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BobtheEnforcer
2008-Sep-12, 08:46 PM
I'm not the greatest with photoshop, and I have a few questions if anybody is so inclined to help. If I have an image I took at 600 DPI and x2 magnification, and I double the image size (keeping resolution the same) what is my new magnification? How about if I do the same thing, but change the resolution? Basically I'd like to know how enlarging my images changes my original magnifications, with and without resolution change.

Thanks in advance!

PetersCreek
2008-Sep-12, 09:10 PM
Before I launch into explanations about image size, resampling, DPI and such, can you explain exactly what you're trying to do? Are you making prints? Are you just trying to display your images on a screen or webpage? Are you trying to zoom in on some detail within an image?

BobtheEnforcer
2008-Sep-12, 09:15 PM
Ok, I have a ton of pictures I took at 600 dpi, with varying degrees of magnification 2x - 5x. I'm making plates out of them for a scientific publication. The photoshop file (my plate) is set at 600 dpi as well. I move the pictures over, everything is the same dpi, and all my magnifications are correct. But I want to enlarge parts of some of the pictures. So, I want to know what my new magnification will be for those pictures after I make them larger. I need to do this so I can focus in on one aspect of the picture.

Thanks!

PetersCreek
2008-Sep-12, 09:26 PM
I'm assuming then, your plates will be sized to accurately represent the magnification factor used in relation to the actual size of the subject?

If you know what percentage of enlargement you want, I suggest using the Image>Image Size (Alt+Ctrl+I) dialog. Under the Document Size section, set your units to Percent and set whatever percentage of enlargement you wish. Leave (or set) the resolution to 600 pixels/inch, if desired. Afterwards, you can crop the image to publication size.

For reference, I'm using Photoshop CS2 but CS3 and any fairly recent version should work the same.

BobtheEnforcer
2008-Sep-12, 09:30 PM
Thats what I was planning...........but if I resize a 2x mag image @ 150% the change is just linear? In other words, at 150% the image would be 3x magnification? 200% = 4x mag?

PetersCreek
2008-Sep-12, 09:33 PM
Yep, that's it.