BIO 498: Additional Photoshop Techniques Image Manipulation

Overview  A note  Image Rotation  Zoom  Light Adjustment  Levels  Shadows/highlights  Brightness/contrast  Sharpening  Removing background blemishes  More Analysis techniques

A Note  An important thing to keep in mind is that when you image specimens for analysis/identification and NOT for artistic purposes; the less you alter the image, the more reliable the information you gain from it.  Editing in Photoshop should always be minimal, without changing the information in the image.

Image Rotation: Upside-down Image  If specimen is upside- down, go to Image > Image Rotation > Flip Canvas Vertical

Image Rotation: Arbitrary  Go to Image Rotation > Arbitrary…  Arbitrary window will open  Enter the amount of degrees you wish the image to be rotated, and specify Clockwise (CW) or Counterclockwise (CCW)

Image Rotation: Arbitrary  Canvas will rotate degree specified.  Note: It is unwise to crop the image before an arbitrary rotation. It’s suggested you crop AFTER rotating.

Zoom  To Zoom In: Select Magnify tool on side toolbar (Magnifying glass) OR press “Ctrl +/=” on keyboard  To Zoom Out: press “Ctrl –”

Lighting Adjustment When to Use When NOT to Use  If image taken was over- or underexposed  If there is an aspect of the specimen you want to make more noticeable (ie: stomata on a leaf)  When the image taken already has good lighting and is for species identification purposes.  When you only want your image to look better artistically, regardless of how well it represents the original specimen. DO NOT DO THIS!

Lighting Adjustment: Levels  Go to Images > Adjustments > Levels  “Levels” window will open

Lighting Adjustment: Levels  When dragging white triangle to the left in input levels, image will lighten.  When dragging black triangle to the right in input levels, image will darken.

Lighting Adjustment: Levels  Dragging middle triangle (gray) in input levels to right will overall darken image and to left will overall lighten image.  Dragging black triangle under output levels will overall lighten image.

Lighting Adjustment: Levels  Dragging white triangle under output levels to left will overall darken image.

Lighting Adjustment: Shadows/Highlights  Image > Adjustments > Shadows/Highlights  Shadows/Highlights window will open

Lighting Adjustment: Shadows  Increasing Shadows amount (%)  Increasing Highlights amount (%)

Lighting Adjustment: Brightness/Contrast  Go to Images > Adjustments > Brightness/Contrast  Brightness/Contrast window will open and be set to zero.

Lighting Adjustment: Brightness  Increasing brightness – you can drag the slider or simply enter a positive integer in the box (ie 20)  Decreasing brightness – same as increasing, only the integers in this case will be negative (ie -20)

Lighting Adjustment: Contrast  Decreasing Contrast – once again, use the slider or enter a negative integer  Increasing Contrast – slider or positive integer

Sharpening: Smart Sharpen  Filter > Sharpen > Smart Sharpen  Smart Sharpen window will open

Sharpen: Smart Sharpen  To sharpen, adjust “Amount”  Left click and hold down will show original unsharpened image.  Unclick will show sharpened image.  Best amount settings are usually between 15 and 40%, although can vary depending on image.

Removing Background Blemishes  For aesthetic purposes  Remove uneven aspects in background  Select clone stamp tool

Removing Background Blemishes  In upper left hand corner of screen, clone stamp controls should be visible/  The hardness and size of clone stamp can be adjusted.  0% hardness and relatively large brush size is typically best  Use smaller brush size when working close to specimen

Removing Background Blemishes  Press “alt” key while clicking and holding down mouse in background area near blemish spot.  Click and hold down over blemish site which will change background to selected area.  Repeat to adjust.

More Analysis Techniques: Ruler  Select Analysis > Ruler Tool  Selected length of measurement is L1

More Analysis Techniques: Count  Select Analysis > Count Tool  Click to insert number