ACTIVITY: Image resolution
For this activity you will need image editing software, such as Photoshop
(for more information, see Image editing programs).
If you are not sure how to download images from the web, go to Downloading
images.
-
Download this image to disk.
-
Open the image in Photoshop (File:Open) and view the image at 100% (zoom factor
is displayed in top of image frame). Go to Image>Image size and note pixel
dimensions, data size, document size and resolution of the image.
-
Uncheck the 'resample image' checkbox and change the image resolution to 150ppi
- note the document size (print measurement), pixel dimensions and data size.
Then change the resolution to 300ppi - note the document size, pixel dimensions
and data size. The image is not resampled, so the data size does not change. Do
the pixel dimensions change? Does the document size change?
Click OK. Does the image appear differently on screen?
-
Go Back to Image>image size, and check the 'resample image' checkbox. The
pixel dimensions are now editable. Change the image resolution to 50ppi, then
to 150ppi. Do the pixel dimensions change? Does the document size change?
Click OK. Does the image appear differently on screen?
|
Image 1 - JPEG
|
|