When, Why and How to Crop Actual Pixels in Adobe Photoshop CS6

Photoshop CS6 has new redesigned and improved Crop tool with new features and I am very excited about that. In this tutorial I want to discuss one feature that is missing as in previous versions. That feature is to crop actual pixels with defined dimensions. I mean to set in advance desired dimensions like 480x360px and to crop without any pixel interpolation or resolution change.

Cropping pixels without interpolation
If you have question: what is wrong with interpolation? my answer is nothing, it works nice as everything else in Photoshop but… Interpolation means changing pixels (DIGITAL IMAGE INTERPOLATION). As you may know there is an option to set interpolation method when resampling images from the Image Size dialog, to set default interpolation method in Preferences dialog (Ctrl + K is the keyboard shortcut) and new in CS6 for Free Transform mode. When cropping images Crop Tool will use the interpolation method specified in the Preferences dialog. By the way new Photoshop CS6 has new option: Bicubic Automatic. Bicubic Automatic means that Photoshop will automatically detect and use method of interpolation which is best for you based on new versus old dimensions.

When to skip interpolation
You should skip interpolating pixels whenever you deal with images already resampled and saved with lossy compression. During compression, image will lost details. Let's say you are working with an image already downsampled which have lost some details when resampled and some details thanks to JPEG compression. Another interpolation and compression won't make the image looks better, at least you can skip interpolation of pixels.

Off course, this is true only if you can trim some area without resampling image, for example: when you have 560x420px but you need 480x360px and area to be trimmed or excluded is not that important. Another situation is when you have a bigger image of what you need and important details you want to keep falls into desired dimensions for output.

How to crop actual pixels
Because you cannot grab actual pixels with Crop Tool in Photoshop although you can crop in fixed size which is one among many options, for that purpose use Rectangular Marquee Tool. First, off course select this tool from the toolbox or press letter M–keyboard shortcut.

Next step is to set style to Fixed Size in Options bar and to type, dimensions for Width and Height followed with measurement unit. After typing exact dimensions click once on the image and you will have selection which will select actual pixels in defined dimensions regardless of magnification level. At this point you can go to Image > Crop as in previous versions or to use new in CS6 option and to activate Crop Tool. Press letter C on your keyboard or click on Crop Tool icon in toolbox. The Crop Tool marquee will appear with the area to be trimmed shaded.
While selection is active press C on keyboard
While selection is active press C on keyboard and Crop tool marquee will appear based on selection

Press Enter/Return on your keyboard and overlay will appear. You can cycle through different overlays using letter O–keyboard shortcut or to click inside the selection and to move it around. One important option is to pay attention: uncheck Delete Cropped Pixels and Photoshop will automatically convert Background layer to normal and hide unwanted pixels instead of deleting it so you can later change what is visible on the image and what is cropped or hidden. Press one more time Enter/Return or confirm on Commit current crop operation check-mark in the Options bar.
Uncheck Delete Cropped Pixels (circle) and confirm crop on checkmark (arrow)
Uncheck Delete Cropped Pixels (circle) and confirm crop on checkmark (arrow)

If you have unchecked Delete Cropped Pixels in the options bar you can select Move Tool at any time, click on image and move it around to change which pixels are visible and will be saved once you decide to save or export your image.
Move image after cropping with Delete Cropped Pixels unchecked
Move image after cropping with Delete Cropped Pixels unchecked

Conclusion
In order to have images with best possible quality you must know and some tips and tricks because you will deal often with images created and saved by others. That images are often already resampled and compressed, although Photoshop have the best tools available he cannot do things over today's technology. Resampling and compressing images multiple times will cause lost of quality, so try to skip interpolating pixels whenever it is appropriate and not necessary. I recommend you to read and What you should know before placing images in Photoshop and Illustrator with related topic.

Here is video The Newly Redesigned Crop Tool in Photoshop CS6 from series of videos The Complete Picture with Julieanne Kost available on Adobe TV along with other free useful videos and how-to's for Photoshop and other Adobe products.


Reference:
Photoshop Help / Adjusting crop, rotation, and canvas
Photoshop Help / Advanced cropping, resizing, resampling
Photoshop / Image size and resolution 

Product used in this tutorial: Adobe Photoshop CS6

Comments

  1. Oops! I see Bicubic AUTOMATIC mentioned in this post! It isn't real clear what it means, though. Is it only for pre-set sized cropping?

    I will check back! Thank you so much for helping with this!

    Su

    ReplyDelete
  2. Hi Su, Bicubic Automatic means that Photoshop will automatically detect and use method of interpolation which is best for you based on new versus old dimensions.

    ReplyDelete

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