Quote Originally Posted by clemmb
So if I take an image and crop exactly half of it away I should tell you this is an 18.6% crop?

No, you would say "cropped 50%". That is not the same as saying a "50% crop". It isn't an expression that is used normally anyway. When someone states that they are showing you a 100% crop then it is inferred that you are not seeing a reduction but the actual 1:1 pixel by pixel display of the original image. Cropped in the purest definition means "cut away". The term 100% crop is a variation of that expression. Most folks don't state whether or not their images are post cropped. i.e. If someone shows you a square formatted photo they don't tell you it's cropped square. That displayed image may only be 64% of the orignal photo. You, as the viewer will never know.


Quote Originally Posted by clemmb
That is what PS shows after the crop and I zoom to fit screen.

The 18.6% crop after a fit to screen is the zoom ratio of your monitor. You may be working on a 1280 x 1024. On my 1920x1200 it may report 25.4%. It's also dependent on the window size. Make Photoshop window only half of your screen and zoom to fit. The zoom percentage will go down even further.


Quote Originally Posted by clemmb
If I reduce an image for posting but keep the images as it was shot then I should tell you that it is a 9.2% crop?

No, because that is not a crop it is a reduction.


Also, remember there are ratio crops. Our cameras shoot in a 2:3 width to height ratio. To print this image we may choose to print on 5 x 7 or 8 x10 paper. It is at that time that we decide which part of the image has to be "cropped" inorder for it to fully fit on that size paper.


Does this help any?