Imaging 1
Exercise 6 – Basic Image Corrections
Name
ß This is a formative assessment instrument
ß You must be rated ‘Competent’ in this assessment item.
Learning Outcomes Learning Outcome 8 - Identify and explain a range of digital imaging concepts such as colour mode, colour space and bit depth as well as demonstrate typical fundamental digital image enhancement techniques, and identify digital image workflow patterns and create a simple file management methodology that conforms to established industry norms.
Tasks 1) Copy the file ‘BadImage.jpg’ from eLearn and place it in a folder ‘Exercise 6’ on the desktop. (Remember to delete this folder when you have completed this exercise).
2) Start Photoshop and open the document ‘BadImage.jpg’
3) Rotate the image 90 degrees to orientate it correctly.
4) Display the Rulers. What is the keyboard shortcut ? (i)
5) Use ‘Photoshop->Preferences->Units and Rulers…’ to swap between cm and pixels for the ruler dimensions.
6) Display the Grid. What is the keyboard shortcut ? command (‘)
7) Use ‘Photoshop->Preferences->Guides, Grids, Slices and Count …’ to change the grid spacings.
8) Use the Ruler tool to draw a line down the centre of the façade following the joins in the bricks.
Record the following :-
a) How long is the line in pixels and in cm ? 558.52p 4.73cm
(Hint: Use the info palette and the ‘Units & Rulers’ preference)
b) What is the angle of the line ? –92.5
9) Rotate the image so the image is straight using ‘Image->Rotate->Arbitrary…’
10) Use the Crop tool to crop out any background pixels added around the outside of the image - you will lose some of the image to do this.
Note: You can use the arrow keys to nudge the selected area by one pixel at a time. Shift + Arrow key nudges by 10 pixels.
11) Open the Curves palette and adjust so the image has a full tonal range and good overall brightness (Gamma correction).
a) What has happened to the histogram (what does it look like) ?
The histogram spreads across the whole graph
b) Why does it look like this ?
Increasing contrast leads to missing tonal (brightness) values
12) Set the background colour to black.
13) Increase both the width and height of the image by 1cm using ‘Image->Image Size …’.
14) Undo the change in size.
15) Increase both the width and height of the image by 1cm using ‘Image->Canvas Size …’.
16) What is the difference between changing the image size vs. changing the canvas size ?
Increasing the image size increases the image where as increasing the canvas size puts a border around the image
17) Select the Clone stamp tool and set the following parameters :-
a) Turn OFF the ‘Align’ option,
b) set the brush size to approx. 8 pixels, and
c) ‘Alt + click’ in the sky to set the point to start copying from.
18) Use it to remove the pole in the sky to the left of the tower.
19) Use the Clone stamp tool to remove a window from the façade of the building after setting the following :-
a) Turn ON the ‘Align’ option,
b) set a soft brush with a diameter of 20pixels, and
c) ‘Alt + click’ in the brickwork to set the point to start copying from.
20) How does the behaviour of the Clone Stamp change when the ‘Align’ option is turned off compared to when it is turned on ?
With the alignment on it helps you align straight lines
21) Save the image as ‘MasterImage.tif’
22) Close the document.
23) Quit Photoshop.
24) Delete the ‘Exercise 6’ folder.
25) Shutdown the computer.
Exercise 6 – Basic Image Corrections
Name
ß This is a formative assessment instrument
ß You must be rated ‘Competent’ in this assessment item.
Learning Outcomes Learning Outcome 8 - Identify and explain a range of digital imaging concepts such as colour mode, colour space and bit depth as well as demonstrate typical fundamental digital image enhancement techniques, and identify digital image workflow patterns and create a simple file management methodology that conforms to established industry norms.
Tasks 1) Copy the file ‘BadImage.jpg’ from eLearn and place it in a folder ‘Exercise 6’ on the desktop. (Remember to delete this folder when you have completed this exercise).
2) Start Photoshop and open the document ‘BadImage.jpg’
3) Rotate the image 90 degrees to orientate it correctly.
4) Display the Rulers. What is the keyboard shortcut ? (i)
5) Use ‘Photoshop->Preferences->Units and Rulers…’ to swap between cm and pixels for the ruler dimensions.
6) Display the Grid. What is the keyboard shortcut ? command (‘)
7) Use ‘Photoshop->Preferences->Guides, Grids, Slices and Count …’ to change the grid spacings.
8) Use the Ruler tool to draw a line down the centre of the façade following the joins in the bricks.
Record the following :-
a) How long is the line in pixels and in cm ? 558.52p 4.73cm
(Hint: Use the info palette and the ‘Units & Rulers’ preference)
b) What is the angle of the line ? –92.5
9) Rotate the image so the image is straight using ‘Image->Rotate->Arbitrary…’
10) Use the Crop tool to crop out any background pixels added around the outside of the image - you will lose some of the image to do this.
Note: You can use the arrow keys to nudge the selected area by one pixel at a time. Shift + Arrow key nudges by 10 pixels.
11) Open the Curves palette and adjust so the image has a full tonal range and good overall brightness (Gamma correction).
a) What has happened to the histogram (what does it look like) ?
The histogram spreads across the whole graph
b) Why does it look like this ?
Increasing contrast leads to missing tonal (brightness) values
12) Set the background colour to black.
13) Increase both the width and height of the image by 1cm using ‘Image->Image Size …’.
14) Undo the change in size.
15) Increase both the width and height of the image by 1cm using ‘Image->Canvas Size …’.
16) What is the difference between changing the image size vs. changing the canvas size ?
Increasing the image size increases the image where as increasing the canvas size puts a border around the image
17) Select the Clone stamp tool and set the following parameters :-
a) Turn OFF the ‘Align’ option,
b) set the brush size to approx. 8 pixels, and
c) ‘Alt + click’ in the sky to set the point to start copying from.
18) Use it to remove the pole in the sky to the left of the tower.
19) Use the Clone stamp tool to remove a window from the façade of the building after setting the following :-
a) Turn ON the ‘Align’ option,
b) set a soft brush with a diameter of 20pixels, and
c) ‘Alt + click’ in the brickwork to set the point to start copying from.
20) How does the behaviour of the Clone Stamp change when the ‘Align’ option is turned off compared to when it is turned on ?
With the alignment on it helps you align straight lines
21) Save the image as ‘MasterImage.tif’
22) Close the document.
23) Quit Photoshop.
24) Delete the ‘Exercise 6’ folder.
25) Shutdown the computer.
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