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dermottferris
Participating Frequently
September 24, 2017
Question

Why does Photoshop open image as Pixels Per CM not Pixels Per Inch?

  • September 24, 2017
  • 3 replies
  • 9869 views

I am running Photoshop CC 2017.

Our team shoots images, edits and saves them as 2500x2500px @300ppi. However recently Ive noticed when editing images from a PhaseOne camera using CaptureOne they have been opening as Pixels per CM in photoshop. This could be due to the Capture one software. However, Ive had images form clients that also do this.

The reason why it is important to display as ppi is due to us having 'Actions' that make these dimension and resolution changes. So when I run my action over an image that has opened as ppcm, it will convert it to 2500x2500px @300ppi, BUT because its displaying at ppcm it will make this 181.15ppcm Which is actually 299.99ppi.

Our DAM Software that stores our Images won't accept Images that aren't 300ppi.

I have made more actions that change the image from ppcm to ppi, but It seams to default back when saving. The only way Its worked is if I manually change it. This is not possible as we process a lot of images.

I called Adobe, and they said it was only possible to default ppi for when you create a document.

Q: Is there a way to make photoshop default open an image as ppi?

Q: Is there a action you could suggest that would fix this?

Q: Is there a way Bridge CC could open the file in ppi, much the same as Lightroom in its preferences?

Thanks!

This topic has been closed for replies.

3 replies

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Pixelpaddler
Known Participant
February 19, 2020

After discovering a similar problem with images being opened showing 72 pixels per centimeter, found that the units seemed related to the file downloaded from University of Michigan. When I created a blank doc, 8.5x11 in., 300 ppi and Place>Embedded the download, the resulting file shows pixels per inch.

 

You might also be "inheriting" a unit set by the creator of your files. 

Stephen Marsh
Community Expert
Stephen MarshCommunity Expert
Community Expert
September 25, 2017

Q: Is there a way to make photoshop default open an image as ppi?

Yes, a script or action can be set to change the opened image’s resolution unit value to PPI, this can then be automated to be applied on every image opened into Photoshop using the File menu > Scripts > Scripts Events Manager.

The following image uses a different script and is simply used to illustrate:

Q: Is there a action you could suggest that would fix this?

If other software is marking the images in CM rather than IN, then you will need to fix it at the source, otherwise the Script Events Manager would hopefully fix the issue on open, save, or export.

Q: Is there a way Bridge CC could open the file in ppi, much the same as Lightroom in its preferences?

Bridge is a file browser, it will show the metadata value in the file. It appears that Bridge shows the value as PPI, even if the file is saved as PPCM.

Another option would be to use ExifTool to batch process folders/images, changing the unit value from CM to IN:

Re: Bridge thumbnails not showing correct resolution

JJMack
Community Expert
JJMackCommunity Expert
Community Expert
September 25, 2017

As you note Capture one is not Adobe software.   If it is important that the  images you process are in inches and have a 300 DPI resolution that should easy to accomplish.  Record an action the Step 1 Set Photoshop ruler units to inches and Step 2 record menu Image size make sure resemple is NOT checked set resolution to 300DPI and click OK.  Not a Single image pixel well be changed and no pixels will be added.  Once recorded use the Script Event Manager and set up two events an Open document event and a new document event trigger this Action.  When ever a new document is created or an existing file is open.  Once the document is in Photoshop the fist thing that will happen is Photoshop ruler units will be set to inches and the document resolution will be set to 300DPI.

JJMack
    D
    dermottferrisAuthor
    Participating Frequently
    September 25, 2017

    Thanks for that,

    I have however already tried these.

    The record action doesn't record when you change the ruler from CM to inches or and other format. Unless there is another way to do this? Ive just been right clicking the ruler and choosing from there.

    The Script manager is exactly what I am looking for to automatically apply an action to my files when opening. Unfortunately is still doesn't solve my issue due to the action not working.

    The Actions I create won't record the change from cm to inch under resolution (changing from the dropdown menu in image size). It will change it to 300ppi and then keep it on pixels per CM which makes it 118.15ppcm which is actually 299.99 ppi. And our software needs it to be 300ppi.

    The only way Ive found is to manually opening each image and changing it to ppi then making it 300ppi then saving.

    Any thoughts?

    JJMack
    Community Expert
    JJMackCommunity Expert
    Community Expert
    September 25, 2017

    Yes Photoshop does not seem to change image size resolution correctly.  For some reason it converted 300DPI set in the Image size dialog to 118.11 Pixels/centimeter when ruler units are inches?? Go figure out the on 118.11Pixels/centimeter is 299.999DPI.

    The document I created  in the new document dialog was 30CMcx20CM resolution 100pixel/centimeter

    The event change that document to 10" x 6.667"  so ruler units was changed to

    30cm at100px/cm=3000px and 3000/300dpi = 10"   so CM to Inches seem to go well the action step recorder  was Image size resolution 300 per inch why did Photoshop convert that to 188.11 Pixel/centimeter?

    JJMack
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