This document describes the two compression schemes added by the Adobe Photoshop ® “Advanced TIFF” options dialog when saving TIFF files. The two options are ZIP (Deflate/Inflate) and JPEG. The next two sections give the details of the TIFF file structure when saving with these options. This document also describes the Image Source data tag written by Photoshop under tag number 37724. An update for Lab Images is included at the end of the document. WARNING: TIFF readers that encounter SubIFD (tag number 330) and a bit depth other than 8 should ignore the SubIFD’s found in the file. Readers are advised to cross reference terms and discussions found in this document with the TIFF 6.0 specification (TIFF6.pdf), the TIFF Technical Note for Adobe PageMaker ® 6.0 (TIFF-PM6.pdf), and the File Formats Specification for Adobe Photoshop ® (Photoshop File Formats.pdf).