View Full Version : How to find / change resolution

10-03-2006, 05:16 PM
Hi, I am trying to explain to a relative in the UK how to scan a photo and send it to me at a higher resolution. The Photoshop display Image Size shows the Resolution in pixels/inch and being a Mac user if I open his BMP files in iView Media it shows the same results.

Okay the image is from a Mass Card and should be about 5cm x 3.5cm in size. I have asked him to scan it at about 300 or 400 ppi. He has sent two files "one at 300 and the other at 600". As mentioned above in Image Size it shows the following information:

Pixels Dimensions 293.5K, Width 265 pixels, Height 378 pixels,
Document size: Width 9.35cm, Height 13.34cm, Resolution 72 pixels/inch,

Pixel Dimensions 1.15MB, Width 530 pixels, Height 756 pixels,
Document Size: Width 18.7cm, Height 23.67cm, Resolution 72 pixels/inch,

From this information is it correct to assume that they are both scanned at 72 ppi?

If they are 72 ppi then how would the files vary so much in Document size and dimensions when the actual scanned images is the same size?

What would he need to change to get the ppi up and the Document size down?

Can I affect any change in Photoshop to make the image less pixelated without ruining the original image?

Now the really strange thing is from his message accompanying the Photo's " For the Mass card small photos I have done two of each; one is at 600 and the other is at 300. I am afraid that I cannot do 400. I have tried 1200, but the pictures become too grainy."

The last sentence above is important, the image that is supposed to have been scanned at 600ppi is much grainier than the one scanned at 300 ppi. So at first it seemed silly to say that at 1200 ppi the image would be worse but in fact it is true.
I am still fairly new at all this but is seems as if the scanner is some how set to constrain the pixels per inch to 72 and as a result it actually increases the canvas size of the image rather than the resolution. But is this is the case how is it overiding the settings for 600 and 300ppi?

Any help on this matter would be greatly appreciated.

Perth Australia

10-03-2006, 05:47 PM
if he scanned at 72dpi, enlarging them after scan will definitely result in adverse effects..

but yeah.. i understand wad u mean.. some images/hard copies aint good to begin with, so the grains.. i would recommend scans at 300dpi to be sufficient..

settin the dpi is by the properties of ur scan windows.. there's a property for u to select the resolution to scan at..

10-03-2006, 10:58 PM
I think what they're probably seeing is grain. You want it. If it's digital, there's a serious error that neds to be investigated, but if it's film noise or grain, capture it in all its splendor and then fix it once you get it.