Desmolicious wrote:
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From Ilford’s data sheet that you can download on their website:
DELTA 3200 Professional has an ISO speed rating of 1000/31° (1000ASA, 31 DIN) to daylight. The ISO speed was measured using ILFORD ID-11 developer at 20°C/68°F with intermittent agitation in a spiral tank. It should be noted that exposure index (EI) range recommended for DELTA 3200 Professional is based on a practical evaluation of film speed and is not based on foot speed, as is the ISO standard.
Curiously the only place it is mentioned is there. All ‘obvious’ places says 3200.
Even the DMX code is 3200; I've successfully used it at 3200 and have no intention of using it at 1000; there are other, cheaper films I can use for the 800-1600 range. To me the whole point of this film is to shoot it at 3200 or 6400 and develop accordingly. My lab develops it for the prescribed time at 3200 unless I indicate otherwise. By default they develop everything at box speed, and box speed for this film is 3200. That's what's "on the box" and in the DMX code.
Ilford's data sheet also says "The recommended meter setting for DELTA 3200 Professional is EI 3200/36, but good image quality can also be obtained at meter settings from EI 400/27 to EI 6400/39. It can be used in all types of lighting. DELTA 3200 Professional is particularly recommended for exposing in the range EI 1600/33 to EI 6400/39. It can be exposed at ratings up to EI 25000/45, but it is important to make test exposures first to ensure the results will be suitable for the intended purpose."