Changing Resolution Without Changing Quality


Adobe® Photoshop® Intensive


Lesson Info

Changing Resolution Without Changing Quality

We've been talking a lot about image resolution there's a couple of ways you can figure out what your image resolution currently is okay should you need to change it as well as see the pixel dimensions that make up your image? Because that's important stuff to have okay, so much a couple of different ways to access that information the first way is down at the bottom of an open image window okay, it's a little bit hard to see, so I'm gonna cruise on down to the bottom and then zoom in so right down here, the bottom left of your document you're going to see a zoom percentage that's the level of zoom that we currently have going on in our image and then you're going to see some words down here now the words that show up or the information that show up is dependent upon which option you've picked in this little rightward pointing triangle ok, some al amusing back out now that you can see where to click I'll soon back as he can actually see them. Indeed, you can set that little piece of in...

formation to say most anything you want the one that I find very useful is document dimensions ok, so if you change that to document dimensions, watch how that information down there changes so now is going back in so now we're saying, oh, we're seeing the physical dimensions of our image at the current resolution so if I were to print this thing right now, it would be five point, six inches wide by three point seven, seven inches tall and a resolution of three hundred pixels. Prince pp I so you already know that three hundred is high resolution, so the pixels air really, really timing, so that print will look very good. It won't look like it's made from legos. Ok, so that's one way you can see that now seem back out another way you can find out that information and experiment with different resolutions, settings he's in the image size of dialog box, so we're going to cruise up to the image menu the very top of your screen, and they were going to cruise down to image size, and if you're a fan of keyboard shortcuts again, these were the keyboard shortcuts over here for that dialogue box, and when it opens, we can see all kinds of wonderful information about this here image, and I'll move this up a little bit so everybody can see it let's just start to talk and work our way down in the style lock box so you can see how it's got sections and there's a little line around each section that lets you know those settings go together. So the first thing that we're looking at is purely pixel dimensions and I can see that this image is made from six hundred ninety eight pixels wide by eleven hundred thirty one pixels tall ok that's how many pixels make up my image? And as you can see, these boxes are editable. So if I needed to save this image for the web and I knew that I needed an eight hundred, you know, pixel wide image I could simply type eight hundred here, but as I do that you'll see how the pixel the file size of my image I wish this said file size right there, but it doesn't right now my document takes up five and a half megabytes of space on my hard drive. Okay, because it's got so many pixels in it, that is what determines the hard drive space resolution does not determine hard drive space at all chaos the pixel dimensions that determined hard drive space so I can see here how much hard drive space I have. Well, if I reduce the number of pixels by with and was gonna type eight hundred the high changes automatically because photo shop assumes that I wantto keep the same aspect ratio. Ok, so now you can see that this new image should I accept this smaller size is now greatly reduced in file size, so it was five point nearly five and a half megabytes now it's going to be just a hair over one mega by okay, so you can see how reducing pixels reduce his file size and as a result, a little quality. Ok, so now I'm going to go back to my original settings. This is a fun keyboard shortcut for you. I want to revert to my original with without closing this dialogue and opening and back up, I can trigger a recent button by holding down option on a mat or ault on a pc and watch how the cancel button changes to reset, okay, so that will zero out the settings, the changes that I've made back to the default settings when I first opened that dialog box. So while holding down option on a mac are all on the pc, you can click the reset button and then let go of that modifier ok, so now we're back to square one so that's what this area is about this next section is cryptically called document size. I wish it said print size because that's all it's referring tio, this information on lee comes into play when you're going to print the image if you were to print it photo shop is dutifully telling you how big the sucker would be, okay, I can change information in here too, ok, so if I highlight the resolution measurement we know three hundred to be high resolution if I change it to something really low all this type in seventy two okay, watch how this information changes as I do that okay, so what I've done is I've taken really small pixels three hundred pixels per inch resolution measurement and I've may the resolution number smaller, thereby making the pixels bigger and it suggested the number of pixels that will now be in my image should I accept this change? Okay, now look at the file size different difference now we're at, you know, three hundred twenty three ok? We're not even at a mega by okay, so my point of all this to show you how these these boxes change, they trigger other changes according to which box you you edit okay, everything that we've done so far in the style of box would be reducing image quality with we'd end up with a smaller file size image, less detail and so on and so forth okay, so I'm gonna do my reset trick again so press and hold down option on a mac or halt on the pc so that my cancel button changes to reset, so we'll go back to square one again so unless you really want to change the physical size of your image, you need to make this dialog box that the field stop changing each other okay, so what we want to do is we want to figure out a way to lock this information we want to lock file size and pixel dimensions thereby locking quality of the image and then we can play around with resolution all day long if we need to if we're going to print this image let's say we we do want to print this image but maybe you don't really know what size you can print it you know how many pixels do I have? How big can I can I print eleven by seventeen or can I print a you know, a five by seven or none of those what can you do? So this is a great way to experiment with resolution and figure out how big can you go at the quality that you need? Ok? So the trick to this is to turn off an option at the very bottom down here this guy right here and I'll zoom in so you can see it re sample image while that has turned on the changes you make him one of those fields effects image quality because it will change your images dimensions but if you can lock those dimensions your quality is locked into, so I'm going to zoom back out because I want you to see what happens when I toggle this check box off watch this area right here when I turned that check box off I can click all day long and I cannot edit those fields anymore. Okay, now we can experiment with resolution and you're going to see these fields change, but just these two and it's going to show you what your maximum print size will be at a given resolution. Ok, it's really slick thing and how do you know what never to type into? This resolution failed? And again, we're playing like we're going to print this image otherwise resolution doesn't make a hill of beans difference on anything this number you can memorize three hundred pixels per inch and just roll that for the rest of your life and you will probably be fine. Ok, three hundred pixels prince makes really small pixels that are gonna look great when you print. Some printers can take advantage of smaller pixels than that. Not all of them. Ok, so if you're printing on your own printer at home, then do a few tests. Ok, start out with an image that I would say anything over two hundred forty pixels print is gonna look great if you drop the pixel sizemore with some printers it's overkill it's going to take the printer longer to print the image and the ink can build up on the page a little too much because it's working harder to try to spray those dots smaller and smaller and smaller okay so in some instances with some printers you don't gain anything by you know creating an image that six hundred p p I you you know you'd be hard pressed to print the two out until the difference between the two so you can do some tests start with two hundred forty pixels cringe or if you just want to memorize three hundred because that's been the golden standard high resolution rule for eons you can stick with that okay so now it's lists hit was hit home the concept of how squishing those pixels just like pressing brown sugar into measuring cup reduces surface space so right now if we were to print this image it would be nearly six inches why by nearly four inches tall okay so watch those numbers as I increase my resolution so I'm going to go up to four hundred it's now I've got an image that would print at about a three by four ok so I'm going to raise it even more will go to six hundred now I'm gonna end up with a postage stamp you know an image that's under three inches wide by just under two inches high so you see how making the pixel smaller and smaller shrinks the print size ok so that's important to know if you're dealing with an image that doesn't have a whole lot of pixels like this one and you need to print it you're a little bit stuck in that let's say three hundred is what my printer does a good job with it home I really can't get over you know nearly a six by four print out of this if I want eight by ten forget it okay, so you can experiment with either the resolution field or you can experiment with size so let's say that you really want to eight by ten out of this picture you know do I have enough pixels to do that? Well, I don't know let's see so let's type eight into the whitfield and then mihai changes automatically okay, so I can see ok if I do want to eight inch wide print then I can't have my pixels any smaller than they would be at two hundred twelve pp I ok? So I find that doing a little bit of experimentation inside the style log box with the re sample image option turned off this is what really made resolution makes sense to me I mean the cooking analogy the brown sugar analogies is fabulous but you can see it in action here and this is the only place you can actually see the change happening because again your monitors simply cannot display you cannot see a difference between really small pixels and big ones on the screen, so this is the only place you can see that change so great place experiment see what the maximum size print you can get out of an image at a given resolution? Okay, I can experiment with that number all day long and my image quality will never ever, ever, ever change no matter what anybody tells you okay, so I could click ok say this is a photo shop document opening a year from now and I could change the resolution back tio you know three hundred or whatever I want and the image quality is never going to change because this information is locked and that's for your image quality is coming from pixel dimensions which determines the file size of that image ok that's kind of a difficult concept that you may have any questions on that one part? Yes. What if you want a really big format for it? Do you have to shoot it with higher pixel resolution? Yes. Great question. What do you do if you need more pixels that let's say we really want eleven by seventeen out of this great go get the shot again, get the shot again so you would want to be shooting on the highest it's quality setting on your camera so that you're capturing more pixels that's the best way now that said, you know it used to be a huge no no in photo shopped to make images bigger than they really are graphic designers will call that up sampling it's just simply not that big of a problem anymore the program has gotten so much better at faking pixels which is called interpolation that's the adding of pixels that weren't there originally okay so funny shop has gotten really really good at it. Okay, so let me show you how to do that if you need tio I'll go ahead and press option or all and click the reset button so we're back at square one if you want to up sample or make your image bigger than originally was you do want to leave on re sample image because photo shop is gonna have to change this stuff's gonna have to change pixel dimensions okay? And so what you can do is you can go down here in the document size area and you can change these poppet menus two percent hey, and I like to use it this way you could type in the dimensions you need if you want but I'm pretty visual person and while I passed on my math classes I don't really like to use that so I don't do it visually so I might know that okay, well I just need this image to be one hundred fifty percent of what it wass hey so you could type that right man so I can type one hundred fifty into my image now look what happened up here in my pixel dimension area my pixels increased okay and photo shop is going to be faking them so it's not gonna look as good as the original but it looked pretty good okay, now I can see that I now would be dealing with should I choose to accept this information