Changing to a Higher DPI

CR
Posted By
Cori_Roberts
Oct 27, 2005
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711
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Is it possible to convert an image that is at 96 DPI to a higher DPI such as 300 so that it will have a better quality or does the image have to be created at a higher DPI to begin with?
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C
chrisjbirchall
Oct 27, 2005
You can change the PPI (DPI is DOTS per inch and used when referring to printers) from 96 to 300 without affecting the quality – but the size will go down.

For instance: a 10×8" 96 ppi image (960×768 pixels) would become a 3.2×2.5" image at 300ppi – but it would still be 960×768 pixels!

You could resize with the "Resample" box checked and end up with a 10×8" 300ppi image. That’s 3,000×2,400 pixels.

Of course, you simply can not insert detail which wasn’t there in the first place – so where did all those other pixels come from?

They were "invented" by the resampling engine by guessing what the new pixels should be based upon the neighboring pixels. For a small degree of enlargement (say 150%) this can look okay. But as you become more ambitious the results begin to look pretty ropey.

When resampling up, always choose Bicubic Smoother, and when resampling down, Bicubic Sharper is the best choice. And NEVER resample more than once. Keep a master file at its generic size and go back to this should you require different sized images.

Hope this helps

Chris.
A7
aka 717
Oct 27, 2005
wrote in message
You can change the PPI (DPI is DOTS per inch and used when referring to printers) from 96 to 300 without affecting the quality – but the size will go down.

For instance: a 10×8" 96 ppi image (960×768 pixels) would become a
3.2×2.5" image at 300ppi – but it would still be 960×768 pixels!

You could resize with the "Resample" box checked and end up with a 10×8" 300ppi image. That’s 3,000×2,400 pixels.

Of course, you simply can not insert detail which wasn’t there in the first place – so where did all those other pixels come from?
They were "invented" by the resampling engine by guessing what the new pixels should be based upon the neighboring pixels. For a small degree of enlargement (say 150%) this can look okay. But as you become more ambitious the results begin to look pretty ropey.

When resampling up, always choose Bicubic Smoother, and when resampling down, Bicubic Sharper is the best choice. And NEVER resample more than once. Keep a master file at its generic size and go back to this should you require different sized images.

Hope this helps

Chris.

Where do you get bicubic (sharper and smoother)? Is that new in PhotoShop? It seems to be that standard bicubic would always be better and then sharpen or smooth after the interpolation … ?
A7
aka 717
Oct 27, 2005
wrote in message
Is it possible to convert an image that is at 96 DPI to a higher DPI such as 300 so that it will have a better quality or does the image have to be created at a higher DPI to begin with?

U can improve the quality but only to a point as
has already been said. It is always better to sample
higher in the original because you can always go
lower resolution. Of course, disk space, porcessing
time and transporting the files (email or whatever)
is a factor.
Good luck

Master Retouching Hair

Learn how to rescue details, remove flyaways, add volume, and enhance the definition of hair in any photo. We break down every tool and technique in Photoshop to get picture-perfect hair, every time.

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