Anzeige von PPI zu DPI ändern

[Alex-Mediengestalter]

Hallo liebe Community,

ich habe eine schnelle Frage. Mir wird in Photoshop die Auflösung die ganze Zeit in PPI angezeigt. Wie kann ich die Anzeige zu DPI ändern? 

Über eine schnelle Antwort würde ich mich sehr freuen!

Liebe Grüße

Alex

[Per Berntsen · Accepted solution]

Hello dear community,

I have a quick question. I see the resolution in PPI all the time in Photoshop. How can I change the display to DPI? 

By @Alex-Mediengestalter

PPI is the correct term (Pixels Per Inch), and cannot be changed.

PPI is optional metadata used by printer drivers to calculate physical dimensions of an image.

Pixel dimensions divided by PPI value = Printed dimensions in inches.

DPI stands for Dots Per Inch, and is the number of ink dots a printer uses to print one inch of paper.

Lots of people (even those who create software) use DPI when they should be using PPI.

[Alex-Mediengestalter]

Wieso exportiert mir Photoshop das Bild ständig in einer Auflösung von 96 dpi? Egal ob ich auf 300 oder auf 72 ppi stelle, nach dem Export hat das Bild konsequent 96dpi. Wenn Photoshop dpi nicht anzeigt, wie soll man dann richtig das Bild aufbereiten dass es die gewünschte dpi für den Druck hat? 

[Per Berntsen · Accepted solution]

Why does Photoshop keep exporting the image to me in a resolution of 96 dpi? It doesn't matter if I set it to 300 or 72 ppi, after export the image has consistently 96dpi. If Photoshop doesn't display dpi, how can you properly prepare the image so that it has the desired dpi for printing?

By @Alex-Mediengestalter

Exporting will strip out the PPI value, because it is irrelevant and unnecessary for screen viewing.

If you open an exported image in Photoshop, it will be assigned a PPI value of 72. It has assign some value, to be able to display rulers (with physical dimensions) and type correctly.

Windows will assign (or at least report) a PPI value of 96.

Use Save As or Save a copy for images intended for printing. Both will retain the PPI value.

[Alex-Mediengestalter]

Herzlichen Dank, es hat funktioniert.

[Conrad_C · Accepted solution]

It cannot be changed to DPI, because Photoshop uses a strict technical definition of image resolution which is PPI (pixels per inch).

Under that definition, there is a difference between PPI and DPI:

Pixels per inch can be saved with image files, and indicates the intended pixel density of the image.

Dots per inch is not associated with image files because it is a hardware specification, the pixel density that can be reproduced by a device such as a printer or scanner. Because DPI is not associated with image files, it is not available in Photoshop.

For example, it is common to send a 300 ppi color image to a 2400 dpi platesetter or printer.

In casual use, it’s common to use PPI and DPI interchangeably. But because they are technically different, Photoshop respects that difference.

[Alex-Mediengestalter]

Wieso exportiert mir Photoshop das Bild ständig in einer Auflösung von 96 dpi? Egal ob ich auf 300 oder auf 72 ppi stelle, nach dem Export hat das Bild konsequent 96dpi. Wenn Photoshop dpi nicht anzeigt, wie soll man dann richtig das Bild aufbereiten dass es die gewünschte dpi für den Druck hat? 

[Conrad_C]

Per Bentsen answered correctly above, but if you want more details: It depends on the format and method you are using to save the file for printing, because some Photoshop commands save ppi resolution, but some commands do not. You may have used one that does not.

If an application tells you the image is 96 ppi when in Photoshop it was 300 ppi, this is what is probably happening: You used an export command that does not embed ppi metadata, so the receiving application assumed its default value. It sounds like the application you used defaults to 96 ppi when ppi metadata is missing. Other applications default to assume 72 ppi. But it is important to understand that this is not reporting the actual image ppi, because there is none in the file. 96 ppi is an assumption made in the absence of an actual ppi value.

Note that ppi metadata is not always required to print an image at the correct size. If it will be printed by software that sets the image size on the page, there is no need for ppi metadata because the print dimensions in inches/cm will determine that.

For example, if you have a 3000 x 2000 px image at 96 ppi, that means if printed at 96 ppi, it would be 31.25 inches long, not a typical print size. But, without changing anything in the image itself, if the print software sets a print length of 10 inches, the effective (after scaling) ppi will now be 300 ppi. Because the 3000 px length will now be divided by 10 inches, and 3000/10 = 300 ppi effectively.

Now, there are some workflows where it is useful to embed a specific ppi metadata in the image. This is usually done to communicate the intended print dimensions to the receiving software that will print it. If this is what you want, always use the File > Save As or File > Save a Copy commands to create the version for print. Those commands always embed the ppi value into a JPEG, TIFF, or PSD format file.

If you instead use a command on the File > Export submenu to create a file for print, the ppi metadata will be missing. This is because commands on the File > Export submenu are not intended for print. They are intended for screen delivery (web graphics, stills for video, mobile app design). For screen delivery, ppi is not needed, so it is not included. Excluding metadata makes the file size smaller, which is important for web/mobile graphics.