104e3a106f99c1a444d9a1fa948924dbcdab1cd2
3
Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
|
|
e9b3598841 |
Add five Ilford stocks, and say plainly that they are constructed
Build and test / Desktop (Linux) (push) Successful in 20m48s
Build and test / Layer separation (push) Successful in 27s
Traceability / Requirement traces (push) Failing after 25s
🐳 Android image / Build and push (push) Successful in 2s
Build and test / android-image (push) Successful in 2s
Build and test / Android (aarch64) (push) Failing after 33m33s
They were asked for and they are here, but not on the same footing as the
Kodak profiles, and the files say so in their first line.
What I had claimed, and had to withdraw: that Delta 100 is "quoted around 9"
and HP5 "around 12". Ilford publish no such figures. The word granularity does
not occur anywhere in their technical information -- grain is described as
"fine" and "finest" and nothing more. That claim was in this crate's
documentation as though it came from a datasheet; it is corrected there too.
Two further traps found while looking:
- Kodak colour negatives publish Print Grain Index, not RMS granularity.
PGI is a perceptual scale from viewer surveys -- 25 is roughly the
threshold of visibility, four units a just-noticeable difference -- and
Kodak state it cannot be compared to RMS. So a Portra number cannot be
dropped into the granularity field, and none has been.
- RMS proper is published mostly for black-and-white, reversal and motion
picture stocks. Every shipped stock therefore still carries the same
default, which means grain does not yet tell one film from another. That
is per-stock data, not code, and is now written down where somebody will
find it.
So the Ilford profiles are built rather than extracted, and each part rests on
something different:
speed published and exact -- ISO 400/27 for HP5 is a fact
contrast ISO 6:1993's normal development, average gradient 0.62
spectral borrowed from Kodak Double-X, a *measured* panchromatic
negative, shifted by the speed difference. Conventional
panchromatic sensitisation is much alike across black-and-white
films, and this is far better founded than reading pixels off a
printed curve
silver neutral, which is not an approximation: developed silver
absorbs flat, and Double-X's measurement is flat
granularity estimated, ordered by each film's known relative grain
They render as a film of that speed and contrast. They are not a measurement
of that emulsion, and the two stocks that share a speed differ only in the
estimated part.
`every_shipped_stock_bakes` is tightened to match, because a constructed
profile fails in a way a measured one does not: the curve parses, bakes, and
sits entirely off one end of its own exposure range, rendering every frame
black or blown while passing a finiteness check. It now asserts mid-grey lands
somewhere photographic and that the tone response runs the way the stock's
kind says it should.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
|
||
|
|
3b5952769b |
Emit floats an f32 can hold, and drop the format! that formats nothing
CI runs cargo fmt --check and clippy -D warnings, and this branch had never been through either. Both would have failed it. The bulk was the generated colour tables: eight significant figures where an f32 carries about 7.2, so the eighth is noise that rounds away at compile time and clippy's excessive_precision says so 109 times over. Fixed in the generator rather than only in the file, so it stays fixed -- and the file is trimmed in place rather than re-derived, because regenerating it needs a colour-science stack that has nothing to do with the defect. The format! in the composer is mine too, from extracting the rendering tail: the braces in it were escaped because the text used to live inside a larger template, and once extracted the escapes are noise and the call formats nothing. Also here, and clearly not mine: an unused import and a shadowed binding in dr-gpu, and an unused import in a test. They are pre-existing -- clippy has been failing on master before this branch existed, on lints like is_multiple_of that arrived with a toolchain rather than with anyone's code. Fixed because CI cannot go green around them, and called out because a merge commit is a bad place to quietly edit someone else's crate. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |
||
|
|
6d18517d28 |
Ship every stock that exists, black and white included
Three profiles was what the first cut needed to prove the model. This is the rest of the open data: 23 camera stocks and 9 papers, which is all of spektrafilm. Black and white was the gap, and it turned out not to be a gap in the data -- it was a gap in where I looked. Upstream's `main` has 28 colour profiles and nothing monochrome; `dev` has three more, and they are Tri-X, Double-X and the 2302 print film they go onto. So the answer to "do we have B&W" was yes all along, and it needed the dev branch rather than a fortnight digitising Ilford's datasheet graphs by eye. Those three are pinned to `dev` per stock; the colour stocks stay on the released branch. A monochrome profile is single-channel -- one emulsion, not three -- and spreading that one layer across all three is exact rather than an approximation: three layers with identical sensitivity and identical curves respond identically, which is what one layer does. The dye is the trap. The renderer *sums* the three layers' contributions, so replicating it unchanged renders every frame three times too dense -- neutrally, and therefore plausibly. A third each reconstructs the single emulsion, and two tests hold both halves: that the densities stay equal, and that they sum to one emulsion and not three. Double-X and 2302 ship five curves apiece, measured at five development times -- 4 to 12 minutes for Double-X. That is push and pull processing as measured data. The standard 6.5 minutes is what ships; the rest is in the upstream file waiting for a control to ask for it. Two stocks are `support: film` and are nevertheless what a negative is printed *onto*: the cine projection films 2383 and 2393, which the Vision3 stocks print to. Filtering the picker on support alone offered a projection stock as something to load in a camera, so it filters on stage, with a test saying so. The picker had to change shape twice over. Chips were right for three stocks and off the edge of a 280px column at twenty-four, and the column that replaced them was a thousand pixels standing between the photographer and every slider below. It is a disclosure now: one row carrying the answer, opened to change it, closed again on choosing. That is the opposite of the argument this panel used to take the lids off its sliders, and deliberately so -- an instrument you compare wants to be visible, and a list you consult once wants to be out of the way. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |