Measured film base for Fujifilm Superia X-TRA 400, read off the clear rebate under the three narrow bands. These are the numbers the app uses as the denominator for every frame on a roll of this stock.
#Base density, in counts
| Channel | Band | Counts |
|---|---|---|
| Red | 665 nm | 220.6 |
| Green | 525 nm | 419.7 |
| Blue | 450 nm | 566.5 |
#How it was measured
Superia400 · 10/10 frames · ±5/7/7 ct · pooled rebate
That line is the provenance: which frames it was pooled from, and the spread between them. A base is not a constant of the emulsion — it is a measurement of a batch, with a tolerance.
Note
This stock also has a white-light pair measured: R 244.4 · G 385.1 · B 503.9. That is what the same base reads as under white light rather than three bands — useful only for comparison, since the channels overlap there.
#If yours reads differently
It may well. Emulsion batches vary — a green slope of [1, 1.8, 1] was confirmed independently on two different stocks — and your light is not necessarily the one these were read under. Post what you measured and on what rig, and it becomes a second data point rather than a disagreement.