Currently Being ModeratedMar 1, 2013 3:22 AM (in response to ribbo39)
Once you take a screen shot (cmd shift 4) you are essentially taking a picture of your screen.
Please forget doing this as this is not how you crop an image in preview.
The best way to go about doing this is to use your scanner to crop the appropriate area before it scans. Most scanners can do this with the included software.
if this is not an option, then use preview to crop your image.
expand preview all the way out so you see these tool options on the upper right corner of Preview.app.
first click the box with the dots (the one on the left) to select the area you want to crop. Then select the second circled option that looks like two right angles merged together to crop the image to the selection you just made.
What you were doing is taking a screen shot.
taking a screen shot has a resolution of 72dpi and should be used to trouble shoot issues or show someone something on your screen, like I have done with this example.
Currently Being ModeratedMar 3, 2013 1:24 PM (in response to TheSmokeMonster)
Thanks for you reply and sorry for delay in getting back to you.
What you have suggested works very well apart from one aspect. If the document is not square or rectangular then parst of the image are deleted. Here attached is a part of the document showing an area - hopefully it will fit.
The other point; is it possible to change the resolution in a screenshot from what you say is 72 dpi?
Currently Being ModeratedMar 3, 2013 7:33 PM (in response to ribbo39)
Images can only be rectangular. Even with screen shots, that's the case.
What about cropping an image this way doesn't work for you? I didn't see the attachment.
No, 72DPI images can't be upscaled, or enhanced, that's only in the movies. What would happen is you blow up an image and it's pixels, making for a really jagged looking image because it can't re interpret the information.
Having said that, photoshop is pretty good at raising the DPI with less sacrifice to the image.
I'm glad I could be helpful.