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How to check dpi on each layer or object?

Forum|Forum|8 years ago
August 5, 2017
4 replies
9957 views

Hello.

my question is silly but... I am creating kind of colliage for the print, so I'll use several layers in Photoshop CC... I just want to know what's the dpi of the each element in the art board.

Thank you in advance.

This topic has been closed for replies.

Bojan Živković11378569

Community Expert

@lubalbs

You are right for pixel based layer, every transformation is change to actual pixels which means you are losing quality with each scaling in cumulative way.

When using Smart Object layer things are different. Original image is preserved in background and additional one is created for layer which you see in Photoshop. Every time you make scaling and filter, for example, changes Photoshop will go for original image and recreate new one which will be placed on layer. Effectively you are always scaling your image only once when using Smart Object layer what will result in minimum loss in quality. If you keep image in 100% there is no loss, it is as it is. The only lost is compression when savin in lossy file formats.

lubalbs

Known Participant

Thanks again for your reply.

Do you know if there's a way to place it as a Smart Object from the library then? Or a method other than placing from the library to see it's actual dimensions?
The placement from the library of yours has been the workaround I've used to see when I'm going to exceed actual dimensions, but it would be good for it not to lose pixels when resizing, as you say.

Bojan Živković11378569

Community Expert

Not sure what exactly you want to ask. Right click on image in Libraries panel and choose Place Linked for example. Another way is to drag image from Libraries and it should be placed as smart object.

To place at actual dimensions using File > Place Embedded/Linked you must set resolution in advance or to change it afterwards plus to turn of Resize Image During Place or to ensure that image is at 100% placed.

Use link to my blog post where you can find explanation how to automate task of changing resolution of placed image. You will find ready made actions to change resolution of placed image under

Download Photoshop action to change the resolution of the placed image to 300ppi

Download actions to pace image and match different document resolutions (300ppi, 150ppi, and 72ppi)

If you need to change resolution to some other nember let me know.

In essence you must know resolution of your document. Place image, select smart object layer with placed image then run action like one to change resolution to 300ppi. There are and actions which will guide you through entire process to place image and to change resolution automatically (that is second set - Download actions to pace image and match different document resolutions (300ppi, 150ppi, and 72ppi). You can also assign keyboard shortcut to run action.

Conrad_C

Community Expert

You can check the ppi of images in Illustrator, InDesign, and PDF in Acrobat because their document formats don’t have a specific resolution, and each image is a separate object in the document. The document resolution is limited only by the resolution of the printer or display used for final output.

But the Photoshop document format is pixel-based, so everything in the document is limited by the pixel dimensions you entered for an artboard and the PPI entered in Image > Image Size. If you have a 1000px x 1000px artboard, and you place a 10000 x 10000 pixel image into it and fit it exactly to the artboard, then the pixel dimensions of that image are now 1000px x 1000px because those are the pixel dimensions of the artboard. If the document unit of measure is inches, then the ppi of the document is set in Image > Image Size and all imported images are limited to that.

All of the above assumes you haven’t resized the image after placing it in Photoshop. If placed as a Smart Object, resizing changes the effective ppi of the image. The PPI value you see in Illustrator (and InDesign) is actually Effective PPI, meaning the PPI takes into account how much the image is scaled on the layout. The effective PPI of an image (in Photoshop, a placed Smart Object image) goes up as you scale it down, and goes down as you scale it up, but unlike Illustrator or InDesign the maximum Effective PPI is the ppi in Image Size.

I agree with you that it would be very helpful for the Photoshop Properties panel to report the Effective PPI (not native file PPI) of any image placed in Photoshop as a Smart Object. But currently, Photoshop doesn’t do that. You have to know the native ppi of the image and manually correct that number for any scaling in Photoshop yourself, and then if that value results in a higher PPI than the Photoshop document, then the effective PPI is the PPI of the Photoshop document.

Bojan Živković11378569

Community Expert

@lubalbs When placing images as Smart Object layers Photoshop may downscale image to fit document bounds depending on preferences you set. I will assume that you have checked to convert images to smart object layers. Now you want to keep image to at most, its 100% original dimensions without upscaling it?

Your original image with original resolution will be preserved into Smart Object layer. There are two options to match document resolution so you can be sure that image is not upscaled:

Check resolution of images before placing them and change it to match resolution of document in which you are placing images.
Double click smart object thumbnail to enter editing mode then change resolution from Image > Image Size, uncheck Resample > change resolution then click OK and save changes.

Here is my tutorial on topic how to place actual dimensions when using Place commands which may help https://www.designeasy.co/2017/12/how-to-get-actual-pixel-dimensions-on.html

lubalbs

Known Participant

Thank you so much, the instructions you linked to at the bottom were incredibly helpful and exactly what I was looking for. I am now able to place it at full size at 300ppi, make a note of what the dimensions are and then make sure I don't exceed those dimensions when resizing the layer.

If it's a smart object, it shouldn't be losing resolution when I scale it down, only to scale it back up, should it (for example if I try scaling it down to fit an area but realise it doens't work, so enlarge it slightly again? (With the proviso that I don't exceed the image's original size?)

lubalbs

Known Participant

It won't let me edit my comment. So helpful, Adobe.
So I've just realised that with this method it isn't placed as a smart object, it's placed as a layer.

Which means I assume if I downsize a layer, it will discard pixels, right? I can only size the layer down, not up again (unlike a smart object, correct me if I'm wrong)?

Thank you again.

Chuck Uebele

Community Expert

The dpi will be whatever the entire document is. Files brought in, unless their smart object, will be converted to the master document.

morinaga775Author

Participating Frequently

Hello,

Really? I know that you are able to check dpi of the each element in Illustrator software, but didn't know it will convert all elements to the master document. So. I have to check the dpi of the each element in their own files before bringing them into the master document I guess.

Thank you for your answer!

D Fosse

Community Expert

morinaga775 wrote
I know that you are able to check dpi of the each element in Illustrator

Not really. Ai is a vector application and Ai objects don't have any resolution. Photoshop is a pixel editor, a whole other kind of animal.

On the whole I suspect you misunderstand what pixels per inch (that's ppi, not dpi) really means. It's not a native property, it's just a print instruction. You can assign any ppi you want and the file isn't changed - only the printout size is. Ppi determines how big each pixel will print, but there is still the same number of those pixels in the file.

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