[Frameworks] DPI

[Gene Youngblood]

Thanks very much, Buck and Aaron, for your informative explanations.

> On Jul 1, 2015, at 11:56 AM, Aaron F. Ross <aaron at digitalartsguild.com> wrote:
> 
> No, Gene, that's the absolute number of pixels, not the size of the image when  printed.
> 
> "DPI" is the number of dots per inch. It should actually be referred to as "PPI" or pixels per inch. (DPI is number of printer ink dots, which is different from the size of a pixel.)
> 
> PPI is a setting in the file header that tells a printer how big a pixel should be printed. The PPI setting is completely independent of the number of pixels.
> 
> Looking at an image on your screen, zoomed at 100%, you will see the image pixels mapped one-to-one onto your display. You will not be able to visually ascertain how large that image will be when printed. When zoomed at 100%, a 300 pixel image @ 300 ppi looks the same as a 300 pixel image @ 96 ppi.
> 
> The PPI setting also can be used to emulate the size of a printed page (Photoshop zoomed to "actual size") but this is often wrong because the app doesn't know enough about the display device to be accurate.
> 
> An image that is 300 pixels wide @ 300 ppi will print out to be one inch wide.
> 
> An image that is 300 pixels wide @ 96 ppi will print out to 3 and 1/8 inches wide. ( 300 / 96 = 3.125 )
> 
> I wrote an article explaining this in more detail.
> 
> http://digitalartsguild.com/index.php/resources-menu/articles-resources-menu/71-digital-images-101?showall=&start=3
> 
> Regards,
> 
> Aaron
> 
> 
> 
> At 7/1/2015, you wrote:
>> Friends, am I assuming correctly that when you “get info” about the properties of an online photo, “dimensions” (i.e., 400 x 500) refers to DPI? _______________________________________________ FrameWorks mailing list FrameWorks at jonasmekasfilms.com https://mailman-mail5.webfaction.com/listinfo/frameworks
> 
> 
> --------------------------------------------------------------
> 
>      Aaron F. Ross, artist and educator
>      http://dr-yo.com
>      http://digitalartsguild.com
> 
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