Photography 101

1. Photography 101 Post Editing: Lightroom & Photoshop by Tim Andersen

2. Start out with a high quality image! • The higher quality image you start out with, the more you’ll be able to do with that image when editing in an application like Photoshop or Lightroom. • What affects image quality? • Beyond knowing how to use your camera… • Shooting in JPG vs RAW: • RAW files contain a lot of extra information about your image that can result in a better final image. Saving to JPG, you effectively lose this extra information. • Bit Depth – describes how much data is stored for each pixel in an image. RAW almost always has a greater bit depth than JPG. • Compression – shrinks the size of an image on your computer, but can compromise image quality. JPG always compresses in a way that will damage your image to some degree (lossy). RAW can compress, too, but in a way that doesn’t damage the image (lossless).

3. Dissecting An ImageOne Way To Look At It Image 3 Color Channels Blue Channel Red Channel Green Channel A bunch of pixels A bunch of pixels A bunch of pixels Bits of Data (usually 8-14 bits) Bits of Data (usually 8-14 bits) Bits of Data (usually 8-14 bits)

4. Dissecting An ImageAnother Way To Look At It

5. “Bit Depth” of an image Individual pixels in an image are stored as a series of “bits” of data. The more bits of data you cram into each pixel, the more varying shades of a particular color you can store. The more shades of color you have, the more you can manipulate an image in a program like Photoshop or Lightroom before it begins to degrade. This is particularly important when doing things like increasing contrast or brightening up the shadowy area of an image. More aggressive your editing, the more “wiggle room” you give yourself if you shoot at a higher bit depth. As the table to the right shows, for each additional bit you add, you double the number of shades. JPG Raw

6. Red Color Channel at Different Bit Depths Let’s take a look at just the Red Channel from the image below. The following slides demonstrate what this image’s Red Channel might look like if we shot it with a camera that would let you control the bit depth from 1 bit to 14 bits (in reality, no camera shoots at a bit depth less than 8-bits). Original Image Red Channel Only

7. Red Color Channel at Different Bit Depths Bottom line, the more bits you have the more shades of a color that can be represented in the image. More is better!

8. JPG Compression Reduces the size of your image file on disk, but compromises the overall quality of the image. It’s analogous to making a photocopy of a document—the copy’s a close reproduction of the original, but not an exact copy. Consider the zoomed-in section of the following image…

9. JPG – Worst Case Re-save a JPG image multiple times at a low quality setting. Because JPG saves and compresses in a “lossy” manner, you lose some image quality after each save. Before

10. JPG – Worst Case Note the “compression artifacts,” which introduce a “ghosting” effect around high-contrast areas; and tend to give the photo grid look. After

11. JPG Compression Bottom line, JPG is a useful file format and certainly recommended for images that you don’t intend to ever edit later on; or if you just don’t have the hard drive space for RAW, BMP, TIFF, etc. If you do plan on further processing a JPG image, just understand that editing them—especially in a more aggressive manner—tends to bring out/amplify compression artifacts, which will affect your final image. Also, when you Open  Edit  Save over a JPG file multiple times, the compression artifacts’ effects will become worse and worse (again, going back to the photo copier, consider making a copy of a copy, and then a copy of a copy of a copy, etc…). A good rule of thumb is to never save to JPG for a file that think you might do further editing to. Instead, us a file format like PSD (Photoshop), TIFF, BMP, PNG—any format that doesn’t suffer from “lossy” compression like JPG.

12. Photoshop & Lightroom • Photoshop Elements 12 • $99 New / 79 Upgrade • Scaled down version of Photoshop CC, suitable for most basic editing tasks. • Does provide “Adobe Camera RAW” to edit RAW files (again, scaled back).