How to Resize your Digital Images for RPS Digital Competitions
This is a brief guide to illustrate how to resize your digital images prior to submitting them for digital competitions. The guide describes the resizing techniques using Photoshop CS2. Other image editing programs, such as Adobe Elements, use slightly different menu items and dialogs, however, the exact same principles apply. Consult the On-line Help for your image editor to find the corresponding functions.
The Digital Projector
The first thing to keep in mind is that the digital projector always displays a fixed sized, horizontal image. That image is always 1024 pixels wide and 768 pixels high.
Most digital cameras produce an image much larger than the projector. For example, the Canon Digital Rebel produces images that are 3072 x 2040. This is much larger than the image size that the project can produce.
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As you can see, any part of the image that extends beyond the projector boundaries will be lost. Therefore, the goal is to shrink the image down so it no longer extends outside the projector boundaries. However, it’s important to also maintain the proportions between the width and the height of the image so it doesn’t get distorted as it is resized.
Resizing a Portrait Image
A portrait (or vertical) image is taller than it is wide. In this case we will resize the height of the image so it doesn’t exceed the height of the projector.
- Choose Image > Image Size … from the main menu to open the Image Size dialog.
- Make sure the Constrain Proportions and Resample Image checkboxes are checked.
- Set the Pixel Dimensions to pixels.
- Change the value of the Height field to 768.
- Finally, click OK to complete the resizing operation.
Notice that the Width field has been reduced to 510 pixels. The image width is now smaller than the width of the projector so the entire image will now fit within the boundaries of the projector.
Resizing a Landscape Image
A landscape image is wider than it is tall. This time we’ll start by reducing the width of the image to the width of the projector.
- Choose Image > Image Size … from the main menu to open the Image Size dialog.
- Make sure the Constrain Proportions and Resample Image checkboxes are checked.
- Set the Pixel Dimensions to pixels.
- Change the value of the Width field to 1024.
Again, notice that the height of the image is now 680 pixels. This is less than the height of the projector so the image will fit completely within the projector’s boundaries.
A Caveat with Landscape Images
Generally, when you have a tall (portrait) image, you reduce the height to match the projector. When you have a wide (landscape) image, you usually reduce the width to match the projector. However, you have to watch out for a special situation with landscape images. If the image is more square than the projector reducing the width may not be the correct solution.
Let’s see what happens with a landscape image that is 1342 x 1146.
In this case the image width now matches the width of the projector, but the height is still larger than the height of the projector. The top and bottom edges of the image will be cut off.
So what do you do?
When you run into this situation you need to click Cancel to start over. When you start over you treat this image as if it were a portrait image and reduce the height to 768 pixels.
Now you’ll see that the width is less than the width of the projector so this image will now fit on the screen as illustrated below.
Setting the Final File Size
The RPS Digital Competition rules require the overall file size to be no greater than 300KB. This has nothing to do with the height or width of the image. The final file size is how much space the file takes up on a disk. The amount of space the file takes up on disk is determined by the Quality setting you choose when saving the file.
- Open your image in Photoshop
- After you have set the height and width correctly, choose File > Save As… from the main menu.
- The Save As dialog will allow you to specify the file name for your finished image.
- When you click the Save button the JPEG Options dialog will appear
- Slide the Quality slider to the left until the file size is less than 300KB.
- Finally, click the OK button to save your file. It is now ready to submit for competition.
