Difference between revisions of "Picturing Plants - Photoshop"

Revision as of 13:28, 23 May 2013

Preparing digital images for print. Photo Quality prints need thousands of linear pixels. This means between 180 and 360 pixels per inch (ppi.) So, if a print is 10” long, you need 1800 – 3600 linear pixels for it to look good. (10” x 360=3600pixels).
Prepare images for the web. By contrast, images for the web or email need to be sized for screen resolution. Depending on the monitor you’ll need 800-1920 pixels to fill the screen.

Start Big: larger image files (both in file size and in overal number of pixels) provide you with higher quality images. You can always scale the image down but you can't scale it up.
Keep your original: These images are typically your highest quality image and you may need to go back to them from time to time.
File naming is important: Come up with a naming convention that helps you quickly identify the image without having to open it up. Names should include descriptive info, version, size or intended use.
- Example: Rainier_sunrise_1200_BW.psd - this file name tells me about the subject of the photo, the image size typically its width and any processing I've done, this one is a black and white version, it's file format is Photoshop.

Using the Epson scanners in the Computer Center. See: Scanning - Mac

Scan one drawing from a station connected to a scanner
Save as TIFF to your cubby on Orca. See: Connecting to Orca programs at File Space Overview
Go back to your station and copy your scanned image to your local hard drive and open locally in Photoshop

File > Open your scanned document in Photoshop
Keyboard shortcuts for navigating your image
- Zoom in/out: Cmd +/-
- Hand tool: Space Bar
Image > image Size to see the overall size and resolution of your image
- for print, image resolution should be at least 300 dpi
File > Save as choose Photoshop as the file format. Note the .psd extension.

If needed, rotate your image Image > Image Rotation
Crop and set the horizontal/vertical alignment for your image using the crop/align tool
- Note what happens if you choose Not to "delete cropped pixels"
- this relates directly to you Canvas size found in Image > Canvas Size

Image mode
- All images must be in RGB mode to print properly in the DIS. Go Image > Image mode and set the mode to RGB if it is not already
Adjust the image density (overall brightness/darkness of an image)
- Image > Adjustments > Brightness and Contrast is the most basic way to do this
- Image > Adjustments > Levels give you even more control and can work to clean-up scanned drawings or bring added depth the dull snapshots
- Recommended: try using Levels as an Adjustment Layer - Layer > New Adjustment layers > Levels

Working with Layers
- Creating A New Layer
- Moving/reordering layers
Selections can be made to fine-tune certain areas of your image. There are several tools that can be used to make a selection, all found on the tool bar.
- Try the Quick Selection Tool first.
Techniques for correction
- Healing Tools
Refine edges - if you are extracting an image from its background to place on a new background you may notice a "halo" around the cut-out image. This halo is called edge aliasing and can be eliminated by using the "Refine Edge" tool. See the refine edge tutorial for tips on using it effectively.

File > Save as choose Photoshop as the file format. Note the .psd extension.

@@ Line 39: / Line 39: @@
 #*'''Image > Adjustments > Brightness and Contrast''' is the most basic way to do this
 #*'''Image > Adjustments > Levels''' give you even more control and can work to clean-up scanned drawings or bring added depth the dull snapshots
-#*'''Adjustment layers''' are a more flexible option
+#*Recommended: try using Levels as an Adjustment Layer -  '''Layer > New Adjustment layers > Levels'''
 ===Image Touch up===