and I'd have to do that by saying ok and then saving the file I'm not really changing anything right now I'm experimenting then my file sizes now twelve megabytes versus the five and a half that originally was so you can see evidence of it getting bigger and you was simply press okay this dialogue or pop up menu rather at the very bottom let she find tune the process in which photo shop is using to fake those additional pixels that weren't there at capture okay, so thankfully adobe has added little parentheses that help us figure out these rather cryptic terms by linear by cubic smoother of course everybody knows what that means so basically what you want to do if you're if you're enlarging an image, then you're going to choose by cubic smoother which in princess says best for enlargement okay, I do have some buddies that swear by using by cubic sharper for up sampling image bigger that it originally was to be honest with you I can't really tell the difference when I use both of them side by side comparison I have no idea so this is a way that you can increase the size of the image beyond what was originally there yes, sir. What do you think of the concept? Some people have that when you're gonna upscale like that there are upsides that you just go up ten percent of the time rather than like fifty percent that you're better quality you agree with that or what do you think that's a great question in previous versions of photo shop before it got really really good at interpolation the adding of pixels that weren't there it capture then it was the only way you could skin by making an image bigger without the whole world being able to tell when she print the darn thing is to increase its size in no more than ten percent increments at a time. So the theory was that you would instead of one hundred fifty you would type one hundred ten and then you would say ok and then you would open the dialogue box again and you would increase it another ten percent and you could do that as many times as you want until you lost enough quality that you know it was obvious in photo shop see it's fine it's just not an issue like it used to be. Now I'm not saying that you could increase this two hundred three hundred percent and not be able to tell the difference of course you will but if you're increasing a little bit then it's ok to to go ahead and do it all at once, but again to your own tests to see there are third party plug ins and the name is escaping me right now. Fractal um, genuine fractal. Thank you. The studio audience genuine fractals is a great plug in that there is some serious black magic going on underneath that hood because you really could take this image and blow it up to billboard size, and it would look fabulous. So that that's another option. If you really get into the problem of needing the image to be larger. Yes, sir. So where would you put this? In the work flow? Where would you put this in the work flow? I would do it first if you possibly can. Yeah, before you, because any kind of manipulation is going to affect the quality of your image. So if we've done a whole lot of color, correction and head swapping and who knows what else? I would want to get my re sizing done up front, so I'm working with the best quality throughout the rest of that process as I could, so I would do it as quickly as you can quick question lisa if, if the photo is not for a magazine or newsprint. But somebody's going to take it to a lab for printing enlargements? What dp I should they save it as or p p I that's a good question if you're going to take it to a lab to have it printed I like making my photos the size and I'm going to print first and that's the rest of what we're going to talk about here in just a moment I don't I would not want to give the lab leeway to do any about those changes, so you're going to ask the lab what resolution they want and you're going to figure out what size you want to make it and you're going to make those changes yourself before you send it on otherwise you risk the image being cropped and unexpected ways you know? So I'm a bit of a control freak a lot, so I like making sure that my image is exactly like I want it okay? Lisa sylvia would like to know how much for re sample can do without any worries for printing. I'd say between twenty and fifty percent in my opinion, you know that depends on the printer and certainly depends on the image, so you might want to do some tests but c s five it's I'm telling it can fake pixels like you've never seen, so yeah, between twenty and fifty percent I would think question from guitar goddess does it matter whether images come off the camera into photo shop at seventy two or one eighty v p I I noticed that my two cameras download the images and they default to different settings does that make any difference with the quality you're starting with before doing any adjusting that is a great question I wish I had thought to plant that question thank you guitar goddess it absolutely makes zero difference at all because what you've just seen when we were I'll go ahead and reset it back when I turned off three simple image you saw me change resolution all day long and none of this information is changing which means quality is locked same thing on your camera it does not matter what resolution it doesn't matter what size pixels your camera is making it because you can make them any size you want in photo shop but the trick is to turn off that re sample image so some cameras capture seventy two pp ice and captures at one fifty some even come off a three hundred it simply does not matter because you can change that measurement here in the image size dialog box as long as you turn off free sample image kathy would like to know when you re sizing is it better to do it with inches or change it two percent oh that's a completely personal preference whether you want to do your resizing with percentages or inches since I spent most a lot of my life in the web world, that's actually what my mind degrees in web development pot. So I'm just have a habit of working with pixels so as totally up to you doesn't matter. I think you may have answered this talking about your work flow, but lennon sharp glass asked to sharpen before or after you resize sharpen is the very last thing you do in my opinion. Yeah, pretty destructive thing. Um, I have a question from vincent lindsay and he said you may have answered this also, but he has, um he prints at a twenty four by thirty six print, and he said it so block yet one fifty p p I and two. Forty p p I would like to know why that isthe not real sure without knowing what printer he's using, but I would keep bumping up the resolution until it it looks good, you know, just be sure and turn every sample image off and keep tweaking that resolution. He'll get smaller, smaller, smaller, smaller prince.

