Lesson 02 Colour

Imaging 2

Exercise 3 – Colour Theory 1
Names

 This is a formative assessment instrument
 You must be rated ‘Competent’ in this assessment item.
Tasks 1. Start Photoshop and create a new document with the following properties :-
• Name : ‘Ex 3 – Primary Colours’
• Size : A4 @ 300dpi
• Colour Mode : RGB / 8 bpc
• Background Colour : White
2. What is the keyboard shortcut for creating a new Document ? ctrl N
3. What is the size of the image in :-
 Megapixels - 8.7 Megabytes 24.9mb
4. Set the foreground colour to Red (ie R 255, G 0, B 0).
5. Select the Ellipse Tool (not the Marquee tool). What is the keyboard shortcut :-
6. Draw a circle with the Ellipse tool approximately 6cm in diameter (about 1/3rd of the page width) – display the rulers and use Preferences to set the units to cm .
• Which key forces the ellipse to be a circle ? Shift

7. Change the layer name to ‘Red Circle’.
8. Duplicate the layer and
• change the colour to green and
• change the name to ‘Green Circle’.
Note: To change the colour click on the colour button on the option bar immediately after duplicating the layer, or double click on the layer in the Layers palette.
9. Duplicate this layer and
• change the colour to blue and
• change the name to ‘Blue Circle’.
10. Select the Move tool. What is the keyboard shortcut ? V
11. Turn on the ‘Auto-select’ option.
12. Spread the three circles across the top of the page with a small space above them (they may overlap a bit – that’s OK).

13. Fit the image to the screen (ie so the whole page is visible).
• What is the keyboard shortcut for this ? Ctrl + 0
14. Go to Full Screen Mode – ‘View -> Screen Mode ->Full Screen Mode’.
• What is the keyboard shortcut ? Tab
15. Stare at the centre of the middle circle for 20 seconds, then look at the white area below. You will see an after image.
• What colour are the after images for each circle ?
Circle After Image Colour
Red Cyan
Green Magenta
Blue Yellow

16. Select all three layers in the layers palette.
17. Group the three layers together by selecting ‘Layer -> Group’.
• What is the keyboard shortcut ? Ctrl + G
18. Select the group in the layers palette containing the three circles.
19. Change the ‘Blending Mode’ for the group from ‘Pass Through’ to ‘Difference’. (We will be looking at Blending Modes later, so don’t worry if you don’t understand them now).
20. Stare at the centre of the middle circle for 20 seconds, then look at the white area below. You will see an after image.
• What colour are the after images for each circle ?
Circle After Image Colour
Cyan Red
Magenta Green
Yellow Blue

21. Save the document as ‘Ex 3 – Colour Theory.psd’
22. What is the size of the .psd file on disk? 1.12mb How does this compare to the image size you recorded in step 3 above. Smaller file size





Imaging 2

Exercise 4 – Colour Theory 2
Names

 This is a formative assessment instrument
 You must be rated ‘Competent’ in this assessment item.
Tasks 1. Start Photoshop and open the document you created in Exercise 3.
• What is the keyboard shortcut for opening an existing Document ? Ctrl + O
2. Change the Blending Mode of the layer Group to ‘Pass Through’.
3. Make the background layer the working layer by selecting it in the Layers palette.
4. Use the Rectangular Marquee tool to select the top half of the image.
5. Use the Paint bucket tool to fill this area with Black.
• What is the keyboard shortcut for this tool ? G
6. Change the Blending Mode of the ‘Red Circle’ layer to ‘Lighten’.
7. Do the same for the Blue and Green Circle layers.
8. Select the Move tool.
• What is the keyboard shortcut for this tool ? V
9. Turn on the ‘Auto-select’ option and set it to ‘Layer’ (Not ‘Group’).
10. Drag the three circles so they all overlap each other.

11. This simulates the Additive/RGB Colour System.
12. Rename the group of circle layers to indicate this.
13. Add a text layer (using white text) saying ‘ Colour System’.
14. Select the group of circles in the layers palette.
15. Duplicate the group using ‘Layer -> Duplicate Group …’.
16. Use the Move tool with ‘Auto-Select’ set to ‘Group’ to drag the new group to the bottom half of the page.
17. Change the Blending Mode of the this group to ‘Difference’.
18. This simulates the Subtractive/CMYK Colour System.
19. Add a text layer saying ‘ Colour System’.
20. Save the document as ‘Ex 4 – Primary_Colours.psd’