Visualizing Microbial Seascapes - Intro to Photoshop

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Scanning

  • See step by step instructions: Scanning from a Macintosh
  • Recommended scanning resolution for Zoetrope strips to Quicktime = 150dpi, for print = 300-600 dpi

Photoshop interface and navigating an image

  1. Opening a file File > Open and navigate to your file. Never open a file over the network (if your file is on Orca, first copy it to your local hard drive).
  2. Intro to basics Photoshop interface elements
  3. navigating an image
    • Zoom: Cmd +/-
    • Hand tool: Space Bar (used to move around an image)

Image size and resolution

  1. What is a pixel? Zoom all the way in on your image.
  2. What are the dimensions of your image?
    • Go to Image > image Size to see the overall size in pixels of your image
    • Resizing photos for various usages including: Web, email attachment, and print
  3. What is the resolution or pixel density of your image? Why does it matter? See more in discussion depth on resolution.
  4. Cropping - using the crop tool to remove portions of the image outside of the crop selection
    • You can set the image size to crop to in the properties bar i.e. 400 px (remember the px)

Saving your work

File > Save as. Choose Photoshop as the file format. This will create a uncompressed Photoshop native image file format (.psd). It's a good idea to keep an uncompressed copy of your images.

Working with Layers

  • Background layer is locked, you may need to copy it first before making adjustments
  • Copying between layers and duplicating layers
  • Layer visibility
  • Adjustment layers - try adding a Levels adjustment to improve the contrast of your scanned image

Working with selections

Animate your Zoetrope Strips into an animated GIF

Prep Your Image Sequence

  1. Scan the zoetrope strip. If you are working from a 3” x 36” 12 frame strip, you’ll need to make 4 scans to capture the entire strip. I recommend scanning at 150 dpi.
  2. Save each scan in a folder, numbered in the correct order, 1-4.
  3. In Photoshop, open the four images. Window > Arrange > 4 UP is a good view for this.
  4. If you need to make image adjustments, do that at this point.
    • Try adding adjustment layers, start with levels and set black and white points.
    • In 4-up view you can drag an adjustment layer to copy across documents.
    • Try the Spot Healing tool to fix stray marks
    • Once you've got your adjustment layers all dialed in Flatten the image by going Layer > Flatten Image
  5. Select the crop tool and straighten out and crop each of the four strip sections so they are the same height.
    • From the crop tool settings choose Original Ratio and enter in a fixed value for the height that can be used across all images.
    • Apply the Crop (Enter key) and move onto the next image, the crop settings will persist and can be reapplied

Break up the sequence into individual documents

  1. Select the marquee tool and set it for fixed aspect ratio, 450 x 450 pixels.
    • Place the marquee over the first frame, line up the bottom left corner of the marquee with the bottom left corner of the frame. Copy it and paste it into a new photoshop document. #*Save the new document to a new folder, label the document “[title]001”.
  2. Repeat this action for all the frames in sequence, saving and labeling each new frame so you end up with images numbered from 001 to 012 in the new folder.
  3. Close all the images.
Open an image sequence

Open an image sequence

  1. Go File > Open and select the first image in your sequence
  2. Check the Image Sequence box and click Open
  3. Set your frame rate 10 or 12 fps should suffice
  4. Open the animation timeline in Window > Timeline
  5. From the timeline "hamburger" button choose Set Timeline Frame Rate to adjust frame rate if needed

Output an animated GIF

  1. In Photoshop CS 6 go File > Save for Web and Devices
    • In Photoshop CC 2015 go File > Export > Save for Web (Legacy) ...
Set your looping options
  1. Choose a GIF flavor from the Preset drop down menu
    • note what happens to the file size and color table as you choose different GIF compression settings
  2. You should now be able to preview the animation in the lower right
  3. Set your Loop options - once or forever
  4. Click Save and name your animated gif file
  5. Open the animated GIF with a browser to view and test see how it turned out
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