Resizing Images in Adobe Photoshop CC

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Resizing Images in Adobe Photoshop CC

Photo shows two Image size dialog boxes with resolution values of 100 and 300.
The Image Size dialog box is the unsung hero when it comes to manipulating the resolution or or size of images.

One of the “evils” of working with digital images is resizing them. For example scaling an image can result in a  “pixelated” image . This is usually due to how images are scaled. The image isn’t made bigger. The pixels are made bigger which results in pixelization and distortion.

 Another common cause for this is increasing the image resolution from, say, 72 ppi to 300 ppi.  Not only is the image made physically larger but the image may look washed out, soft or the colors aren’t quite right. This is usually due to a process called interpolation. When you increase the resolution you are adding pixels to the image and, in many cases, the computer makes the wrong choices. For example, assume you double the resolution of an image. If a green pixel and a red pixel are beside each other they will be moved apart and two new pixels will be added between them. The question is what will be the colors of the two new pixels?  When I ask this in my classes I can always expect a dozen different answers. The students are doing exactly what the computer does: guessing which colors are correct.

This has not gone unnoticed by the Photoshop engineers. In the latest versions of Photoshop CC they came up with a new option for upsizing images (making them larger using the Image Size dialog) by using a clever new algorithm for upsizing an image while maintaining more detail and sharpness than ever before.

Let’s try it out.

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How To Use The Image Size Dialog Box in Photoshop CC

The Image Options dialog box is shown.
The magic happens with a rather complete number of choices in the Image Size dialog box.

The first step in the process is to select Image>Image Size. This will open the Image Size Dialog Box. In this case the image is 1420 pixels wide, 921 pixels high and has a resolution of 100 pixels/inch. (ppi). The plan is to increase the image resolution to 300 ppi, which is a standard High Resolution value commonly used for print.

At the top of the dialog box is a dimensions pop down which let’s you change the measurement system for the image.

  •  The Fit To pop down offers you a number of preset sizes.
  • The Width and Height values can be manually changed by entering new values and the pop down let’s you choose the measurement system.
  • The Resolution value can be manually changed and you change the measurement system to either Pixels/Inch or Pixels/Centimeter.
  • The Resample pop down is where the magic happens. The choices here will have a huge effect on image quality.
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How To Use The Resampling Options In Photoshop CC

The resolution value has been changed to 300 ppi.
Set the resoution and then return to image to its original size.

The first thing to do is to select the Resample checkbox and to select Preserve Details (Enlargement) from the pop down. This will also open a Reduce Noise slider. This appears because, when images are enlarged, noise will be introduced into the image. This slider, when used cautiously, will smooth out the noise.

The next step is to enter your new resolution value. When you do this the physical dimensions of the image will change and the image in the Preview window will look pixelated. This is due to the resizing of the image. Reenter the original width and height values.

Click and drag the image in the Preview window to look for artifacts. If you find them, use the Reduce Noise slider to remove it or make it less noticeable.

One final point, if you find yourself using the same values on a regular basis you can make the process smoother by saving those values as a preset by selecting Save Preset from the Fit To pop down.

The Image Size dialog box is especially useful when imaging for mobile. Devices all have varying screen resolution and image scaling requirements. Following this step – Select Preserve Details (Enlargement) and then setting the image dimensions removes a common pain point from the mobile imaging process.