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Chris  P.  Bacon
Inspiring
December 8, 2022
질문

How do I check the DPI of an image for specifically A3 landscape print?

  • December 8, 2022
  • 4 답변들
  • 12885 조회

More specifically, I should check the print DPI for an A3 crop of the image.

 

이 주제는 답변이 닫혔습니다.

4 답변

Participant
November 18, 2023

you'll need to know the original image's dimensions and the desired print size. Once you have this information, you can use the following formula to calculate the DPI:
DPI = (Total pixels) / (Print width in inches) / (Print height in inches)

Keep in mind that 300 DPI is generally considered the standard for high-quality prints, so if you want to achieve the best possible results, you'll need to make sure that the original image has a high enough resolution.

D Fosse
Community Expert
Community Expert
November 18, 2023

@mick33700021lnpp 

 

Once again, an ink dot is not the same thing as an image pixel!

 

"Dots per inch" is incorrect and misleading. "Pixels per inch" is the correct term. This is not ink dots,  this is image pixels.

 

That so many use incorrect terms does not help understanding.

Brad @ Roaring Mouse
Community Expert
Community Expert
December 8, 2022

There are a few ways to determine the PPI. One of the simpler ones, since you're in Photoshop already, is to look at Image > Image Size. On your cropped image, type in the dimensions you want and the PPI will reflect it's new essential resolution: e.g. in my example I'm using the width of a vertical A3 (29.7) to see what my original 300ppi image would be at that width = 218-ish.

 In your case, type in 42 cm for width (landscape)

Mylenium
Legend
December 8, 2022

The DPI setting is part of the document properties and can be viewed in the file info or seen in the image resize dialog for instance. If you just cropped it from a larger image that had already correct values, that info doesn't change.

 

Mylenium 

Chris  P.  Bacon
Inspiring
December 8, 2022

I am asking for DPI not for PPI and DPI is calculated for print area.

How do I see in Photoshop what will the DPI be if I crop my image to A3?

The DPI is not visible, not in the Info panel, nor in the file info section or document properties.

There is no "DPI" shown in the screenshots you sent.

TheDigitalDog
Inspiring
December 8, 2022

DPI and PPI are used interchangeably to some degree. In Photoshop, which works only with pixels, it's PPI. A product that makes or uses dots would be DPI. 

300 PPI in Photoshop could be output to 300 DPI. Or not. But in Photoshop, it defines a "Size" using pixels; it is a pixel editor. 

Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"
TheDigitalDog
Inspiring
December 8, 2022

In Photoshop, several ways to check what's currently set. Try Image Size for one, or you can set up this info to show in your Info Palette if you select the option. 

Does it matter; not really, no. This is simply a metadata tag. The number of pixels is key! 1000x1000 pixels at 300 dpi, 1000 dpi or 72 dpi is the same. It's 1000x1000 pixels. 

More here (an old but still valid primer):
http://digitaldog.net/files/Resolution.pdf

Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"