Page 17 - CC 2019 WD Look Inside

5. Choose Image>Image Size.
The actual number of
The Image Size dialog box shows the pixels in the image is
number of pixels in the image, as well the most important
as the image dimensions and current information.
resolution. You can change any value
in this dialog box, but you should
understand what those changes mean
before you do so.

As you can see, this image is currently Use this widget to Click and drag in the
37.5 inches wide and 50 inches high, change the preview window to
but it was photographed at 72 pixels/ preview percentage. show a different area.
inch. For most commercial printing,
you need at least 300 ppi. You can use the principle of effective resolution to change
the file to a high enough resolution for printing. Note:
Press Command-
6. Check the Resample option at the bottom of the dialog box (if necessary). Option-I/Control-Alt-I

The options in this dialog box remember the last-used choices. The Resample option to open the Image Size
might already be checked in your dialog box. dialog box.

Resampling means maintaining the existing resolution in the new image dimensions.
In other words, you are either adding or deleting pixels to the existing image. When
this option is turned on, you can change the dimensions of an image without affecting
the resolution, or you can change the resolution of an image (useful for removing
excess resolution or downsampling) without affecting the image size.

7. Change the Resolution field to 300 pixels/inch.
When you change the resolution with
resampling turned on, you do not
change the file’s physical size. To When Resample is
achieve 300 ppi resolution at the new checked, changing the
size, Photoshop needs to add a huge Resolution value adds
number of pixels to the image. You or removes pixels.
can see at the top of the dialog box
that this change would increase the
total number of pixels from 2700 1
3600 to 11250 1 15000.

You can also see that changing the resolution of an image without affecting its physical
dimensions would have a significant impact on the file size. Changing the resolution
to 300 ppi at the current size would increase the file size to nearly 483 megabytes.
Higher resolution means larger file sizes, which translates to longer processing time
for printing, or longer download time over the Internet. When you scale an image
to a smaller size, simply resizing can produce files with far greater effective resolution
than you need. Resampling allows you to reduce physical size without increasing the
resolution, resulting in a smaller file size.

The caveat is that once you delete pixels, they are gone. If you later try to re-enlarge
the smaller image, you will not achieve the same quality as the original file before
it was reduced. You should save reduced images as copies instead of overwriting the
originals.

Project 1: Composite Movie Ad 29