1. Dynamite Digital Images: A Primer by Melodie Putnam Oregon State University

2. Outline  Basics of digital photography  Resolution  File format  Editing: cropping  Focus  Lighting

3. Goal: To provide an image which allows identification of the subject

4. Resolution (optical sharpness) Of camera: Number of photosites (pixels) 1600 columns x 1200 rows = 1.92 x 10 6 = 2 megapixel camera Nikon Coolpix 8800 = 3,264 x 2,448 pixels (8 Mp) to 1,280 x 960 (1 Mp)

5. Resolution Of monitor: Pixels per linear inch = ppi Computer monitor = 72-96 ppi Images at 72 ppi on the computer will look about the same as images > 72 ppi

6. 300 ppi 9 Mp 72 ppi 156 Kp difference = ability to enlarge

9. Resolution Of printer: Good quality = 300 ppi

10. Viewing images on screen If 1 monitor pixel = 1 image pixel then image is displayed at 100% (even if entire image is not on the screen)

11. File compression 1 pixel can have up to 24 bits of color 24 bits x 1,600 x 1,200 pixels = ~ 6 Mb Color images are large files! Compression saves space Joint Photographic Experts Group (JPEG)

14. Poor image resolution

15. File format Tagged Image File Format (TIFF) = standard for lossless compression (or no compression) JPEG = compressed images (may be losses)

16. Editing - Save files to be edited as TIFF files opening and saving images with compression will result in cumulative compression (losses) each time

17. Editing Crop the image to clarify

23. Editing - Save files as TIFF files - Crop, frame, and edit - Save edited version as jpeg files

24. Focus Autofocus Works best with contrast between subject and background

26. Focus Autofocus Does NOT work well: - Subject is same color as background - Objects are different distances from camera

28. Manual focus Use with close-ups Use when subjects are at difference distances

30. Lighting Avoid harsh light that produces shadows Images that are too dark mask details Watch background glare

31. Washed out & out of focus

32. Background  Avoid white  Lighter backgrounds for dark subjects  Darker backgrounds for light subjects

34. Add a size reference (ruler is best)

35. Size reference is OK, but camera is too far away

36. Saving images - Give your image a descriptive name e.g. “pumpkin stem Walters farm 8-12-06” vs. DSCN0347

37. Finally, Critically review your images before sending them. If images are: - out of focus - cluttered - poorly lit - not illustrative of the situation, problem or pest - too far away… Don’t expect a diagnosis

38. Authorship Melodie Putnam Director, Oregon State University Plant Clinic 1089 Cordley Hall 2701 SW Campus Way Corvallis, OR 97331 Phone: 541-737-3472 Fax: 541-737-2412 http://www.science.oregonstate.edu/ bpp/Plant_Clinic/index.htm putnamm@science.oregonstate.edu

39. National Plant Diagnostic Network Thank you! www.wpdn.org www.npdn.org