Photoshop vs Indesign Resolution differences

[Oriana808]

Hi all, have been reading up on this issue and I need someone to explain it to me like I'm 12 :).

I use InDesign to export two different sized billboards, png/jpgs supplied by clients. InDesign is far more efficient for work flow than creating the final billboards in Photoshop.

I understand that importing a 300 dpi png into InDesign automatically creates an effective resolution of 72dpi. So basically I have to ignore the InDesign effective resolution altogether and spend extra time checking the Photoshop resolution of each png? Not very efficient...

Thanks

[Derek Cross]

You're mistaken when you state that importing a 300PPI image into InDesign creates an Effective PPI of 72PPI – PPI, Pixels Per Inch is the correct measurement to use, not DPI – Dots Per Inch is the measurement used for printers, such as laser printers).

When you Place an image in InDesign the Effective PPI (resolution) will depend on the size (dimensions) it's placed in InDesign. Check the Links panel to see the Effective PPI.

For printing images in magazines, books and similar should have an Effective PPI of around 300PPI. Items like posters, which are read from distance, the resolution can be much lower, such as 50PPI.

[Barb Binder]

Hi @Oriana808:

I'm not sure what you were reading, but it's not correct. Here is a visual representation of Derek's answer.

Keep an eye on my Links Panel. The image was placed at the original size so both the Actual PPI (pixels per inch) and the Effective PPI start at 300 pixels per inch.

When I increase the size of the image, the effective of PPI drops down to 173 ppi (few pixels per inch because the image dimensions are now larger). When I decrease the size of the image the effect of PPI increases to 600 ppi (more pixels per inch because the dimensions are now smaller.)

[Oriana808]

Oh ok thank you. In the wrong thread then. My issue is that I build an InDesign (for the web) document to, for example, 900 x 200 pixels. I have a Photoshop file that is 900 x 200 pixels @300 dpi. The InDesign file size should technically match the Photoshop image dimensions. However, the Photoshop image imports into InDesign at effective 72 dpi instead of 300 dpi. No resizing at all.

[rob day]

I understand that importing a 300 dpi png into InDesign automatically creates an effective resolution of 72dpi.

Hi @Oriana808, I think you are getting confused by Photoshop’s Export feature, which is intended for exporting to Web formats (PNG, JPG, GIF, SVG), with no resolution. If you Export a 300ppi image, reopen the exported web file in Photoshop, and check its Image Size, the exported version will reopen at 72ppi with the output dimensions  4x larger.

Note that the Export dialog has no image resolution—the Export is to a pixel dimension, and you can’t specify an image resolution. HTML only handles pixel dimensions and doesn’t consider PPI resolution:

The exported PNG reopened into Photoshop

InDesign takes whatever Actual Resolution the file is saved with, and the Effective Resolution (output resolution) takes into account the image scaling applied in InDesign. If I place the Exported PNG directly on an ID page, it will place at 20.833" x 29.167" with an Actual and Effective Res of 72ppi.

If you want InDesign to place the file at its Actual Resolution of 300ppi, use the Save or Save as dialog out of Photoshop—don’t Export.

[Oriana808]

Hi, thank you :).

Just put in a 12 hr day so will come back to this tomorrow. I've been working in design for 20 yrs and am well-versed in InDesign. Typically I have no issues with image resolution. I'm not sure about exporting from Photoshop as I typically just save the file.

Also as mentioned I get the majority of the artwork for billboards from outside clients, supplied as png or jpg. The image dimensions in Photoshop don't match InDesign.

E.g.:

Client provides a png that is 900x200 pixels @300 dpi. Files size in inches is 3"w.

InDesign file is built (Intent: web) to 900x200 pixels. Files size in inches is 12.5"w.

[rob day]

Client provides a png that is 900x200 pixels @300 dpi

Could you share one of the client PNGs?

[rob day]

Here I’ve Exported a 300ppi PNG, and saved the same file via Save As. Both are placed at 100% directly on the page:

The Exported version Scaled to 24%—the 24% scale increases the Effective Resolution to 300PPI

Have you opened your client’s PNG in Photoshop and checked its Image Size?