Phase One introduced IIQ, short for Intelligent Image Quality, in 2008 alongside the P65+ digital back \u2014 part of a line of medium-format camera backs aimed at studio, landscape, and cultural-heritage photography where extremely high resolution and dynamic range matter more than file size or shooting speed. The format was built specifically to handle sensor readouts far larger than typical 35mm-format cameras produce, with current Phase One systems reaching resolutions above 150 megapixels.<\/p>
IIQ comes in two working variants that matter for storage planning: IIQ L applies lossless compression, keeping every bit of sensor data intact for archival-grade capture, while IIQ S applies visually lossless compression that shrinks files by roughly 40 to 60 percent with negligible perceptible quality loss \u2014 a deliberate trade-off for workflows generating enormous data volumes per shoot.<\/p>
Because Phase One remains an active, specialized vendor with Capture One as its flagship processing software, IIQ is comparatively well supported today, and mainstream tools like Adobe Camera Raw track new back releases reasonably closely. Even so, a DAM handling Phase One assets should keep IIQ L files as the true archival master rather than IIQ S, and lean on DNG or fully rendered derivatives for team members without a Capture One license.<\/p>","protected":false},"excerpt":{"rendered":"
IIQ is Phase One’s proprietary raw format for its high-resolution medium-format digital backs, introduced in 2008 and available in lossless (IIQ L) and visually-lossless-compressed (IIQ S) variants.<\/p>\n","protected":false},"author":0,"featured_media":0,"template":"","meta":{"footnotes":"","faq":[{"question":"What are the two IIQ variants and why does the distinction matter for DAM storage budgeting?","answer":"IIQ L uses lossless compression for zero-quality-loss capture, while IIQ S uses visually lossless compression that cuts file sizes roughly 40-60% with minimal perceptible quality impact, directly relevant to storage budgeting for very large medium-format libraries."},{"question":"Which IIQ variant should a DAM keep as the archival master?","answer":"The IIQ L lossless master, generating DNG or rendered derivatives for search, preview, and cross-team access outside Capture One licenses."},{"question":"What resolutions does IIQ need to accommodate?","answer":"Phase One's large-area CCD and CMOS backs range up to 150+ megapixels in current systems, so a DAM handling IIQ needs to plan storage and preview generation around very large file sizes."},{"question":"Is IIQ decoder support at risk of vendor abandonment?","answer":"Low risk currently. IIQ is a professional, actively maintained format from a currently operating vendor, though Capture One remains the reference tool for full-fidelity processing of high-end Phase One backs."},{"question":"When was IIQ introduced?","answer":"2008, announced with the Phase One P65+ digital back."},{"question":"What bit depth does IIQ capture at?","answer":"16 bits per channel."},{"question":"Is there a public specification for IIQ?","answer":"No. The format embeds camera metadata and preview data but has no public specification, similar to most other proprietary medium-format raw formats."},{"question":"What open-source tools can decode IIQ?","answer":"darktable via RawSpeed with camera-specific additions for Phase One backs, and RawTherapee with libraw-based IIQ decoding."}],"checked_date":"2026-08-07","sources":[{"statement":"IIQ is Phase One's proprietary raw format, with IIQ Large using lossless compression and IIQ Small using visually lossless compression that reduces file size by roughly 40-60%","source_name":"Phase One, Intelligent Image Quality (IIQ) overview","url":"https:\/\/www.phaseone.com\/imaging-quality-performance\/intelligent-image-quality-iiq\/","checked":"2026-08-07"},{"statement":"The Phase One P65+ digital back was announced in 2008 and paired with the IIQ raw format","source_name":"Photography Bay, hands-on coverage of Phase One 645DF, P65+ and P40+","url":"https:\/\/photographybay.com\/2009\/10\/22\/hands-on-phase-one-645df-p-65-and-p-40\/","checked":"2026-08-07"},{"statement":"Phase One digital backs shoot IIQ files that are opened natively in Capture One, with Adobe Camera Raw support varying by back generation","source_name":"Capture One support, Phase One RAW files option","url":"https:\/\/support.captureone.com\/hc\/en-us\/articles\/360002564358-Phase-One-RAW-files-option","checked":"2026-08-07"}],"kicker":"","fact_checker":0,"reading_time":0,"revisions":[],"seo_title":"","seo_description":"","noindex":false,"ext":"iiq","full_name":"Intelligent Image Quality","vendor_name":"Phase One","introduced":"2008, announced with the Phase One P65+ digital back","container_notes":"IIQ stores unprocessed sensor data at 16 bits per channel from Phase One's large-area CCD and CMOS backs, which range up to 150+ megapixels in current systems. It ships in two variants: IIQ L, using lossless compression for zero-quality-loss capture, and IIQ S, using visually lossless compression that cuts file sizes roughly 40\u201360% with minimal perceptible quality impact \u2014 a distinction directly relevant to DAM storage budgeting for very large medium-format libraries. The format embeds camera metadata and preview data but has no public specification.","open_with":[{"platform":"Windows \/ macOS","how":"Capture One, Phase One's own software and the primary professional tool for IIQ, with full support for both compression variants"},{"platform":"Windows \/ macOS","how":"Adobe Camera Raw \/ Lightroom Classic, with support that varies by digital back generation"},{"platform":"Cross-platform, open source","how":"darktable, via RawSpeed with camera-specific additions for Phase One backs"},{"platform":"Cross-platform, open source","how":"RawTherapee, with libraw-based IIQ decoding"}],"archive_advice":"IIQ is a professional, actively maintained format from a currently operating vendor, so decoder abandonment risk is relatively low, but Capture One remains the reference tool for full-fidelity processing of high-end Phase One backs. For DAM archival, keep the IIQ L (lossless) master and generate DNG or rendered derivatives for search, preview, and cross-team access outside Capture One licenses.","related":[2613,2602,2596,2611,2592,2599],"tool_link":""},"silo":[23],"class_list":["post-2612","format","type-format","status-publish","hentry","silo-formats"],"_links":{"self":[{"href":"https:\/\/picajet.com\/articles\/wp-json\/wp\/v2\/format\/2612","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/picajet.com\/articles\/wp-json\/wp\/v2\/format"}],"about":[{"href":"https:\/\/picajet.com\/articles\/wp-json\/wp\/v2\/types\/format"}],"version-history":[{"count":3,"href":"https:\/\/picajet.com\/articles\/wp-json\/wp\/v2\/format\/2612\/revisions"}],"predecessor-version":[{"id":3670,"href":"https:\/\/picajet.com\/articles\/wp-json\/wp\/v2\/format\/2612\/revisions\/3670"}],"wp:attachment":[{"href":"https:\/\/picajet.com\/articles\/wp-json\/wp\/v2\/media?parent=2612"}],"wp:term":[{"taxonomy":"silo","embeddable":true,"href":"https:\/\/picajet.com\/articles\/wp-json\/wp\/v2\/silo?post=2612"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}