255 Check resolution in a PDF

- [Voiceover] As all designers know, it's critical to be able to tell what an image's resolution is. You need to use enough pixels in an image, like 250 or 300 per inch, in order to avoid pixelization or stair-stepping when you print it out, or sometimes even when seen on screen. Now, it is simple to figure out what an image's resolution is in InDesign. Right now we're looking in Acrobat at a PDF but let's quickly jump over to InDesign and look at the same page.

You simply select an image, and then go to the Links panel, and you can see in this drop-down area what the resolution is. It started out at 300 pixels per inch, and because we've scaled it down, it's now 1452 pixels per inch. And when you export something to PDF from within InDesign, I'll go ahead and do that right here to the Desktop, and we'll call this G B white paper, you have the option here under Compression of what to do with the resolution. In this example it is going to downsample all the way down to 150 pixels per inch any image above that, because these are the last settings that I used.

But I'm gonna cancel out of here, because the idea is that you do not have the original InDesign file. You're given a PDF. Where is there a panel in Acrobat that will tell you what the resolution of an image is? Do we have something like that, and indeed we do. You don't have to purchase a really expensive plugin to be able to get this kind of information from any PDF. So, if your boss gives you a legacy PDF that somebody created 10 years ago, and wants you to do something with it, or the original InDesign file got damaged, or whatever, you can still find out this information in a PDF.

And you do that in any recent version of Acrobat Pro. I'm using Acrobat Pro DC right now, which is somewhat different from Acrobat 10 and 11, but in Acrobat 10 or 11, what you want to find are the tools called Print Production, and they would appear in this list here, and if not, there would be a little tiny triangle where you can click it and choose Print Production. You don't have that in DC, you have something much better. I'm actually getting to like DC a lot. I love this field called Search Tools. And what we're looking for is either Print Production tools, so I start typing Print and you can see it comes up with the category, but actually, in Print Production, which has a lot of tools, we want one specific tool called Output Preview.

So if I start typing Output, it appears there. And within Output Preview we're going to be choosing a view called Object Inspector. So I can even start typing Object Inspector, and I love how Acrobat Pro knows that this command is inside all of these other places. So I can even type Inspector. I'm sort of showing off a little bit that I'm kind of happy with what the Acrobat team did here. Anyway, so we want the Output Preview dialogue box from Print Production. And here, whoa, it's a really crazy, busy dialogue box, but just put your eyeballs right here where it says Preview, and choose Object Inspector.

With the Object Inspector, you can click on anything in the PDF and it will tell you a pile of information. CMYK and so on, but here's where we're looking, it is 300 by 300 pixels. That's fine with me. How about this guy? Oh, this guy is only 103. What about this little guy? Let me zoom in more so you can see him because it's actually kind of funny. The font, oh you meant typeface. (chuckling) That's our hipster designer. I click on it, and hipster designer is 204 pixels, so that's pretty good.

Now you might be thinking, do I actually have to go through every single image here and find the problem children? No, there is a slightly more advanced feature in Acrobat. Close out of Output Preview, and one other tool within the Print Production family is called Preflight. So select Preflight, open it up, give it a second to load the profiles. Now, this also exists in earlier versions of Acrobat Pro.

It's been around for a while. What you want to do is go to PDF Analysis, and right here, list color and grayscale images that aren't within 250 to 450. That's fine with me, you could edit the setting if you wanted to, but I'm just gonna leave it at that and click Analyze. It goes through the document and, bang, it is done. Here are the problem children, all of these images are not within that range. And I could click it to jump right to it so this background texture is weird, it's 614 by 133.

And this image right here is 181, so on. You could make reports, you could have it create comments, I love this, insert Preflight results as comments. And then, let me close this out, and back up, and you can see that it puts this rectangle around everything that doesn't work. And there we go, there's another one up there. So, now that you have the images that are too low in resolution, well, actually, that's the end of the tip. But I have to add a little bonus, which is how to fix those things.

Now, let's come right here to this guy. And I'll zoom in a bit so we can see him better. We want to be able to edit this image, so we're going to look for a different tool. I'm going to press Escape twice to get back to the document and then we get our search field again here, and we want to go to Edit. We want to edit the PDF, so choose Edit, and now, I can select this image, right click and choose Edit Using, and I'll want to use Adobe Photoshop.

And it that it uses transparency, might be different, you always get that, don't worry about it. And here, we would change the image size, we would just ramp it up a bit. Let's make this 300 pixels per inch, and we might want to Bicubic Smoother, that sounds fine. And we'll click OK and then close the document. We're gonna save the changes because we're saving it right to our PDF. Go back to the PDF, and now this is actually a higher resolution.

And if you want to check, we're gonna go back to the document, and we'll get back to the Object Inspector in Output Preview, and click on this guy and look at it in Object Inspector, and there he is, 300 pixels. Isn't that cool? Alright, so now you know how to find the resolution of images with our friend the Object Inspector, how to have Acrobat perform a quick scan throughout the entire document with Preflight, and how to fix the images in Photoshop.

There you go.