File Format Assignment

This assignment is intended to get you familiar with scanning and with file formats.

1) Scan both of your images into a resolution around 500x500. Go no larger than 800x800 and no smaller than 300x300. Scan them at 8 bits/pixel, greyscale (might be called "black and white photo" on the scanner). If you are scanning a typical 4x6 photo, this would mean scanning at about 100 dpi.

2) You are going to save your photograph image in 5 different file formats. In Photoshop, this can be done with File->Save As, where you will be given a choice of different formats to use. The formats you need to save as are TIFF (with compression), GIF (normal), JPEG (with maximum quality), JPEG (with minimum quality), and the native file format of your image editing system ("Photoshop" if you’re using Photoshop).

Save the files with the same base name, i.e., "assignment1" but use different extensions. Typical extensions for the formats given above are:
format: extension example
TIFF .tif assignment1.tif
GIF .gif assignment1.gif
JPEG .jpg assignment1.jpg
Photoshop .psd assignment1.psd

Since you’re saving two versions of JPEG images, you will want to do something to differentiate them on disk (for example, "assignment1.min.jpg" and "assignment1.max.jpg").

3) Look at the sizes of the 5 files you have on disk. Hand in a sheet listing the files in order of decreasing size (biggest to smallest). Be sure to include their sizes (in bytes, kb, or Mb). Also, please include the spatial resolution of your image (i.e., 576x339). How many times bigger is the "maximum quality" JPEG than the "minimum quality" one?

4) Load each of the images separately and see if you can identify any visual difference between them. Can you? Which formats look different, and in what ways do they look different? Note these differences on the sheet.