Class Description

In this special photoshop tutorial, you'll dig into Adobe® Photoshop® CS5 with Lesa Snider, author of Photoshop® CS5: The Missing Manual. There is so much to cover in Adobe® Photoshop® CS5 that we need almost a week to cover everything. In this special 4-day workshop you'll dig into Adobe® Photoshop® CS5 with Lesa Snider, internationally acclaimed instructor and author. Lesa is informative yet entertaining with a unique way of explaining difficult concepts so you understand the "why" behind the "how". Get ready to spend a fun, high-energy week digging into the power of Photoshop.

Software Used: Adobe Photoshop CS 5.1


1Introduction: Nitty Gritty Basics + Layers 2Workspace Overview 3Q&A: Workspace 4The Truth About Resolution and File Formats 5Changing Resolution Without Changing Quality 6Q&A: Resolution and File Formats 7Resizing with the Crop Tool 8Cropping with the Ruler Tool 9Resizing with Content-Aware Scale 10Resizing for Print/Web 11Layers and Layer Types 12Duplicating, Moving, and and Aligning Layers 13Q&A: Layers 14Creating Reflections 15Layer Alignment Tools 16Simple Slimming Technique (Resizing Layers) 17Colorizing a Black and White Image 18Creating a Solid Color Fade with Fill Layers 19Layer Masks: Hand Painted Image Collage 20Layer Masks: Gradient Mask Collage 21Layer Blend Mode Collage (Include Load Images as Stack) 1Using Selections Part 1 2Using Selections Part 2 3Q&A: Selection Tools 4Color Selections: Fixing Animal White Eyes 5Tightening Up Layer Masks 6Painting Selections with QuickMasks 7Using Vector Drawing Tools 8Vector Shapes: Creating an Oval Vignette 9Vector Shapes: Rounded Edges to Photo 10Use Channels to Create Selections 11Tough Selections Around Hair & Fur 12Refine Edges Part 1 13Refine Edges Part 2 14Creative Edges on Photos 15Embellishing with Vector Art 16Creative Vector Photo Frames 17Editing Smart Objects 18Smart Objects Template: Creating Dark Edge Vignette 1Smart Objects: Selective Blurring 2Smart Objects: Selective Sharpening 3Sharpening with the High Pass Filter 4Q&A: Sharpening 5Auto Color Adjustments 6Shadows and Highlights 7Using Levels 8When to Use Smart Objects 9Using Curves 10Lightening and Darkening with Blend Modes 11Enhancing Eyes and Teeth 12Changing Colors with Hue/Saturation 13Changing Colors by Hand Painting 14Faux Dodge/Burn: Reduce Wrinkle 15Color to Black and White 1Healing Brush 2Content Aware Fill 3Using Text in Photoshop 4Designing with Baseline Shift 5OpenType Fonts 6Placing Text Behind an Object 7Barely There Text: Faded and Hollow Text 8Pushing Photos Through Text 9Adding Texture to Your Text 10Convert Text to Paths 11Combine Images using Advanced Blending 12Realistic Photo Aging 13Faking HDR 14Wrapping Texture Around an Object