Understanding Cropping and Resizing

by Micah Walter

cropping.pngI really like the way Aperture deals with cropping and resizing on export. For some reason it makes perfect sense to me. However, many people I talk to just can't get their heads around it.

Let's say for instance that you want to take one of your full resolution images, crop it, and make it 500 pixels wide for use on the web. In Photoshop, it's a pretty straight forward process. You simply use the crop tool to make your desired crop, and then change the image width to 500 pixels in the Image Size dialog box. If you have clicked Constrain Proportions, all you have to do is click OK. Of course, you will have to be sure to save that image as a new file in order to preserve the original full resolution file.

In Aperture things are slightly different. Because Aperture is a non-destructive image editing application, you can make as many crops as you like without affecting the image itself. If you crop an image, you can easily bring it back to the original crop, simply by deselecting the checkbox next to "Crop" in the Adjustments Inspector or HUD. You can create an individual crop for as many versions of an image master that you would like, and any of these crops can be removed or changed at any time.

But the confusion seems to be in the way that Aperture deals with resizing. The truth is, unlike Photoshop, where you create the final image size within the program itself, Aperture doesn't do any image resizing until you export a Version. So, I often find novice Aperture users struggling with the crop tool, thinking that this is where the pixel dimensions should be placed.

When you open the crop tool you have the option of either making a freeform crop, or entering some numbers with which to constrain the crop tool. These numbers can be selected from the drop down box of Common Sizes, or you can enter them yourself.

What I find many people misunderstand is that the numbers in the crop tool relate to an aspect ratio and not actual pixel dimensions. This can be a little confusing for some people, especially those who are used to Photoshop, and those who are somewhat new to photography.

So, here is a quick tip that might help make things a little easier. First, set up a new Export Preset in Aperture. To do this, simply click the Aperture menu in the top menu bar and select Presets and then Image Export. A dialog box will appear and on the left hand side you will see a list of presets. Pick one that is fairly generic, such as "JPEG Fit Within 640x640." This is one of the presets that comes packaged with Aperture, so unless you have for some reason deleted all of these, this one should be there waiting for you.

Make a copy of this preset by selecting the present and then clicking the "+" button on the bottom left. Once you have created this new duplicate copy of the original preset, rename it to something along the lines of "JPEG Custom." Next, drag the preset up to the top of the list and click OK.

Once you have created this custom preset, a really quick and dirty workflow can go something like this:

  1. Crop you image in Aperture using the crop tool so that is simply looks the way you want and contains the portion of the image you care about.

  2. Right click the image and select Export->Version.

  3. Select the drop down box labeled Export Preset. You will see your "JPEG Custom" preset at the top.

  4. You can either use the current settings (fit within 640x640 from the preset you copied) or scroll to the bottom to where it says "Edit", and quickly make a change to the export dimensions.

Don't think of this preset as a preset. Just think of it as a way to set up custom dimensions on the fly, right before you export your images. You can put in any dimensions you want, and change them at any time. Whatever setting you select will remain present until the next time you change them. So, if you find yourself using the same numbers over and over again, then it's time to set up a permanent preset for those numbers.


David Medina
2007-07-03 21:39:47
Hey Micah, would you or Derrick do a series on the best way to do highlight recovery and it's advance tools? Any rumors as far as when is the next update for Aperure? New features?

Thanks for the great job you guys are doing in Inside Aperture.

2007-07-04 03:27:53
thank you for the cropping info, I have been following closely for months and in fact the lightroom/Aperture comparison made me jump in and I love Aperture and am unlearning photoshop stuff.
One question on croping, how does one crop a specific size like 747 x 499 ?? 72 dpi ? I guess this is where PS was awesome. Thanks and keep it coming I love the daily tips
Micah Walter
2007-07-04 06:13:15
This is sort of what I wanted to try and explain in this post, but you have pointed out a pretty simple issue in Aperture. In order to make a specific sized box you have to go through a two step process. First, you need to figure out the aspect ratio for the crop you want. It would be so much easier if Aperture let you type in any numbers into the crop tool, but they limit the numbers to 40 for some reason.

To figure out the aspect ratio for your example, just divide the width by the height. So, 747/499 would give you 1.4969... Or about 1.5. This means that you could put into the width 1.5, and 1 into the height to get the aspect ratio you want. This is somewhat approximate, and if you entered 1.49456 Aperture would just round it back to 1.5.

Once you have 1.5 to 1 in the crop tool, just make your crop box as usual. When you go to export a version, set the width and height to fit within your dimensions of 747x499, and Aperture will pick the shorter dimension and adjust the other one.

In your example here is my result. I set the crop tool to 1.5 to 1, made my crop and exported it using a fit within 747 and 499 pixel box. I also set the output res to 72 dpi, though this doesn't really matter. My exported image resulted in an image that was 744x499. Notice the width is slightly shorter because of the approximation.

I really hope in the next version of Aperture that they allow you to put in any numbers in the crop tool. This would make things very simply. Just enter your pixel dimensions, and have a preset set up to output the original size, and you would be done....

Hope this helps.

2007-07-04 07:31:06
micah, thanks for the quick reply and you made it so clear I need the next version of Aperture, so i continue with PS 3 for a while. My specific sizes are for a web page so i might as well crop in PS. I agree Aperture needs this so then everything can remain within the program as intended.
Much clear with this example thanks. T
Micah Walter
2007-07-04 07:37:34
I wouldn't let this one little issue stop me from using Aperture. In fact, Aperture works really nicely in tandem with CS3. You can send your images to CS3 from Aperture as PSD files and Aperture will keep tabs on the PSD doc by adding it to a Stack with the original Master RAW file. That type of organization is really sweet.

With Aperture and CS3 you could set up a pretty easy workflow where you exported all of your images as full res, or even half res, to a folder on your desktop, and then use a CS 3 action to create the exact crop on all the frames at once for your web layout. (If they are all the same dimensions.)

You could probably also set up an Automator Workflow to do something similar. An Aperture and CS3 combo is pretty nice, and it's what I use as my two primary image applications. (Well, sometimes I use Preview too!)


Francois Couderc
2007-07-10 13:46:42
I just want to remind you that Aperture can show any picture's proportions in the navigator when you see the pictures as a list instead of the thumbnails.


Len Smale
2007-07-28 11:54:28
The problem with the Aperture crop tool is not the slightly arcane UI, but the fact that it only lets you constrain the proportions to common sizes, not an aspect ratio of your choice. This makes it very difficult to crop an image to a precise aspect ratio to, for example, fill the splash screen of a nuvi GPS so that it does not have black bands.
You basically can find the max H/W combination and use a claculator to type it into the Crop HUD, but what a pain and not up to Apple's usual standards of UI engineering.
- G
2007-11-17 16:04:46
I've noticed that some of my crops of 5 by 7, when exported to PS, is off by 0.01 inches. How can I ensure that my aspect ratios are maintained?