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54

I like the accepted answer, it has good advice, but I thought I'd expand on it a bit. For wall sized graphics and large banners (e.g 3m x 5m), what is an acceptable PPI/DPI for print. Here's definitions, so we know what we're talking about. DPI = Dots per inch = units used to measure the resolution of a printer LPI = Lines per inch = The offset ...


34

In general you should use vector graphics in the artwork wherever practical, and deliver final artwork to the printer in PDF or other vector format. Your finished print will then be limited only by the output resolution of the print device. This is particularly important with text and line art — visible rasterization in the finished print will be very ...


22

The only definitive answer to this question is: Ask your vendor. Every vendor, every printer, every t-shirt maker, etc will have their own particular preferences as to how they want to receive files and how they want them set up. Discussing this with your vendor before you begin is crucial to ensure that the process goes smoothly. The general rules of ...


21

File > Save for Web and then enter the pixel dimensions by clicking the Image Size tab on the right of the Save for Web window. Or am I not understanding you correctly?


18

The PPI doesn't really matter if you use pixels as units; 1000x1000 pixels at 300 or 72ppi will still be 1000x1000 pixels. But when you change the units to inches, then you'll notice one is smaller than the other; there will be be more pixels per inch as the name says. As you mentioned, PPI is more for printing, but it can also now be used as a reference for ...


17

Grande format resolutions, as various folks have pointed out, depend on viewing distance. Several answers refer to line screens, but technology has moved on. Very few, if any, grande format jobs are printed that way, and in any case, none of the answers indicated how to translate from PPI (dots) resolution in Photoshop to LPI (lines of dots at different ...


17

I've always thought DPI was somewhat of a misnomer... It really only applies if you are printing an image, otherwise, well, pixels are pixels. For an image on a site, well, it really doesn't matter, just get as many as possible, to fit the required size. Printers vary somewhat, but around 300 DPI is usually a good rule of thumb for anything around the size ...


14

A pixel (the word was originally coined, iirc, by IBM and derives from "picture element") is the smallest indivisible unit of information in a digital image. Pixels may be displayed, or they may be printed, but you can't divide pixels into smaller pieces to get more information. How many channels and bits per channel make up one pixel is the measure of how ...


11

Using File → Save for Web and entering the dimensions will do what you're after. Also, Illustrator uses vector scaling, so the results are better than if you tried the same thing in Photoshop — entering dimensions that don't match the document in Photoshop means the image will be bitmap scaled. Please note that you have to click Apply after changing the ...


7

I recently read jrista's marvellous q&a from photo.stackexchange. While the question is titled "How do I generate high quality prints with an ink jet printer?" it covers DPI & PPI relationship to quite an extent and has real-world print examples. Current Q&A contents: Summary Detailed Explanation Empirical Studies: Does PPI really matter? ...


7

DPI (digital dots or pixels)/PPI defined: 300 dpi/ppi = 300 pixels used for every 1 inch line of ink coverage. 1000 pixels will yield a 3.3333 inch line @ 300 dpi of resolution DPI and PPI have been used interchangeably (though not always accurately) since pixels entered the printing industry. DPI comes from halftone/screen dots in offset printing. If a ...


7

If the printer is asking for 600dpi, it means [he] either didn't understand the question or there has been a failure to communicate. 600dpi (dots per inch) is the resolution at which your billboard will be printed. There was a time, in the Long Long Ago, when that would have been considered pretty high-resolution stuff -- I remember having posters printed ...


7

Should my images be saved at a specific PPI? No. iOS ignores PPI (pixels per inch) stored inside images. However, the pixel dimensions of your images do matter, so make sure you get those right. It’s also important to ensure your 2× images are exactly double the dimensions of your 1× images and that elements within the image are in the same ...


7

Well, where I come from 400x600cm is 4x6 meters. :-) 30 dpi for final output is more than enough for a billboard of that size. It's not unusual for final output to be 12-15 dpi in this context. The usual professional billboard workflow in Photoshop is to build the image at a small scale with high ppi (e.g., 4x6cm @ 300 ppi), but in this case you can work ...


7

1: No. The printer will print the image using the most appropriate resolution it has at its disposal. This is why we have drivers. 2: Short answer, yes. Long answer, it depends. Depending on how the printer software uses the word "quality", the printer may use more or less ink. In some cases, a "draft" quality will use less ink (and produce a lower quality ...


6

Did you change the pixel dimensions as well? DPI is typically meta-information to tell a printer how large to print the image. It normally doesn't have any affect on the actual pixel dimensions of the image. If that's the case, than the difference is likely that you saved the image with a high JPG compression setting. The best way for us to determine ...


6

How close are you going to view the 4' canvas? Is reducing the dpi really going to adversely affect printing on a coarse material like cotton or silk. Thats coarse relative to smooth glossy photo prints, for example. See this recent question: What DPI should a large format artwork for print be done at?


6

iPhone4 retina displays are 960x640 with 326 dpi (ppi). http://en.wikipedia.org/wiki/Retina_display#Display


6

By default browsers display images at the native screen resolution i.e. one pixel in the image maps to one pixel on the screen. The browser ignores any resolution value defined within the image file. You can of course override this behaviour by specifying a width and/or height value for the image, either as parameters on the <img> element or as CSS ...


6

As a general rule, when your working on a screen, forget about physical dimensions and resolution (PPI). All that affects the size you see something on screen is its pixel dimensions. Your screen doesn't know what an inch is, all it knows is pixels. In your examples: 1×1 inch image at 72PPI is 72×72 pixels. 1×1 inch image at 27PPI is 27×27 pixels. Your ...


5

Specifically on PPI for web or other on-screen images: 72PPI (or 75, or 96) is a myth. Yes, there is a figure which applications use to decide how many pixels to use to render fonts specified in points, but this hasn't got any relevance to images, other than: if your Photoshop document is 72ppi, it doesn't matter if your font units are set to points or ...


5

ppi = pixels per inch = typically used as a measurement for screens (the iPhone 4 has twice the ppi as the iphone 3) dpi = dots per inch = typically used as a print measurement and refers to the number of pixels in the image that will be used to render 1" on paper scaling = this is a loaded term and why the answer isn't simple. For raster images, you can ...


5

800 pixels by 800 pixels and need to convert them in Photoshop to 72 ppi for web use (at the same size: 800px by 800px). There's no conversion to do. If they're 800 pixels by 800 pixels, that's it, they're the size you need. However, 300ppi at 800px by 800px is like a 2.3" by 2.3" picture, so are you sure the files are currently at 800pixels by 800pixels? ...


5

Other answers have more than adequately explained resolution, so I'll explain density, which has a VERY different meaning in the graphic design world. Ink density is the total area coverage of paper by the printed ink dots, from 0-400% (100% each for CMYK), and this is important because depending on the printing process, only 250-350% is available for use, ...


4

I think Jan Steinman was close with his angular explanation. The DPI table is good as well but in the end it all comes down to pixels not DPI for photographic images. Forget DPI, a good rule of thumb is that across your field of view your eye can not see more than 8,000 pixels. Therefore you should not create a bitmap image of more than 8,000 pixels across. ...


4

Roger's right. You WILL NOT be in trouble at 150 ppi for an inkjet-type print process, especially at that size. But let's pretend that you can't change the 300 ppi requirement. The problem you are running into is memory, and it may be an impossible hill to climb without upgrading your hardware, but here are some basic steps that can mitigate the problem: ...


4

As Horatio says, if it looks good, it's probably fine. There are two schools of thought on upsampling: One says, "Never, ever upsample"; the other says, "Hey, what the heck, upsampling rocks." In almost all cases I side with the former. Upsampling adds nothing but "best guesses" to the image. It specifically doesn't add any image information (I don't care ...


4

If you want your photoshop to match the pixels on the Kindle, then your PSD file should be 1024x600 pixels. DPI is a measurement of the pixel density on the device itself and has no real bearing on your PSD file.


4

You can use the build in Preflight function. [I don't know when it has been introduced but its there in Acroboat 9 Pro and above] Advanced > Preflight [Keyboard Shortcut Shift + Ctrl + X ] Have a look at this video to see what I mean: http://www.mattbeals.com/videos/Adobe/ShowImageRes/ShowImageRes.html There are also other plugins and stuff, but as ...


4

PPI means "pixels per inch," and is a web display measurement. DPI means "dots per inch," and is a print measurement. If your Image Size dialog box reads "300 pixels per inch," you're fine. However, if you're starting at less than that, most likely you cannot arbitrarily make the PPI larger without sacrificing quality. (Depends on how far you're sampling ...



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