Exercise 6 Basic Image Correction

	Imaging 1
f	Exercise 6 – Basic Image Corrections
Name	Paul Livingston
	§ This is a formative assessment instrument § 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 ? Command + R 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 ? 352 pix 2.98 cm (Hint: Use the info palette and the ‘Units & Rulers’ preference) b) What is the angle of the line ? –92.2 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) ? It spreads over the whole range of the histogram. b) Why does it look like this ? Loss of 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 ? Changing image size makes the image itself 1 cm larger while changing the canvas size give a 1 cm 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 a competent user, which I’m not, it aligns the horizontal and vertale stamp placement with the existing image. 21) Save the image as ‘MasterImage.tif’ 22) Close the document. 23) Quit Photoshop. 24) Delete the ‘Exercise 6’ folder. 25) Shutdown the computer.

Blog would not accept a Tif file.

Exercise 5 – File Types & Sizes

	Imaging 1
f	Exercise 5 – File Types & Sizes
Name	Paul Livingston
	§ This is a formative assessment instrument § You must be rated ‘Competent’ in this assessment item.
Learning Outcomes	Learning Outcome 6 - Identifying and define a range of file types and describe their uses, and compare and evaluate methods of uploading digital files using general operating systems and dedicated imaging software.
Tasks	1) Copy the file ‘Img 1 – Ex 5 – Image.tif’ from eLearn to ‘yourname-Ex5’. (Remember to delete this file when you have completed this exercise). 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
2. Height of the image in pixels	2000
3. Calculate the size of the image in Megapixels	5MP
4. What is the specified resolution of the image	300 ppi
5. Width of the image in cm	21.17
6. Height of the image in cm	16.93

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 MB
2) TIF file using LZW compression	10.4
3) Photoshop .psd file	15MB
4) Jpeg file – Quality level 12	4.2MB
5) Jpeg file – Quality level 10	1.9MB
6) Jpeg file – Quality level 5	680KB
7) Jpeg file – Quality level 1	401KB
8) GIF file – 256 colours – no dithering	2.9MB
9) GIF file – 256 colours – diffusion dither	3.5MB
10) GIF file – 16 colours – diffusion dither	1.4MB

Select ‘Image -> Mode -> Greyscale’ to convert the image to a grayscale image & save as

11) TIF file (no compression)

5.1MB

Select ‘Image -> Mode -> Bitmap’ to convert the image to a bitmap image & save as

12) TIF file (no compression)

741KB

3) Discuss the following with the class and post the answers on your blog :- a) Explain the difference in the sizes of the two tiff files in steps 1) and 2). LZW is a lossless compression. That is it compresses the size of the file without loss of data using a lookup algorithm. b) When saving a jpeg file what two things change when you select a different quality factor? Size of the file and quality of the image that limits the ability to enlarge. It also reduces the colour values as you select lower quality factors. c) What is ‘dithering’ and why is it used ? The positioning of different coloured pixels within an image that uses a 256-colour palette to simulate a colour that does not exist in the palette. A dithered image often looks 'noisy', or composed of scattered pixels. Google definition viewed 28 March 2011 <publications.europa.eu/vademecum/vademecum/9313fdfe-c49e-119e-45c6a6441e63e066_en.html> d) Explain the difference in size between the greyscale tiff file and the original tiff file. The greyscale is an 8 bit file while the original is a 24 bit file (8 bit per channel).

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.

Exercis 3 - Photoshop Interface

	Imaging 1
f	Exercise 3 – Photoshop Interface
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) Create a folder on the Desktop called ‘yourname-Ex 3’. 2) Copy the files for Exercise 3 from eLearn and place them in the new folder. (Remember to delete this folder from the desktop when you have completed this exercise). 3) Identify the following items on the diagram below :- Menu Bar Tool Bar Options Bar Button Bar Palettes / Panels Image Title Bar Status Bar 4) Start Photoshop CS5. Describe three ways of starting Photoshop :– i) Click PS icon on dock ii) Drag photo onto icon iii) Open via application file 5) Open ‘Photoshop->Preferences->General …’. Turn off the option ‘Zoom Resizes Window’. Click ‘OK’ to save the change. 6) Toggle the main tool bar between a single column of icons and a double column. 7) What are the shortcut keys for the following tools :- a) Hand (or Pan) tool H b) Move tool v c) Crop tool c d) Text (Typing) tool t e) Zoom tool z 8) Perform the following on the Palettes / Panels to the right of the screen :- a) Collapse the panels to icons with text (Click on the window bar) b) Resize to only display the icons. c) Expand to full panels d) Rearrange the blocks of panels by dragging them to a new location. e) Drag one panel onto a different group of panels by dragging its tab. f) Drag a group of panels off to make it independent of the rest. g) Drag a single panel off to make it independent of the rest. 9) Open the image file ‘Img 1 – Ex 3 - Image-1.jpg’ and do the following :- a) What is the colour mode of the image, and what is the bit depth of the image ? (Identify two locations where this information can be found). RGB 8bit image>mode & status bar Document Profile b) What is the zoom percentage that the image is displayed at ? 33.33 c) Change the zoom percentage to 28%. d) Click on the green button on the title bar. What happens ? Fill the frame e) Fit the image to the screen. What is the zoom percentage ? 36.61­­­ and what is the keyboard shortcut ? Quick fit button f) Zoom to 100%. What is the keyboard shortcut for this ? command Option 0 g) What does 100% zoom mean ? View at 100% magnification h) What do the ‘ + ‘ and ‘ - ‘ keys do ? Increase & decrease size i) Use the status bar information to answer the following (Click on the small triangle to change which information item is displayed) :- i) What is the image size in pixels and the image resolution in dpi ? 17.1x24.6 300 ppi ii) What is the document size in Mb ? 16.8M/16.5M What do the two sizes refer to ? Number on the left displays the uncompressed size of the image if it were to have all layers flattened. The number on the right displays the uncompressed size of the document including all layers and channels. j) Go to the ‘Window->Arrange’ menu to open a second window containing the same image :- i) Drag one document away from the tab. ii) Zoom both windows to 100% iii) Select the Hand tool and pan one of the images around. iv) Pan both windows simultaneously by holding down the shift key while you pan. v) Close one of the document windows. 10) Open the remaining three documents. a) Use the ‘Window->Arrange’ menu items to float the windows and consolidate them to the tabs. b) Use the button bar icon to try different window arrangements. 11) Press the ‘Tab’ key. What happens ? Press the “tab’ key again. Hides the toolbar and the panels and tab again to make visible. 12) Use the button bar icon to try different screen modes. 13) Close all documents. What is the keyboard shortcut to close a document window ? command w 14) Quit Photoshop. What is the keyboard shortcut ? command q 15) Delete the ‘yourname-Ex 3’ folder from the desktop. 16) Shutdown the computer.