PROBLEM: Why do characters appear uneven or ragged on screen, even though they print beautifully?

ANSWER: The problem (or phenomenon) is caused by two factors: the ability of the TrueType(r) rasterizer built into Windows to display the outline characters as they are drawn, and the level of hinting in the font. The first factor is really a question of putting a round peg in a square hole. Fonts are created as a series of character outlines, drawn with corners and curves. The screen is made up of 800 x 600 or more square pixels (picture elements) which are the smallest unit of screen space that Windows can control. Square pixels often cannot represent a curve or a diagonal well. Windows uses the built-in TrueType rasterizer to convert outlines to pixels. Windows must decide, on the fly as it interprets each character, whether to turn on or turn off a particular pixel on screen. If you can imagine part of a character outline with a slope not quite horizontal or not quite vertical, you will realize that the line is moving from one row or column of pixels to the next. Windows has to decide whether to turn on one or both pixels. Sometimes it does and sometimes it does not. This results in three types of problems: characters that look bolder on screen than the character next to them; characters whose different parts have different, uneven, widths; and characters that look different, or have changing unevenness, at different point sizes.

To demonstrate the second and third problems, type a row of the uppercase letter 'B' starting with a very small point size (maybe point size 6) and getting larger one point at a time up to about 24 points. (This test will not work with Times New Roman or other Windows supplied fonts.) You will notice that the B will change shape as it gets larger. Different parts of the B will have different (changing) widths, and the upper and lower bowls of the B will change their relative shapes and sizes. What you are seeing is the rasterizer interpreting the letter differently for each size. When the vertical stem of the B suddenly changes width or heaviness from one size to the next, the rasterizer is deciding to turn on or off one extra column of pixels. When you see curved parts of the B look uneven at one size and better at the next size, you are seeing the rasterizer having trouble deciding when to turn on a new row or column of pixels and when to leave them off. When one of the two bowls suddenly changes its shape and size relative to the other bowl, you are seeing the rasterizer deciding to jump from one row or column of pixels to the next. All this is happening because the rasterizer does not have enough hinting information to know exactly which pixels to turn on at any particular point size.

Font creators can overcome some of the 'unknowns' related to the second factor influencing screen display by building into the font what are called 'hints'. Hinting information is provided for the rasterizer either by the software that generates the font (normal hinting) or by additional software after the font is generated (delta hinting). The software needed for delta hinting costs many thousands of dollars to purchase, learn, and use. Most font creation software, including the programs we use, contains basic hinting algorithms, so our fonts have basic hints in them. But to get the beautiful, consistent look on screen of a Windows system font such as Times New Roman, developers must add delta hinting to their fonts. Only the largest font foundries can afford this.

The point to remember is that no matter how a TrueType or PostScript(r) font looks on screen, it will print beautifully. In fact, this is where Linguist's Software excels. Our fonts are designed for exceptionally high quality printing, and will print to as high a quality as your printer is capable.