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I have a photo that I took which is natively 1728px x 2596px. When I open it in Photoshop it shows the picture as those dimensions with Document Size of 24in x 36in at 72ppi.

I want to crop the picture and print it at 2.5in x 3.5in for use in a wallet-sized picture book. Here's what I've done so far, please let me know if this is the right way to go about it or if I'm completely off.

I open the file in Photoshop and crop it to my taste. The new dimensions are 1350px x 1850px. I know 3.5/2.5 = 1.4, so I re-adjust the height to be 1890px so that I maintain the aspect ratio of my desired print size as 1890/1350 = 1.4.

Now I go to Print from the File menu and in the Print dialog under Scaled Print Size I enter my custom values of 2.5in x 3.5in. The dialog states that the image is scaled by 13.33% and has a print resolution of 540ppi. See image below.

enter image description here

Is this the best way to get the highest quality print? I don't know much at all when it comes to resolution or DPI and PPI and what effect those have on the print quality. I tried this method after first cropping and then adjusting the Image Size to be 2.5in x 3.5in under the Image... menu, but that made the print quite blurry.

Thanks for any help.

  • Just to clear up possible confusion — in your sample image here, you've added blur to obscure the subjects, right? Or is it that blurry in the dialog? – mattdm Dec 17 '15 at 3:30
  • Yes, that's right. Should have stated that. – skyline3000 Dec 17 '15 at 14:08
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What you're doing, as shown in the dialog above, should be just fine. You can see What does DPI mean? and What does pixels per inch mean, exactly? for some of the background, and for the ultimate tutorial, How do I generate high quality prints with an ink jet printer?.

But in short, what you're doing seems just right. I think that all you're asking for is confirmation of this, right? If so, yes. Carry on.

  • Okay so, please bear with me for this, if I double the DPI in the image to be 144, the image's width and height doubles in pixels. Then when I go to print at the same size, 2.5in x 3.5in, the PPI also doubles to 1080. Does this imply I will have a better quality image? Or at this size is it basically irrelevant to the human eye? Also noted in one of those articles, do I need to match the PPI to the printer's native PPI? Thanks. – skyline3000 Dec 16 '15 at 22:24
  • It sounds likely that you're using a rescale feature to do that (I don't have Photoshop so I don't know what it looks like in current versions), and it is doubling the height and width in pixels, but just by extrapolating, not because it's creating more information. So, that won't actually cause any improvement. (On the other hand, if you shrink the image in that way, you are throwing away information, making things worse.) – mattdm Dec 16 '15 at 22:31
  • With modern printers, you don't really need to worry about matching the PPI, particularly if you exceed it. For some particular models you may be able to eke out marginally more resolution in this way, but I wouldn't worry about it, particularly because at 540 PPI you have plenty to spare. – mattdm Dec 16 '15 at 22:32
  • I see, I believe my initial resize must have done that, shrinking the image and losing information. Thanks. – skyline3000 Dec 17 '15 at 3:33
  • Yeah, once you have done that, you need to undo or revert the file. Resizing back up won't reverse the operation. – mattdm Dec 17 '15 at 3:36
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There are some things not quite right, but I don't know why it is blurry.

You surely are not printing wallet size on letter size paper like it says? If not (if photo paper), you should click the printer settings and declare the real paper size, specifically so the small image will be positioned on the smaller real paper. That's not making it blurry though.

Your image says sRGB, reasonable and correct. But if like is shown, you specify to use the printers profile (instead of letting Photoshop manage it), but it says the printer settings are using an Adobe RGB profile. That is a mismatch, and the printer profile should be selected to match your sRGB image, or probably better, just let Photoshop manage it. These are details to watch out for.

The image said 24x36 inches at 72 dpi because you saved the image as Save For Web. This strips the Exif which contains the dpi (the web has no use for it, so it saves a few bytes). But then later, if no dpi, then Photoshop assumes 72 dpi. Again, no reason to be blurry, yet. You could save the ppi value by selecting Save - As JPG, instead of Save for Web. But, regardless, you will still have to scale it for printing specific sizes.

