So what can you do to make photos you download off the internet appear just as high quality when printed as photos you took yourself with your digital camera? The answer - absolutely nothing. There simply are not enough pixels in most internet images to allow them to print at high quality, at least not without printing them at the size of a postage stamp, that is.
Let's find out why. First of all, let's get off the topic of downloading images from the internet, since we really shouldn't be doing that anyway without permission from the copyright owner, and look at image resolution in general.
I cover it in much more detail in the Image Resolution, Pixel Dimensions and Document Size tutorial, but let's do a short recap.
The term "image resolution" means how many of your image's pixels will fit inside each inch of paper when printed. Obviously, since your photo has a fixed number of pixels, the more of them you squeeze inside each inch of paper, the smaller the image will appear on the paper. Likewise, the fewer pixels you print per inch, the larger the image will appear on paper.
The number of pixels that will be printed per inch is known as the resolution of the image, or "image resolution". Image resolution has everything to do with printing your image. It has nothing to do with how your image appears on your computer screen, which is why images you download off the internet usually appear much larger and higher quality on your screen than they do when you print them.
Download this tutorial as a print-ready PDF! I always laugh every time I see this photo of a horse I took while driving around the countryside one day. Normally this horse stands proud, powerful, full of grace and dignity, yet I seem to have caught him in a rather unflattering moment.
He's standing on a bit of a strange angle, he has a piece of straw dangling from his hair, and he seems to be in the middle of chewing his food. Either that, or he's desperately trying to crack a smile for me. In either case, since this guy is already embarrassed, as am I for having taken this wonderful photo, let's use this image as an example. First, let's look at what Photoshop can tell us about the current size of this photo.
I'll go up to the Image menu at the top of the screen and choose Image Size , which brings up the appropriately-named Image Size dialog box:. The Image Size dialog box is divided into two main sections, Pixel Dimensions at the top and Document Size directly below it. The Pixel Dimensions section tells us how many pixels are in our image.
The Document Size section tells us how large the image will appear on paper if we print it. If we look at the Pixel Dimensions section, we can see that this photo has a width of pixels and a height of pixels. In fact, at x , it may be too large to fit entirely on your screen!
But just because it looks nice and big on the screen doesn't necessarily mean it will print nice and big, at least not with any degree of quality. Let's take a closer look at what the Document Size section is telling us:. The Document Size section of the Image Size dialog box tells us two things - what the current resolution of our image is, and how large or small the image will appear if we print it based on that resolution.
You jumped to a second conclusion. Both you and Colin are wrong in this. Pixels are not dots and dots are not pixels. The average DPI for print is not It is DPI dots per inch. DPI defines the quality of the print. It is disappointing that Colin appears to be confused about his own use of terms in a teaching article. That means it use 8 horizontal dots in each line, and print 8 lines to get a single pixel.
Thus there are a total of 64 different dots of ink that make up the colour of a single pixel. These dots may not be the same size and are subject to dithering — relating the dots in one line to the colours of the dots in the previous and next lines. In other words, such a printer Epson and Canon will be laying down DPI dots of ink per linear inch of paper. Do the math. When I say is the average for print, I am referring to a commercial offset printing press, not a desktop printer. This is for designers as well as photographers.
And yes, I print to my Epson P at and let its software do the interpolation. Thanks Colin You are right, I am a photographer, not a designer. The point I was trying to make is that many print shops ask for a DPI file when in fact they should be asking for a PPI file to print at a specified size. So the poor client resizes resamples a perfectly sized original file but tagged 72PPI to DPI — and is disappointed when he gets a very large, very blurry print.
John, I see we are in agreement and basically saying the same thing. Your last statements about print shops and photo competition organizers organizers is spot on. That mentality was the inspiration for this article. And you are correct, you are giving the printer pixels, not dots. I just reduced the percentage size of the image until a handheld ruler became accurate with the photoshop rulers. It only took three tries to narrow it down accurately from an initial visual.
Your email address will not be published. In this Photoshop tutorial Im going to show you how to make a stamped metal effect. This is similar to DJI Mavic Pro drone, review pt2, tips and hacks. Portrait mode, hyperlapse, focus, handheld, calibration and more tips. Your questions How to make selections in Photoshop tutorial, Power user tips for the selection tools in Photoshop. Selecting shapes in Photoshop Signup for my best weekly updates and get access to e-books, brushes, presets, cheat sheets, actions..
