(f) Exercise 5 - File Types and Sizes

(f) Exercise 5 - File Types and Sizes

This is a formative assessment instrument
You must be rated ‘Competent’ in this assessment item.

Learning Outcomes Learning Outcome 1 - Identify and define a range of file types and describe their uses.

Tasks
1) Copy the ‘Lesson 6’ folder from the server.
2) Open the file ‘Img 1 – Ex 5 – Image.tif’ in Photoshop and do the following :-
Select ‘Image -> Image Size …’ :-

1. Width of the image in pixels - 2500 Pixels
2. Height of the image in pixels - 2000 Pixels
3. Calculate the size of the image in Megapixels - 5 Megapixels
4. What is the specified resolution of the image - 30 Pixels/Inch
5. Width of the image in cm - 21.17 cm
6. Height of the image in cm - 16.93 cm

Select ‘File -> Save As…’ and save the image in the following formats. Name the files to clearly identify them.
After each save close the image and reopen to save to the next format. Use the Finder/File Browser to record the sizes of the files created.

1) The original .tif file - 15.2 MB
2) TIF file using LZW compression - 10.6 MB
3) Photoshop .psd file - 15 MB
4) Jpeg file – Quality level 12 - 4.2 MB
5) Jpeg file – Quality level 10 - 1.9 MB
6) Jpeg file – Quality level 5 - 721 KB
7) Jpeg file – Quality level 1 - 442 KB
8) GIF file – 256 colours – no dithering - 2.9 MB
9) GIF file – 256 colours – diffusion dither - 3.5 MB
10) GIF file – 16 colours – diffusion dither - 1.5 MB

Select ‘Image -> Mode -> Greyscale’ to convert the image to a grayscale image & save as
11) TIF file (no compression) - 5.1 MB

Select ‘Image -> Mode -> Bitmap’ to convert the image to a bitmap image & save as
12) TIF file (no compression) - 754 KB


Just to post two example images from the Exercise

Here is the original image



And this is the image after it was converted to Jpeg with a quality level of 1.




It is quite hard to see the difference between the two images from the smaller uploaded files but there is a definite size difference as shown in the table.