Exercise 4 - Bit Depth and Colour Modes

	Imaging 1
f	Exercise 4 – Bit Depth and Colour Modes
Name	Paul Livingston
	§ This is a formative assessment instrument § You must be rated ‘Competent’ in this assessment item.
Learning Outcomes	Imaging 1 – All Learning Outcomes.
Tasks	1) Download the file ‘Img 1 – Exercise 4’ from eLearn and place it on the desktop. (Remember to delete this file from the desktop when you have completed this exercise). 2) How big is an A4 page in cm ? 21 x 29.7 cm 3) Open the file ‘Img 1 – Ex 4 - Granger-Rainbow.jpg’ in Photoshop :- 4) Select ‘Image -> Image Size …’ and ‘Image -> Mode’ and answer the following questions :– Image size in cm 29.63 x 20.32 Pixel Dimension (W x H) 3500x2400 Image size in megapixels 8.4 Resolution of the image (ppi) 300 Image size in megabytes 24 Colour Mode RGB Bit depth 8 Hint: Use the Status line to display the image size – use the number on the left. 5) Use the ‘Image -> Mode’ menu to select the following modes / bit depths and fill in the table for each case listed. (Note: Use ‘Undo’ or the History list after each case to return to the original image state) :- Colour Mode Bit Depth per channel Total Bit depth No. of available colours Image Size (Mb) RGB 8 24 16,777,216 25.2 RGB 16 48 2.8x 10 to14th 48.1 CMYK 8 32 4.2 billion 33.6 Greyscale 8 8 256 16.8 Bitmap # 1 1 2 8 Indexed Colour – 256 colours N/A N/A 256 8

# You can only convert to Bitmap from a geyscale image.