Why wouldn't exposure at EI 1000 be the first choice for "ILFORD DELTA 3200"?

[Colin O]

Starting with a few quotes from the Ilford data sheet...
 

Quote

 

ILFORD DELTA 3200 Professional is a high speed, black and white professional film. It is ideal for action and available light photography. It is designed to be exposed at EI 3200/36 and given extended development.

DELTA 3200 Professional has an ISO speed rating of 1000/31° (1000ASA, 31 DIN) to daylight.

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.

 

My question is, why does Ilford seem to particularly encourage exposure at EI 3200? It seems clear that this is a versatile film, useful for low-light scenarios. But in situations where EI 1000 would be adequate, and since that seems to be the actual native ISO of the film, then why wouldn't exposure at EI 1000 be the first recommendation?

Edited September 7, 2023 by Colin O
typo - 800 instead of 1000

[AJG]

Good question--many people are optimistic by nature about things like this, so I'm sure the film sells better with that ISO 3200 rating than it would with an honest 1000.  I long ago learned that pushing film through longer developing times or higher energy developers  increased contrast rather than increasing sensitivity, since that is built in when the film is made. I haven't used this film, but I am old enough to have tried Kodak 2475 Recording Film that was originally made for law enforcement/surveillance purposes.  It may have been adequate for evidence purposes in a court of law but it wasn't my aesthetic choice with its prominent grain.

[maris_rusis]

Here's an example of Ilford Delta 3200 shot at E.I. 1000 and given 3 stops extra to compensate for the red filter.
The high speed film was needed for hand held work while maintaining good detail and permitting small f-stops for adequate depth of field.

Near Cardrona, NZ

Gelatin-silver photograph on Ilford Classic VC FB photographic paper, image size 16.3cm X 21.5cm,
from a 68 format Ilford Delta 3200 negative exposed in a Fuji GSW680 camera fitted with a #25 red filter.

[glen_h]

Ilford makes some arguments based on the shape of the characteristic curve.

The usual ISO rating depends on the usual shape of the curve.

The question you are supposed to ask, is how it compares to Delta 400 at 1000.

This might be TMax 3200 instead of Delta 3200, as I have had both.

It is taken lit only by a full moon, though stars are visible.

It is in an FT3 at 1s and f/3.5, as I didn't have a cable release to take longer exposures without camera motion.

It is developed with the push to 25000 time, but I suspect that 3200 is closer to right.

Stars are visible in the sky.