How to Crop Photos for Large Prints
If you've ever been disappointed by how large prints of your digital photos turn out, chances are that you're a victim of a "bad crop".
Since cropping itself is unavoidable (I'll explain why in a moment) you must take matters into your own hands and crop before you print.
This gives you a measure of control over which parts of the photo will get left out of your final print.
Why Photos Get Cropped
Below you'll see three versions of the same photo, and the red boxes show how the image will be cropped at different prints sizes.
The first one matches the dimensions of a 4x6 inch print, which also happens to be the same size and shape as your digital SLR sensor. The second shows the dimensions of a 5x7 print and the third is an 8x10 print.
The first thing that you'll notice is that these three rectangles are not the same size and shape.
It all comes down to the ratio between the length of the long side of the rectangle and the short side.
Let's start with the 4x6 print: if we divide both sides of the rectangle by 2, we get a ratio of 2:3. Ratios like this are commonly expressed with the long side first - in this case 3:2.
Now imagine that you'd like to blow up your 4x6 inch image to an 8x10.
Sounds good - let's pull out the calculator and simply multiply both sides of our 4x6 image by 2. And we get...8x12.
See the problem here?
At some point along the line, frame-makers the world over decided that 8x10 was a standard print size. But when you try to print your original 4x6 image at 8x10, your are going to cut off TWO INCHES from the original.
If your digital SLR camera had a sensor with a ratio of 5:4, this would be ideal for 8x10 prints (since you multiply 5x4 by 2 and get 10x8). But this comes with its own problem - with a sensor like this EVERY 4x6 print you made would get cropped.
Since 4x6 is a much more common print size than 8x10, many digital SLR camera sensors match the dimensions of a 4x6 print.
What To Do?
If you just send off your original digital files to your online printer of choice and choose 5x7 or 8x10 prints, the printer is going to have to make a choice about how to crop them.
Remember, cropping is inevitable - the only decision that you can make is whether you control the crop of leave it up to the printer (and some measure of chance).
The good news is that its fairly easy to pre-crop your images before you upload them to an online printing service.
How to Crop Photos
Most photo editing programs offer some type of cropping tool.
This tool can be constrained so that it mimics the dimensions of the final print size that you're going to make.
For example, you can set the cropping tool to crop as a 4x6, 5x7 or 8x10.
Here are the basic steps:
- Open the digital photo you're going to print in your image editing program
- Select the cropping tool and set it to the dimensions of your final print
- Crop the image as you see fit
- Save the image as a copy of the original
As far as this last step goes, I've found that it's quite helpful to add the dimensions of the crop to the image name. If your original digital photo is named DSC_5567.jpg, then a 5x7 crop of this image might be named DSC_5567_5x7.jpg.
Why is this naming helpful?
Once you've uploaded all of your images to an online printing service, the only thing they display is the filename.
Since the dimensions of the photo are right there in the filename, it makes it easy for you to remember how you cropped the image so that you order the correct matching print size.