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Year 10 Photography

File Size Exercise

Task 2

1. Open the image ‘File Size Exercise’.

2. Go to the Image Size menu in Photoshop and note down the size of your original image in pixels onto scrap paper.

3. Go to ‘Save As’ and resave the image to your drive as a Photoshop (psd) image. This is the standard file format that must be used whilst working in Photoshop. Images are uncompressed and are much bigger in file size than jpg images. NOTE that the pixel size of the image will be the same as your original jpg image.

Saving Images as jpg’s

JPG images are compressed images similar to MP3 (music) and MP4 (video) files. When saving images as jpg’s you will be given the choice of the amount of compression that you want. The more compression, the smaller the file size but the trade of will be a decrease in image quality. The following exercises will demonstrate to you the amount of compression that can be achieved for various image sizes (measured in pixels).

Preparing Images for Emails

Reload you original jpg image ‘File Size Exercise’.

Go to the ‘Image Size’ menu and change the pixels to give a maximum size on one axis of 1000 pixels (Less pixels could be used depending on how high a quality image you want to email). Note down the image size in pixels as this will be needed.

Go to ‘Save As’ and change the file name to ‘file_1000_high’ (Make sure you have the jpg option selected). When you select save a menu will appear asking you what quality image you require. Select highest and save.

Go to ’Save As’ again and resave with a new file name of ‘file 1000 medium’ this time select medium quality from the menu (about 5 on the scale). Selecting medium will increase the level of jpg compression and reduce the file size of your image at the expense of some loss of image quality.

Preparing Images for Face Book or Word Usage.

a) Reload you original jpg image.

b) Go to the ‘Image Size’ menu and change the pixels to give a maximum size of 400 pixels. Note down the pixel sizes.

c) Go to ‘Save As’ and change the file name to ‘file_400_high’. When you select save a menu will appear asking you what quality image you require. Select highest and save.

d) Go to ’Save As’ again and resave with a new file name of ‘file 400 medium’ this time select medium quality from the menu (about 5 on the scale).

You can now open ‘My Computer’ and check to see that you have the following images:

File_large

Photoshop

File_1000_high

File_1000_medium

File_400_high

File_400_high

File_400_medium

Below is a table showing the quite dramatic results from a typical 10 Megapixel Image

|Image in pixels |File Type |jpg compression |File size |

|3872 x 2592 |Psd (photoshop) |none |29,229 KB |

|3872 x 2592 |jpg |High quality |5,553 KB |

|1000 x 669 |jpg |High Quality |658 Kb |

|1000 x 669 |jpg |Medium Quality |110 KB |

|400 x 268 |jpg |High Quality |141 KB |

|400 x 268 |jpg |Medium Quality |48 KB |

Complete the table provided for the images that you have produced.

Student Task on File Sizes

a) Check that all the required images are in your personal folder and correctly named.

b) Note down the names and the file sizes produced in Kb (you should already have the image sizes in pixels).

c) Open a new Word document and add the title File Size Exercise by ‘your name’

d) Insert a copy of the smallest of your images (400 pixels) to show the image you have been working with.

|Image in pixels |File Type |jpg compression |File size |

| |Psd (photoshop) |none | |

| |jpg |High quality | |

| |jpg |High Quality | |

| |jpg |Medium Quality | |

| |jpg |High Quality | |

| |jpg |Medium Quality | |

e) Copy the table above into your document and then add the figures you have collected, as per the previous page.

f) Print a copy of your work and place in your folder. Save your document to the student folder shown to you by your teacher with the file name:

‘your surname_first name_file size’

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