Exercise 7 - Selections

	Imaging 1
f	Exercise 7 – Selections
Name PaulLivingston
	§ 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 ‘Selections.jpg’ from eLearn and place it on the desktop. (Remember to delete this file when you have completed this exercise). 2) Start Photoshop and open the document ‘Selections.jpg’ 3) Display the Histogram palette (‘Windows -> Histogram’) 4) Open the levels or curves palette (‘Image -> Adjustments ->Levels . . .’ and adjust the tonal range of the entire image, then close the palette. Observe the Histogram. 5) Select the rectangular Marquee tool – in the tool options bar set the feather value to 0, and the style to ‘Normal’. a) Select a small rectangular portion of the image and observe the histogram. b) Select a different area of the image and observe the histogram. c) Click within the selected area and drag it to a new location. d) What is the histogram showing you ? Shows the histogram only of the selected area rather than the entire image e) With the selection still active, open the levels or curves palette and make a change. What happens to the image ? Changes in levels or curves only apply to the selection f) Use the selection types buttons to add to and remove areas from the selection. g) Use the Shift and Alt keys to add to and remove areas from the selection. h) Select ‘Select -> Inverse’. What happens to the selection ? Marching ants appear around the exterior of the image What is the shortcut key for this ? Shift Cmd i) Select ‘Select -> Deselect’ or click once in the image to discard the selection. What is the shortcut key for this ? Cmd D j) Use the History palette (‘Windows -> History’) to undo all the changes you have made. k) Set the Rectangular Marquee style in the options bar to ‘Fixed Ratio’, enter a value for width and height (eg 2 and 3), then select an area of the image. What do you observe ? The size of the marquee stays in a the selected ratio regardless of how large or small the selection. l) Set the style to ‘Fixed Size’, enter a value for width and height (eg 200 and 100), then select an area of the image. NB You only need to click once – you don’t need to click and drag. m) Set the ‘Feather’ value to 25, select an area of the image and make a tonal or colour change to the image. What do you observe ? A new layer made and when you do the tonal change the edges of the change are graduated so they blend with the surrounding area. n) Press +D or click once in the image to discard the selection. o) Use the History palette to undo all the changes you have made. 6) Select the circular Marquee tool – set the feather value to 0, and the style to ‘Normal’. a) Select a small portion of the image. b) Press +D or click once in the image to discard the selection. c) Click and drag to start selecting a portion of the image. Before releasing the mouse button press and hold the shift key. What happens ? Changes the ellipse to a perfect circle d) Press +D or click once in the image to discard the selection. e) Click and drag to start selecting a portion of the image. Before releasing the mouse button press and hold the Alt/Option key. What happens ? The size of the selection is doubled f) Press and hold the shift key while you select another portion of the image. What happens ? The size of the selection stops and it moves location with the mouse g) Press and hold the alt / option key and select a portion of the image that overlaps the existing selection. What happens ? It removes area from the selection. 7) Select the Lassoo tool . a) Select a small portion of the image. b) Add and subtract areas to / from the selection and use the feather option. c) Discard the selection 8) Select the Polygonal Lassoo tool . a) Select part of the image by clicking a start point and adding nodes until you click on the start point again to finalise the selection. b) Start a new selection and use the Esc key to abort the selection before you finalise it. c) Start a new selection, add some nodes and then use the Delete / Backspace key to backstep through the nodes you have added. d) Set the feather value to 2. e) Select the two areas of the timber wall. f) Use the Hue control to change the colour of the wall. g) Go to ‘Select->Save Selection . . .’ and save the selection as Walls. h) Discard the selection. 9) Select the Magnetic Lassoo tool . a) Select the grey metal roof by clicking a start point and tracing along the edge to add nodes until you return to the start point to finalise the selection. Use the Esc key to abort, and the Delete key to remove unwanted nodes if you need to. Click on any point to force a node to be created. You may need to use the other selection tools to tidy up edges etc to make an accurate selection. b) Save the selection as Roof. 10) Select the Magic Wand tool . a) Set the tolerance to 32 b) Click in the sky to select part of the sky. c) Hold down the shift key and click to add all the sky and clouds into the selection. Use +Z or the History palette to undo the last addition if required. d) Save the selection as Sky 11) Use whichever tools you want to make and save a selection for the bricks. 12) Select ‘Select->Load Selection . . .’ and set Operation to ‘New Selection’ and reload the selection of the sky. a) Use ‘Select->Inverse’ to invert the selection ie the entire building will be selected instead of the sky. b) Save this selection as ‘Building’ 13) Choose ‘Select->Color Range . . .’ a) Click on the blue part of the sky and use the Fuzziness slider to select all the blue sky. b) Use the Burn tool to darken just the lower part of the blue sky without affecting the building or the white clouds. c) You can use +H to hide the selection outline while you do this. Use +H to reveal the selection outline when you have finished. 14) Close the document. 15) Quit Photoshop. 16) Delete ‘Selections.jpg’ from the desktop. 17) Shutdown the computer.

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).