Best lossy archival format for 16-bit TIFF edits

Asked 12/24/2019

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I sometimes create large 16-bit TIFF files after editing, and I’d like to batch-convert them to a smaller lossy format for long-term storage while keeping as much tonal detail as possible, especially in shadows and highlights.

I tested JPEG, JPEG 2000, HEIC/HEIF, and WebP. In my tests, ImageMagick’s JPEG 2000 output gave poor detail, while Photoshop’s JPEG 2000 looked much better at a similar file size. HEIC seemed promising but may be limited to 8-bit in my workflow. I also found a workflow using a sigmoidal contrast transform before WebP compression, then reversing that transform when decoding back to TIFF.

What formats or workflows are practical for lossy archival of 16-bit TIFF images, and is wrapping a single image in H.265/x265 video a sensible idea?

Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0

Photography Stack Exchange contributor

6y ago

2 Answers

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May I suggest HEIF?

HEIF is the replacement for both JPEG and JPEG2000. It is effectively a single H.265 frame.

Don't store single-frame H.265 movies! Instead, use the proper file format that has been designed to use the same algorithms that H.265 uses.

Originally by user81735. Source · Licensed CC BY-SA 4.0

user81735

6y ago

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AI Answer

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A practical answer from the discussion is: use HEIF/HEIC rather than storing stills as single-frame H.265 video. HEIF is designed for still images and uses the same compression family, so it’s the proper container if you want that approach.

For JPEG 2000, the issue may be the particular encoder rather than the format itself: different encoders can produce very different results, and alternatives to ImageMagick’s JP2 encoder were suggested.

A tested workflow that gave strong results was WebP plus a sigmoidal transform before encoding, then reversing that transform when decoding back to 16-bit TIFF. That approach reportedly preserved highlight/shadow information well, avoided obvious artifacts and color shifts, kept the color profile, and produced a smaller file than the JPEG examples.

So, based on the answers:

  • don’t archive stills as single-frame x265 movies
  • HEIF/HEIC is the cleaner choice if you want H.265-based compression
  • if JPEG 2000 quality is poor, try a different JP2 encoder
  • WebP with a reversible sigmoidal pre/post process can work very well for compact lossy archival

UniqueBot

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6y ago

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