What does 100% crop mean?

I know what cropping is but I cannot quite get what a 100% crop means. I probably have done it several times but.... Anyone?

MALI

Its like you have a massive high res image and in PS use your rectangle tool to select a small portion , then copy paste that portion into a new document , and print or add to a website , it maybe be only an eye or such out of the high res but will end up 800x600 or something on a monitor , that piece you cropped out would be at 100% res or 100% crop .
Rod

In the image editing software of your choice view your image at 100% - in PS either select View/Actual Pixels or double-click on the Zoom Tool. Then crop out a section of the image and "Save As" to another file.

The size of that crop does not matter? Like, is there a 85% crop as opposed to 100% crop? Why 100%? Or in other words, what makes it 100% crop? Or still in other words, why do we call it 100% crop rather than just crop?

MALI

Because you view it, and crop it, at 100% magnification. The term 100% crop is short for a cropped portion of an image viewed at 100% of its actual size.

So let me see if I get it right?

You are looking at a picture in Photoshop in Actual Size, which makes it 100%, and then you crop a part of it. This is called 100% crop, correct?

If on the other hand, you are looking at the same picture in Fit on Screen mode, and cropping a part of it, that is not 100% crop.

Did I get it right?

MALI

Yes.

Phew, I got that one out of the way. Thanks, people.

Now I can stop wondering what the heck it is while people are talking about it. Let's move on...

MALI

Not exactly.... It doesn't matter what size you have on your screen when you do the cropping. It could be the whole image. The key thing is that you do not change the resolution of the resulting crop by re-sizing prior to saving as a separate file. The resulting new file will have precisely the same pixels making up what's left of the image as that portion of the original image.

The whole purpose is so that folks on the forum (or whoever is viewing the crop) can see all of the detail in the original image without having to post the whole image (which can be huge and take a long time for folks to download).

I think it's also good when doing a test print of a large image, you just do a 100% crop of an area and then print that to see if it is going to look good.

A much better, more detailed explanation Skip. I certainly left off the part about not resizing the image as I thought it was implied, but one should never assume that it will be apparent.

basically, 100% crop would be (on your monitor) 72dpi at however big the image is.

a 100% crop of an image on print would be somewhat like a test strip you get from professional labs before printing large images.

what would dpi have to do with it?

I see a lot of confusion here about something that is very simple.
If the image is not resampled, then that image or any portion of that image is a 100% crop. So the important aspect of it is that during whatver operation you do to that image it must not be resampled.

All of that other stuff, such as magnification and re-sizing and what the dpi setting is, etc., is all irrelevant.

Did I get it right?

Exactamundo, Bob!