Email Address:. The Ultimate Photoshop Resource. Customer Support Cart. Toggle navigation. Understanding Image Resolution in Photoshop for beginners Colin Smith Understanding Image Resolution in Photoshop for beginners This video and written guide explain what image resolution is in Photoshop.
Subscribe on YouTube:. And this image below is less than 10 inches. The difference is: DPI dots per inch is for Print. Ok, here we go,,, The only number that matters on a screen is the actual Dimensions in pixels. Remember the image of the butterfly? It was 10 inches wide. The butterfly is at ppi while the other image is only 82 ppi.
The original file we looked at is pixels wide width always comes before height This image is at screen resolution 82 ppi the resolution of the monitor, 82 pixels fits into a single inch of screen size The width of the file is So, to calculate dimensions This is useful if you know you need to create an image at a certain size and resolution. Figuring out the size you need for a new document Say you are going to create a poster at 10 inches by 7.
The height is 7. Working on screen You should never evaluate the size of an on-screen image in inches or cm, only in actual pixels. One last thing, you can use the resolution to display at actual size on your monitor Remember we talked about screen resolution? Why does that matter? Are these beginners tutorials or more accurately fundamental tutorials helping you?
Great to see you here at the CAFE! Pete Both you and Colin are wrong in this. Leave a Reply Cancel reply Your email address will not be published. Its fast and free! Grab a free Layer Blending Modes e-book, free tutorials, presets and more. No Spam Join. The more pixels per inch, the greater the resolution. Generally, an image with a higher resolution produces a better printed image quality.
Unless an image is resampled see Resampling , the amount of image data remains constant as you change either the print dimensions or resolution. For example, if you change the resolution of a file, its width and height change accordingly to maintain the same amount of image data.
Then change width, height, or resolution. As you change one value, the other two values change accordingly. With the Resample Image option selected, you can change the resolution, width, and height of the image to suit your printing or onscreen needs. Original dimensions and resolution B.
Decreasing the resolution without changing pixel dimensions no resampling C. Decreasing the resolution at same document size decreases pixel dimensions resampling. The file size of an image is the digital size of the image file, measured in kilobytes K , megabytes MB , or gigabytes GB.
File size is proportional to the pixel dimensions of the image. Images with more pixels may produce more detail at a given printed size, but they require more disk space to store and may be slower to edit and print. Image resolution thus becomes a compromise between image quality capturing all the data you need and file size.
Another factor that affects file size is file format. Similarly, color bit-depth and the number of layers and channels in an image affect file size. Photoshop supports a maximum pixel dimension of , by , pixels per image. This restriction places limits on the print size and resolution available to an image.
Printer resolution is measured in ink dots per inch, also known as dpi. Most inkjet printers have a resolution of approximately to dpi. Technically, inkjet printers produce a microscopic spray of ink, not actual dots like imagesetters or laser printers.
Printer resolution is different from, but related to image resolution. To print a high quality photo on an inkjet printer, an image resolution of at least ppi should provide good results. Screen frequency is the number of printer dots or halftone cells per inch used to print grayscale images or color separations.
Also known as screen ruling or line screen , screen frequency is measured in lines per inch lpi —or lines of cells per inch in a halftone screen. The higher the resolution of the output device, the finer higher a screen ruling you can use. The relationship between image resolution and screen frequency determines the quality of detail in the printed image.
To produce a halftone image of the highest quality, you generally use an image resolution that is from 1. But with some images and output devices, a lower resolution can produce good results. If you are printing an image on a nonhalftone printer, consult your service provider or your printer documentation for the recommended image resolutions. If you plan to print your image using a halftone screen, the range of suitable image resolutions depends on the screen frequency of your output device.
Photoshop can determine a recommended image resolution based on the screen frequency of your output device. If your image resolution is more than 2. This means that the image resolution is higher than necessary for the printer. Save a copy of the file, and then reduce the resolution. Produces a resolution that is the same as the screen frequency no lower than 72 pixels per inch.
The image is redisplayed in its approximate printed size, as specified in the Document Size area of the Image Size dialog box. Resampling is changing the amount of image data as you change either the pixel dimensions or the resolution of an image. When you downsample decrease the number of pixels , information is deleted from the image.
When you resample up increase the number of pixels, or upsample , new pixels are added. You specify an interpolation method to determine how pixels are added or deleted.
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