Dots per Inch/Pixels per inch?

Lucian

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18 Jun 2012 - 10:51 PM

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Can anyone tell me if there is any difference. I am about to edit photos for web upload and my client has told me that the web designer requires the photos to be 800 pixels on the long side and saved at 72 dpi. DPI is only available in batch processing but i have opted to edit the photos individually so i will be rezixing them one at a time. If i save the photos at 800pixels by 600pixels at 300 ppi will they be ok for the website designer.

Thanks

Tooth (Critique Team)

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19 Jun 2012 - 1:03 AM

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1) difference between dots and pixels per inch..

they are often used interchangeably and for purposes of display on a screen they are effectively the same thing. However, in terms of printers and scanners they are not necessarily the same as each individual pixel can be formed by a number of different micro-dots ofink. So printers will advertise themselves as so many DPI, but the actual pixels per inch (PPI) may be much less.

2) Image size..pixels in the image - the number of pixels along width and height defines the number of pixels in the image which defines how much detail is in the image. This is the main if not the only thing you need to worry about.

3) and resolution..relates not to the size of the image in pixels, but the way in which these pixels are displayed. When you save a file with this information embedded, it is not affecting the file itself, but merely an add-on telling the display devie how big to display rthe individual pixels, or how many of them to fit into a given area of the screen. 72 ppi is a standard for screen displays..but if you give someone an image with the correct file sixe (number of pixels) and the "wrong" resolution, it's easy for them to change the resolution, as it's a function of the display device and not the image file itself.

Imagine an old-style black and white newspaper photo made of black and white dots. Seen at the normal size on the page, the dots/pixels are close enough together for you to see a seamless image. If you were to magnify the image you would see the dots - the image hasn't changed, but the resolution that it's displayed at has changed (less dots per inch ) and the size of the image as displayed has corresponingly increased.

This has all been a very laboured way of saying something quite simple, once it clicks with you...concentrate on the image size in number of pixels.Include the resolution if you want but don't lose any sleep over it

Hope you stuck with it and it's some help

Stephen

JohnParminter

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19 Jun 2012 - 7:17 AM

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Quote: If i save the photos at 800pixels by 600pixels at 300 ppi will they be ok for the website designer.

The web designer will be able to give you the answer, I think it will be much better to clarify with him/her directly.

User_Removed

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19 Jun 2012 - 9:39 AM

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Show your friend's web designer Jester's link.

We don't size our images in inches for the web we only use pixels. Just batch process 800 longest side.