Presentation on theme: "Post Editing: Lightroom & Photoshop by Tim Andersen"— Presentation transcript:
Post Editing: Lightroom & Photoshop by Tim Andersen http://www.andersenimages.com
Higher quality image out-of-camera = Better outcome after “Photoshopping” an image. What affects image quality? Beyond equipment & knowing how to use your camera… Shooting in JPG vs RAW: RAW Data – RAW files contain additional information about your image that will be lost if you save straight to JPG. 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 does not damage the image (lossless).
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. BitsTotal Shades 1-bit2 shades 2-bit4 shades 3-bit8 shades 4-bit16 shades 5-bit32 shades 6-bit64 shades 7-bit128 shades 8-bit256 shades 9-bit512 shades 10-bit1,024 shades 11-bit2,048 shades 12-bit4,096 shades 13-bit8,192 shades 14-bit16,384 shades 15-bit32,768 shades
Let’s take a look at just the Red Channel from the image below (recall that a photo has 3 different channels—Red, Green and Blue). 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
Start out at 8-bit—the bit depth of a JPG image…
Bottom line, the more bits you have the more shades of a color that can be represented in the image. More is better! 14-bit 16,384 Shades of Red 14-bit 16,384 Shades of Red 8-bit 256 Shades of Red 8-bit 256 Shades of Red 4-bit 16 Shades of Red 4-bit 16 Shades of Red 1-bit 2 Shades of Red 1-bit 2 Shades of Red
Reduces the size of your image file on disk, but compromises the overall quality of the image. It’s analogous to making a photocopy on a Xerox machine—the copy iss a close reproduction of the original, but not an exact copy. Consider the zoomed-in section of the following image…
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.
Note the “compression artifacts,” which introduce a “ghosting” effect around high-contrast areas; and tend to give the photo blocky appearance.
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, 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 Xerox 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.
Lightroom Multi-Purpose: Edit photos… …and do it fast! Limited Manipulation Built-in RAW support Robust Organization and Categorization tools Presentation tools (slideshow, photo book, web gallery Other Software: GIMP (Open Source / Free) Aperture (Mac) Corel PaintShop/CorelDraw Google Picasa Apple iPhoto Photoshop Elements Basic photo editing tools Organization and Presentation tools Adobe Camera Raw (ACR) Limited capabilities Adobe Camera Raw (ACR) Limited capabilities Photoshop CS/CC Sole Purpose: Provide a superior and robust set of photo editing tools for photographers and designers alike. Edit and Manipulate photos Adobe Camera Raw (ACR) Required to work with RAW Adobe Camera Raw (ACR) Required to work with RAW Adobe Bridge File Browser and Organizer Adobe Bridge File Browser and Organizer
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