The ASCIIFoldingFilter is a superset of the ISOLatin1Filter - ISOLatin1 is deprecated. Here's the Javadoc from ASCIIFoldingFIlter. You did not mention which language you want to search.
Unforch, the ASCIIFoldingFilter is not mentioned on the Solr wiki. http://www.lucidimagination.com/search/?q=ASCIIFoldingFilter+ http://lucene.apache.org/java/2_9_1/api/all/org/apache/lucene/analysis/ASCIIFoldingFilter.html org.apache.lucene.analysis.ASCIIFoldingFilter This class converts alphabetic, numeric, and symbolic Unicode characters which are not in the first 127 ASCII characters (the "Basic Latin" Unicode block) into their ASCII equivalents, if one exists. Characters from the following Unicode blocks are converted; however, only those characters with reasonable ASCII alternatives are converted: C1 Controls and Latin-1 Supplement: http://www.unicode.org/charts/PDF/U0080.pdf Latin Extended-A: http://www.unicode.org/charts/PDF/U0100.pdf Latin Extended-B: http://www.unicode.org/charts/PDF/U0180.pdf Latin Extended Additional: http://www.unicode.org/charts/PDF/U1E00.pdf Latin Extended-C: http://www.unicode.org/charts/PDF/U2C60.pdf Latin Extended-D: http://www.unicode.org/charts/PDF/UA720.pdf IPA Extensions: http://www.unicode.org/charts/PDF/U0250.pdf Phonetic Extensions: http://www.unicode.org/charts/PDF/U1D00.pdf Phonetic Extensions Supplement: http://www.unicode.org/charts/PDF/U1D80.pdf General Punctuation: http://www.unicode.org/charts/PDF/U2000.pdf Superscripts and Subscripts: http://www.unicode.org/charts/PDF/U2070.pdf Enclosed Alphanumerics: http://www.unicode.org/charts/PDF/U2460.pdf Dingbats: http://www.unicode.org/charts/PDF/U2700.pdf Supplemental Punctuation: http://www.unicode.org/charts/PDF/U2E00.pdf Alphabetic Presentation Forms: http://www.unicode.org/charts/PDF/UFB00.pdf Halfwidth and Fullwidth Forms: http://www.unicode.org/charts/PDF/UFF00.pdf See: http://en.wikipedia.org/wiki/Latin_characters_in_Unicode The set of character conversions supported by this class is a superset of those supported by Lucene's ISOLatin1AccentFilter which strips accents from Latin1 characters. For example, 'à' will be replaced by 'a'.
