A lot of people use the terms "resizing" and "resampling" interchangeably but if you do so, you may unwittingly compromise the integrity of your image. Though the choice to resize or resample your image is handled by the Image Size dialog box in which there is a single checkbox option at the bottom, it is important you select the right one. So, what is image resizing, and what is image resampling?
When you select image resizing, you are essentially telling Photoshop that you would like to keep the image's pixel dimensions but change the size of the image for print. In Photoshop lingo, "resizing" refers to the changing of the document size of the image. Image resampling, on the other hand occurs, when you physically change the number of pixels in an image.
Why resample when you can merely resize? Resampling essentially allows you to pick and choose which details you would like to include in your image. When you downsample, you delete information and therefore detail from your photo or image. However, when you upsample, you add pixels. Photoshop refers to upsampling as interpolation.
Interpolation means that the program of your choice analyzes the colors and details of the original photo and creates new ones, which are then added to the existing details. The reason one might perform this technique is to create a natural-looking supersized image without artifacts.
There are several interpolation techniques you can use. Which is best for your image depends on how much time you have, how big your original file is, and how precise you want the final image to be. The six methods are as follows:
- Bicubic Automatic
Bicubic is the slowest but most precise method. Nearest Neighbor is the fastest but least precise. Bicubic Smoother is ideal for upsampling while Bicubic Sharper is best for downsampling. Bicubic Automatic is great for both.
Practice both upsampling and downsampling on high quality images. Check out our gallery
for the perfect image on which to test your skills.