You cropped it to 1350px x 1850px, no problem.

Then you adjusted size to 1350px x 1890px for 1.4. "Adjust" is not specific, larger can only mean resample, to be a little larger, creating new pixels not originally in the image (normally not a good thing). And in this case, the image was way larger than needed for wallet size, so it really would have been better instead as just another crop to 1321x1850 (still 1.4). So as to not make it larger.

My guess though, but I cannot place why, the blurry might be caused if you left the dpi at 72 dpi when you did this resample, and that could be bad (depending on what actually happened). I am mystified. I can see it is very blurry.

Wallet size 2.5x3.5 inches printed at 300 dpi (or ppi if you prefer) only needs 750 x 1050 pixels. Often these are printed four on a 5x7 paper.

If you can start over ...

Crop it like you want it... but in this way:

The Photoshop marquee selection box (for cropping, etc) has a top menu bar where you can specify Fixed Ratio, to be say ratio 2.5 x 3.5, or 1 x 1.4, etc, and then any crop box you draw will be 1.4. It's automatic, cannot be otherwise, so your crop will be the specified 1.4. This is the easy way. When drawing that crop box, and BEFORE you let up on the mouse button, you can hold the space bar, and the mouse will move that crop box around, instead of changing its size.

Assuming it comes out about the same 1321x1850 pixels, it will print 2.5x3.5 at about 1850/3.5 = 528 dpi (or ppi, your choice). That is excessively high resolution, more than the printer can possibly use. Won't really hurt anything, but not a precise way. But if that previous Resample Image check box said Resample Image and the ppi said 72 dpi at 2.5x3.5, it will be a much smaller image, only 72 dpi. I don't know what actually happened.

So then reample it (resample check box checked) to be 300 ppi, at 2.5x3.5 inches. The pixel dimensions will be 750x1050 pixels, just perfect for wallet size. 1050 pixels / 300 ppi = 3.5 inches of paper.

The printer can have a much higher dpi number, but it has a different meaning, NOT about pixels. 300 ppi is a perfect printing resolution (for color images).

The Photoshop Resize image tool has a checkbox for Resample Image. Unchecked, this grays out the resample choice, so that the image size in pixels cannot be changed, but the printed size can change (called scaling, specifically, NOT resampling). So if the image size is say 1321x1850 pixels, then scaled to size 2.5x3.5 inches will show 528 dpi (or ppi if preferred). This is what your Print menu box is showing (scaling). Your printer cannot make use of 528 pixels, it does good to manage 300 dpi. It won't hurt, and it won't make it blurry, the printer will just do what it can.

Which is OK, but some think Photoshop can resample better (Bicubic Sharper) than the printer driver can, so another way is to check the Resample Image check box. Then specify 300 dpi (always a fine printing choice) and 2.5x3.5 inches, and it will come out resampled to the desired 750x1050 pixels at 300 dpi.

Why it is blurry is a mystery to me. You say if you double ppi to 144, it doubles pixel size. Right, and what I am suggesting is that you instead say the desired printing 300 ppi there, and also say there the desired size 2.5x3.5 inches, and then the resampled pixel dimensions will be 750x1050 pixels at 300 ppi, the perfect goal for printing wallet size.

I hope that makes sense.

  • I appreciate the effort you put into this answer. The blurriness you see in the photo is artificial, I just didn't want people the details of the photo (notice the printer name is blurred out also). When I said resizing all I was doing was re-adjusting the canvas size, so I didn't actually create new pixels, I just showed more of the picture that was there before. I didn't know about the crop tool being used that way - that will make it much easier rather than trying to eyeball it and then adjust the canvas manually like I was doing. Thanks for that. – skyline3000 Dec 17 '15 at 3:35

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