image is just a certain number of pixels, that's all it is. It doesn't "have" a ppi (not dpi!) and it doesn't have a size.

     

    Pixels per inch, ppi, is a simple formula that defines a pixel density on paper, and thus a print size. Pixels per inch.

     

    Read the next paragraph carefully:

     

    For a given image, a low ppi number gives a big print, but low pixel density (big pixels). A high ppi number gives a small print, but high pixel density (small pixels).

     

    Now, you can use the ppi number as a parameter to recalculate the pixel size of the image by resampling the pixel data. But you shouldn't do this unless you have a clear purpose for doing so and know what you're doing.

      kglad
      Community Expert
      kgladCommunity Expert
      Community Expert
      October 23, 2024

      in the future, to find the best place to post your message, use the list here, https://community.adobe.com/

      p.s. i don't think the adobe website, and forums in particular, are easy to navigate, so don't spend a lot of time searching that forum list. do your best and we'll move the post (like this one has already been moved) if it helps you get responses.



      <"moved from cc desktop">
      Terms & ConditionsAccessibility statement
      Using the community Terms of use Privacy Cookie preferences Do not sell or share my personal information ad choicesAdChoices