An example of a situation that demands contextual kerning in the Minion Pro font is the sequence of three characters "f.”" ("f", period, quotation mark), as is often found at the end of a quotation. Using the font's kerning tables, the quotation mark is too close to the "f", although without the period between them their spacing is adequate. The period, in other words, reduces their spacing instead of increasing it. The explanation is this: Without the period, their kerning is a positive 121 (expressed as 1000 units/em). The period's width is 228, but the kerning between "f" and the period is −5, and between the period and the quotation mark −138. The total is a positive 85, as opposed to the original 121: a net loss of 36 units, which explains why the quotation mark is now closer to the "f". Contextual kerning would recognize the sequence of three characters, and would increase one or both inter-character spaces. A similar problem exists with the letters "F", "P", "T", "V", "W", and "Y"; with comma rather than period; or with single rather than double quotation mark.