* a signature
     */
    public PdfDictionary getSignatureDictionary(String name) {
        getSignatureNames();
        name = getTranslatedFieldName(name);
        if (!sigNames.containsKey(name))
            return null;
        Item item = fields.get(name);
        PdfDictionary merged = item.getMerged(0);
        return merged.getAsDict(PdfName.V);
    }