Kino
Subscriber
It actually does have a anti halation layer, but it's designed for a printer lamp bulb, not camera shooting, so it doesn't work as well.
"Product description: ORWO DN21 (Duplicating Negative) is a low-speed, black and white film,
specifically designed for the production of black & white duplicate negatives from master positives,
or internegatives from reversal negatives. DN21 has panchromatic sensitivity, high sharpness,
and produces well-balanced grey values. There is a new AHU-Layer (Anti Halation Under-Layer)
between the emulsion layer and the clear base which will be uncolored during the processing.
Compare to: Eastman Fine Grain Duplicating Panchromatic
"Product description: ORWO DN21 (Duplicating Negative) is a low-speed, black and white film,
specifically designed for the production of black & white duplicate negatives from master positives,
or internegatives from reversal negatives. DN21 has panchromatic sensitivity, high sharpness,
and produces well-balanced grey values. There is a new AHU-Layer (Anti Halation Under-Layer)
between the emulsion layer and the clear base which will be uncolored during the processing.
Compare to: Eastman Fine Grain Duplicating Panchromatic