Height: 21.25


Resolution: 24Cj f pixels/inch ) t j

._Scaie Styles

/ Constrain Proportions

Resample Image: Bicubic

FIGURE 78 Using the Image Size box to redistribute pixels.

Figure 78(b) is the Image Size box that would result if I later changed my mind and decided that I wanted to make a larger print without compromising the quality of my photograph.

Notice that I've changed the resolution to 240, the minimum for high-quality ink jet prints but the file size is the same, 99.8 megabytes. The difference is that image pixels in the larger print will be a little bigger.

The "Resample Image" box tells Photoshop to mathematically create new pixels to replace the original ones in your image. Because that box is not checked, the same amount of information is simply distributed in different ways. It would be an example of destructive interpolation if I had upscaled the image's file size.

• File Size Calculator. It's sometimes necessary, or just interesting, to know what total file size will result from a given combination of image settings. Adobe Photoshop has a feature that essentially functions as a file size calculator that instantly accounts for all of the variables we've been discussing.

In Photoshop if you select File > New the following box will appear.

FIGURE 79 Photoshop New Box as a file size calculator.

Notice that all of the image quality settings are present.

1. These are the dimensions of the largest print I plan to make from this file. The drop down menu also gives me the option of displaying this as the equivalent number of pixels.

2. 300 dpi is the standard resolution for high-quality ink jet prints. 240 and 360 are other possible choices.

3. This setting shows that I will have three color channels in this image.

4. 16 bits per channels will allow for editing without degrading the image. When this file is ready to print I would change the mode of this image to 8 bits per channel, which would reduce the file size by 50%. There's no quality advantage to sending more than 8 bit files to the printer. 5. This is the total file size that results from these settings.

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