72 or 96 dpi?

User 414501 Photo


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I understand that the internet is getting faster and monitors are getting sharper. Many people are now saying that web graphics should be saved at 96dpi... but it's not that clear. Different people seem to be saying different things, and the people in the Photoshop forums say that dpi doesn't matter at all!

It really doesn't matter what dpi you save as for internet viewing. The browsers ignore it. All that matters is number of pixels wide by number of pixels tall. A common screen "resolution" is 1024x768. I usually size my pictures on the internet to 500x400. I do tag them as 72dpi, but occasionally I forget and leave them tagged as 4000dpi (which is what my scanner's native resolution is). Theoretically, this means that the image is 1/8 inch wide (pretty darn small), but guess what... Internet explorer doesn't display it any differently...


Got that from here:

http://photo.net/digital-darkroom-forum/004WUv

And then you have the people who say web graphics should actually be saved at 120 or even 180 dpi.

Anyone have thoughts on this? I am confused... :/

Chad Spillars
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User 364143 Photo


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Everything I have read on this matter, and it has been discussed here before, is that 96 dpi is fine for the web. Higher dpi is for printed photos. But I am no authority on the subject. I used to save all my web graphics at 300 dpi but now just use 96 dpi.
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User 414501 Photo


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Here is the answer I got when I posted this same question in the Adobe Photoshop forums:

If you are saving for web use, only the pixel count matters. The dpi setting is for controlling prints. You can always set the dpi to whatever you want, however, by clicking on Image > Image Size and in the Document Size portion of the dialog box change the resolution.


But I have been told that most of the newer monitors are set to 96 dpi, why is why I want to optimize my graphics at that setting. If dpi doesn't matter, as I've heard many people say, then why even use 72 dpi? Why not set all images to 10 dpi or even 5 dpi? Imagine how fast the site would load! I'm not trying to be rude or sarcastic. Just looking for answers...
Chad Spillars
"Look I finally made myself a signature!"
User 463058 Photo


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Chad Spillars wrote:
Different people seem to be saying different things, and the people in the Photoshop forums say that dpi doesn't matter at all!


They're right, if you are talking about the web, in which case the dpi of images is irrelevant.
User 463058 Photo


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Chad Spillars wrote:
But I have been told that most of the newer monitors are set to 96 dpi, why is why I want to optimize my graphics at that setting.


That's Windows' default setting, but I don't know of any monitors that are really 96 dpi. Mine is set at 96 dpi, but it's actually more like 100 dpi, someone with a higher resolution monitor of the same physical size would have an even higher dpi.

Chad Spillars wrote:
If dpi doesn't matter, as I've heard many people say, then why even use 72 dpi?


It's a DTP and printing thing. I never even pay attention to dpi settings because they have no bearing on my web work. An image's dpi is also ignored when printing a web page containing that image.

Chad Spillars wrote:
Why not set all images to 10 dpi or even 5 dpi? Imagine how fast the site would load!


A 500 x 300 pixel image will load at the same speed at any dpi setting you use for it. And it will always appear the same size on your screen, regardless of the screen's dpi setting. It's size will only be affected by changes to your screen resolution.
User 414501 Photo


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Wow that's interesting. So the only reason to set web images at a higher DPI (96 or 120 for example) is if you want to look a little better when/if someone tries to print our your web page.

Here is an interesting article that explains all this and backs up what you, Cary, said very well. This guy posted three images on his web site using the EXACT same dimensions, but different DPI: one is 7dpi one is 72dpi and one is 720dpi... they all look exactly the same on the screen! You can't tell the difference:

http://www.scantips.com/no72dpi.html

more good explanation here:

http://blog.patyuen.com/lessons/the-72-dpi-myth/

and here:

http://apptools.com/examples/dpi.php

Thanks everyone for your help. I was seriously thinking about changing the DPI of all my images to 96 because someone told me that is the new standard for web, but now I understand that person was mis-informed.

If anyone has any more information to add please do so! I need all the knowledge and wisdom that I can get!
Chad Spillars
"Look I finally made myself a signature!"
User 463058 Photo


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Chad Spillars wrote:
So the only reason to set web images at a higher DPI (96 or 120 for example) is if you want to look a little better when/if someone tries to print our your web page.


In the case of printing web pages, image dpi won't affect the quality of the images when you print them. The only way to improve the image quality is to increase the information in the image by increasing the dimensions of the image which gives you a larger image on your page.

There may be a way to improve the image quality when printing, but I never tried it, so I don't know if in fact it would work. In theory, if you wanted a 500 x 300 image on your web page, but you wanted it to print at higher quality, you could embed a higher quality image, say 1000 x 600, and size it in the html to 500 x 300. This will look lousy on the screen, but perhaps nicer than a 500 x 300 image when the web page is printed, unless the computer just uses the screen rendering.

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