Before and after
Teal and orange
The last card is the predicate this page used to ship: it tested the output alone, so it counted every saturated pixel in the picture whether or not the transform had touched it. Both run on every pixel, so the difference is a number rather than an argument.
The circle is a constant L* 60, C* 40 ring in CIELAB. sRGB cannot hold all of it, so samples that fall outside are pulled in along the radius until they fit — 0 of 72 of them here. Reporting a hue shift without saying which samples had to be moved first would credit the transform with a displacement the gamut caused.
What each look is
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What stays
The .cube reader and writer, the trilinear interpolator and the 1D path are the job this tool exists to do, and they do it correctly. Everything above is about claims made around them.
What each number rests on
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The header carries the transform, the sample order and the number of levels the pipeline actually has. A .cube states no precision of its own, so a table written from 8 bits looks exactly like one written from 32 — six decimals either way.
Sources
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