<human>: Does "Still, it remained difficult for manufactures to reliably determine film speeds, often only by comparing with competing products, so that an increasing number of modified semi-Scheiner-based systems started to spread, which no longer followed Scheiner's original procedures and thereby defeated the idea of comparability." contain the correct answer to "What method did manufacturers use much of the time to compare film speeds?"
OPTIONS:
- yes
- no
<bot>: yes