• Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint
Share this Page URL
Help

Chapter 5. Optimizing Grayscale Images > Hidden Features to the Rescue

Hidden Features to the Rescue

To achieve maximum contrast without sacrificing detail, Adobe created a hidden feature in the Levels dialog box. It's known as Threshold mode because it acts like the Threshold dialog box that we used in Bonus Chapter 1, “Line Art Scanning” on the CD at the back of this book. This feature allows you to see exactly which areas are becoming black or white, and it's the key to ensuring that you don't sacrifice detail. To get to the hidden feature, hold down the Option key (Mac) or Alt key (Windows) when you move the upper-right or upper-left sliders in the Levels dialog box.

When you move the upper-left slider with Threshold mode turned on, your image should turn white until the slider touches the first bar on the histogram; then small black areas should start to appear. These are the areas that will become pure black. With most images, you'll want to make sure you don't force a large concentrated area to black, so move the slider until only small areas appear. You also want to make sure the areas that are becoming black still contain detail. Detail will show up looking like noise (not the kind you hear—the kind you see on an old television when you don't have an antenna hooked up), so make sure those small areas also look noisy. You'll need to repeat this process with the upper-right slider to make sure you get optimal contrast (Figures 5.9 to 5.18).


PREVIEW

                                                                          

Not a subscriber?

Start A Free Trial


  
  • Creative Edge
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint