Another 100% crop question

snerkler said:

I have used search but couldn't find the answer I'm looking for.

I'm just learning about photography and have a query regarding 100% crop.

On the Mac, if I open up an image using preview and click actual size from the menu I assume this is the 100% image size?

If I then use the crop function (select a section then choose crop from the menu) how do I ensure that I save this without compression? When I go to save there are several options. I assume jpeg will compress, but do any of the other options save without compression such as jpeg 2000, png, tiff?

Click to expand...

Yes "Actual Size" will zoom to 100%

JPEG 12 is fine, at that quality level compression shouldn't be an issue.

Assuming I can save without compression, having done the above would this be a 100% crop?

Click to expand...

Any crop will result in an image which can be viewed at 100%. The only variable is crop size - the crop needs to fit into the display space.
Usually the idea of a 100% crop is that it's small enough to fit on a web page or forum post for scrutinising.

If you had a huge display the size of a house, not cropping the image at all could allow the original image to be displayed at 100%.

On the other end of the scale, if you wanted a 100% crop for viewing on the web, typically anywhere from 640x480 to 1024x768px will fit at it's full size (not scaled down) in someone's browser.

On Macrumors, the maximum image size that will display at 100% (that is displaying without downscaling) is
780 pixels wide.

The "Actual Size" view does nothing more than let you see exactly how big the resulting crop will be, it doesn't really have an effect on an image becoming a "100% crop" it just helps you size the crop in accordance to the size restrictions of your image display space.

Hope that helps

If you don't want compression, use tiff.