Decorated initials should be flagged by preceding the letter with an underscore character (_). Decorated initials are typically produced by means of a square woodcut containing the letter itself as well as decorative elements (flowers, vines, faces, animals, etc.). "Framed" initials--produced by overprinting a typographic letter with a decorative frame--should be treated as decorated initials too.
Simple "drop caps" should, however, continue to be captured without any special treatment. A drop cap is simply a large version of the letter (sometimes an elaborate and large version of the letter), but has no added pictorial elements; the latter distinguishes it from a decorated initial.
There may be a few examples about which it is difficult to decide: drop cap or decorated initial? If in doubt, leave out the "_".
(Capture by inserting "_" before letter)
|  Decorated A (_A) |  Decorated T (_T) |  Decorated S (_S) |  Decorated A (_A) |  Decorated A (_A) | 
|  Decorated F (_F) |  Decorated U (_U) |  Decorated W (_W) |  Decorated T (_T) |  Decorated W (_W) | 
|  Decorated I (_I) |  Decorated M (_M) |  Decorated R (_R) |  Decorated R (_R) |  Decorated C (_C) | 
|  Decorated S (_S) |  Decorated P (_P) |  Decorated V (_V) |  Decorated F (_F) | 
|  Decorated T (_T) |  Decorated T (_T) |  Decorated I (_I) |  Decorated K (_K) | 
|  Decorated S (_S) |  Decorated R (_R) |  Decorated G (_G) | |
|  Decorated M (_M) |  Decorated I (_I) |  Decorated M (_M) | |
|  Decorated W (_W) |  Decorated A (_A) | ||
|  Decorated C (_C) |  Decorated L (_L) |  Decorated W (_W) | |
|  Decorated H (_H) | |||
(Capture by inserting "_" before letter)
|  Framed V (treat as decorated V) |  Framed R (treat as decorated R) |  Framed S (treat as decorated S) | 
|  Framed I (treat as decorated I) |  Framed T (treat as decorated T) | |
(Capture by recording letter only, without special marking)
|  Drop-cap A |  Drop-cap E |  Drop-cap T |  Drop-cap U | 
|  Drop-cap T |