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08/07/2005 08:28:08 AM · #1 |
| When I save resize images for the challenge, should I size it to 72 dpi or 300 dpi? What difference does it make, if any? |
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08/07/2005 08:48:19 AM · #2 |
| Very quick answer: save at 72 dpi. |
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08/07/2005 09:22:33 AM · #3 |
Except we save at ppi (pixels per inch) not dpi (dots per inch). It doesn't seem to make any difference, for screen display, which figure is used, though. As long as it is saved to 640 pixels maximum dimension, the resultant image looks the same to me, even when I blow it way up to look at details. And it displays at the same size when "view" is set to "actual pixels". And when I resize a full-size, 300 dpi original to 640 pixels wide at 300 ppi and at 72 ppi, then save both as jpgs, the filesizes are the same if compression is set tot he same level.
So, unless I'm missing something, the ppi figure is meaningless for web viewing. I had thought it was important, but I just did a quick experiment and it does not seem to be. Anyone know what, if anything, I am missing?
R.
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08/07/2005 09:27:01 AM · #4 |
You're not missing anything. The whole dpi/ppi question is totally and utterly meaningless on screen unless you're setting image size by inches (or centimeters) rather than by pixel.
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08/07/2005 09:40:25 AM · #5 |
Originally posted by ganders:
You're not missing anything. The whole dpi/ppi question is totally and utterly meaningless on screen unless you're setting image size by inches (or centimeters) rather than by pixel. |
That's what I figured...
R.
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08/07/2005 10:39:18 AM · #6 |
Saving at 72 dpi will make a difference in the file size of the file. Or i'm wrong?
I tested, and doesn't make a difference in size. It's the same.
Message edited by author 2005-08-07 10:46:13.
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08/07/2005 11:14:54 AM · #7 |
Originally posted by Netwalker100:
Saving at 72 dpi will make a difference in the file size of the file. Or i'm wrong?
I tested, and doesn't make a difference in size. It's the same. |
Right. Surprised me too, at first, but it makes sense. The dpi/ppi figure is just a description to an arbitrary dimension; it doesn't actually effect how many pixels are IN the image. That part's controlled by the pixel dimensions you set into the field when you resize. And the number of pixels contained (breadth x height) is what makes the file size.
Robt.
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08/08/2005 12:41:07 PM · #8 |
Hi Robt,
I am amazed at your efficiency. You always come to my rescue, irrespective of the time I log on. Thanks again.
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08/09/2005 03:43:08 AM · #9 |
| From what they tell me, 72dpi is all that is necessary to view on screen, 300dpi is most often recommended for printing. Although I am also told that printing at 150dpi can produce an acceptable print, depending on the size of the print and how far away you are standing when viewing it. And for anyone who doesn't know , ppi (pixels per inch) coming in from your camera is the same as saying dpi(dots per inch) when it's going out to the printer. My 2 cents worth, please don't ask me for the technicalities of it, it took alot of people and a whole night to get me to this much of an understanding. |
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08/09/2005 03:50:23 AM · #10 |
To backup what bear_music says..
Dots per inch makes no difference on the screen, because it's a notional measurement.
It's the equivalent of asking what is heavier, a pound of nails or a pound of feathers.
To save images for the screen the only important element is the pixel size. If you want an image for DPC, make it 640 pixels wide/high and forget about DPI values and inch equivalent.
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