Nabeel Al-Shamma

Adobe Reader and Acrobat have had font smoothing for numerous releases. Early on it was an option that needed to be enabled in preferences. We now have it on by default. But, the default setting is for CRT's. You need to explicitly change the settings for LCD displays:

1. Go to preferences (Cntrl-K or Cmd-K)
2. Choose "Page Display" under "Categories" on the upper left corner of the dialog
3. For "Rendering" select "For Laptop/LCD Screens" for the "Smooth Text" option

Font smoothing for CRT's is good, but I see a noticeable difference when I turn on smoothing for LCD's. We use a number of techniques to optimize for LCD's. One major one is to take advantage of the greater resolution of LCD's due to the layout of the parts of a pixel. On a CRT, there are three blurry dots that make up a pixel. On an LCD, there are red, green and blue subpixels next to each other, usually in the horizontal row. We can take advantage of this to position characters (I'm going to use the word characters, but I should really be saying glyphs to be technically accurate) with greater fidelity, essentially to 1/3 pixel resolution. With font smoothing, we've always had the ability to position characters at subpixel positions, typically at 1/4 pixel resolution for CRT's. This improves character spacing.

We also play a number of tricks with the scaling and sampling of characters, and with stem alignment with pixels. Control of color is critical, both in the overall color of the text (which is essentially the number of pixels turned on and the uniformity of "grayness" of a paragraph), and in the minimization of color ghosting (which can make your text look like it is decorated with Christmas lights).

Please try turning on smoothing for LCD Screens. I'd love to hear about how it changes your reading experience.