8-bit Greyscale Twin (PNG)
8-bit PNG twin of the linear 16-bit greyscale ramp — compare banding after truncation.
Specifications
- Width
- 256
- Height
- 256
- Bit Depth
- 8
- Role
- truncated twin of 16-bit ramp
What is a .png file?
PNG (Portable Network Graphics) is a raster image format using lossless DEFLATE compression. It supports full 8- or 16-bit-per-channel truecolor, palette, and greyscale modes with an optional alpha channel, but no animation. It is the standard choice for screenshots, logos, and graphics with sharp edges or transparency.
How to use this file
Use an example PNG to test image decoders, alpha-compositing, thumbnail generators, and format converters, or to verify that a pipeline preserves transparency and color depth on round-trip.
How to use this file for testing
“8-bit Greyscale Twin (PNG)” is a deterministic Novus Examples fixture for Linear 16-bit / HDR-ish, Conversion testing. 16-bit linear TIFF ramps and twins (not PQ/HDR10 display masters) for deep-colour loaders, truncation, and tone-map pipelines.
Documented properties for this file: 256×256 · truncated twin of 16-bit ramp · 8-bit. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
For image AI or enhancement tools, run the model or filter on this file and diff against the clean or ground-truth companion in the same group when available. Keep seeds and documented damage parameters in your evaluation notes so regressions are attributable.
Code examples
<img src="linear-8bit-grey-twin.png" alt="Example image" width="640" loading="lazy">Related files
- tiffLinear 16-bit Grey TIFF (deflate)64×64 linear 16-bit greyscale TIFF with deflate — Wave H depth for high bit-depth loaders.
- tiffLinear 16-bit Grey TIFF (LZW)LZW twin of the Wave H linear 16-bit greyscale TIFF.
- tiffLinear 16-bit Checker TIFF64×64 linear 16-bit checkerboard TIFF for bit-depth and downsample tests.
- tiffLinear 16-bit Hot-Edge TIFFLinear 16-bit TIFF with a dark edge and near-clip field — tone-map edge case.
- png16-bit Grayscale PNG (deep colour)A 16-bit (deep-colour) grayscale PNG holding a smooth 0–65535 gradient — for testing high-bit-depth support and spotting banding when a tool truncates to 8-bit.
- svgAnimated Spinner (SVG)An animated loading spinner using SMIL (animateTransform) — a self-contained animated SVG for testing whether a renderer or converter handles SVG animation, and how it rasterises an animated frame.
Generated by generation/images_hdr_linear.py. Free for any use, no attribution required — license.