Lossless compression algorithm that shrinks file size without degrading image data — used in TIFF and archival formats. Essential for DCP-mastering.
Anyone working with digital image data will inevitably encounter LZW — a compression method that has been indispensable in the VFX and photography pipeline since the 1980s. The abbreviation stands for Lempel-Ziv-Welch, named after its developers. The method is lossless: it finds recurring patterns in the image data and replaces them with shorter codes without altering a single pixel. This makes LZW ideal for mastering, archiving, and any production step where image quality is non-negotiable.
In practice, VFX supervisors and colorists primarily encounter LZW in TIFF files — the standard for intermediate material. When archiving 4K plates or color grades, LZW-compressed TIFFs quickly save 30–50% storage space without noticeably slowing down the editing suite or render farm. Decompression happens smoothly in RAM. Older systems — and this is the crucial point — handle LZW more stably than modern codec variants like JPEG 2000 or ProRes. That's why LZW is still found in established studios today, not out of nostalgia, but out of practical reliability. A 2K DPX sequence with LZW loads faster into your compositing application because decompression works on standard hardware.
The catch: LZW is not optimal for every purpose. With highly compressed sources or extreme motion, the method achieves lower compression rates than specialized video codecs. And in modern pipelines, where one is more likely to work with ProRes RAW, OpenEXR, or H.265, LZW plays a subordinate role. Nevertheless — if you take over a legacy project or a studio works with archives from the 2000s: LZW is often the standard then. It's worth knowing the basics, because files quickly swell if you save TIFF uncompressed.
Practical tip: Test LZW for your next archiving task. For 8-bit material and anything that doesn't require an extreme color space, it offers a solid price-performance ratio — saved storage, full quality, no recompression needed. In a RAW workflow or when working with very wide color spaces, however, it's better to choose uncompressed or opt for newer alternatives like ZIP or specialized image codecs.