When opening the first image of a new project, the canvas size is automatically set to the Image size. The second and successive images will not change the canvas size, they will be put on the canvas as determined by the first image. This is not necessarily what you may want. You can right-click the Object to change the following size properties:

  • Set the canvas size to the image size. Setting the canvas to the image size assures that it fits perfectly on the canvas, with no background showing underneath, and no part of the image hidden from view.
  • Fit the image to the canvas.  Fitting an image to the canvas assures that the longer edge of the image touches the border of the canvas. The whole image is visible in the maximum possible size, but on the shorter edges the canvas will be visible.
  • Cover the canvas with the image.  Covering the canvas with the image assures that even the shorter edge of the image is big enough to hide the canvas. Parts of the image will be outside of the canvas (and will appear hidden underneath it), but the whole canvas will be covered by the image. This is a very good setting for textures.

You can click the Properties to resize the Object or to adjust its brightness, gamma, and/or contrast.

To modify the Object’s size, click the “Properties + Preview” pane and drag the Size slider to the desired value. You can also resize the image from the Objects/Resize current object menu. This works the same way as in any other graphic editor software.

 

The Resize Current Object dialog box

The size of an image when you view it on the screen is different from the size of an image when you print it. It is fundamental you understand these differences, so that you can develop a better understanding of which settings to change when you resize your image.

Load an image and from the Objects menu open the Resize Current Object dialog box.

The dialog box with the default values of the image appears. Note that these values are the same present in the Image Properties in the Properties+Preview pane when selecting the Object.

When you use the Object resize dialog box to resize your images, three aspects of your image can change:

  1. 1. the pixel dimensions, which is the width and height of the image in pixels - in the Pixel Dimension section
  2. 2. the physical size of the image when printed, in width and height - in the Document Size section
  3. 3. the resolution of the image when printed (the amount of data in the image for printing), which is the number of pixels per inch or per centimeter - in the Document Size section. The resolution is the amount of detail in the image.

Note: The amount of data in an image is controlled by the pixel dimensions, and the resolution and the physical size are used only for printing.


The Object resize dialog box allows you to decide wether to resize with resampling (resample turned on) or maintaining the same amount of data in the image (resample turned off). Resample is on by default. It is important to understand that resampling changes the total number of pixels in the image, which are displayed as Width and Height in pixels in the Pixel dimensions section of the dialog box. When you increase the number of pixels in this section (upsampling), the application adds data to the image, and when you decrease the number of pixels (downsampling), the application removes data. Whenever data is removed from or added to the image, the image quality degrades to some extent.

 

With Resampling:

When you check, or turn on, Resample, you can change any or all of the three values in the Image Size dialog box: pixel dimensions, physical size, or resolution. If you change one value, then you will effect the others; the pixel dimensions are always affected.

  • If you change the Pixel dimensions, then you will affect the physical size, but not the resolution.

  • If you change the Resolution, then you will affect the pixel dimensions, but not the physical size. 
  • If you change the Document (physical) size, then you will change the pixel dimensions, but not the resolution.

Without Resampling:

When you resize an image without resampling it, you change the physical size of the image without changing the pixel dimensions (amount of data) in the image. When you uncheck Resample, the Pixel dimension fields are not available, and the only two values you can change are the Document size or the Resolution (DPI). As the Pixel dimensions do not change when resizing without resampling, PostworkShop compensates the value you are modifing by increasing/decreasing the other value: set manuall the Width and Height of the Image and PostworkShop will automatically calculate the new Resolution, and viceversa.

If you double the size of an image, the resolution decreases by half, because the pixels need to be twice as far apart to fit the physical size.

When the pixel dimensions are constant and you decrease the physical size of an image, the resolution increases correspondingly. If you decrease the physical size of an image by half, the resolution doubles, because twice as many pixels can fit into the same space.

The image properties will be updated to the new Physical dimensions and Resolution we previously set: