In a recent federal decision the court held that "n4 "Tagged Image File Format, '[is] a file format that is easily searchable for specific terms.'" Johnson v. Allstate Ins. Co., 2012 U.S. Dist. LEXIS 148282 (S.D. Ill. Oct. 16, 2012) citing to the third circuit Race Tires case which does not stand for this proposition.
TIFF files are noted for being nonsearchable, unless they are OCR'ed, whose accuracy can range, depending on the quality of the source material, from 50% to 99%.