DTF Glossary
Channel polarity
Channel polarity defines which numeric value means more ink or coating in a production plane. One workflow may treat black or 0 as maximum white ink, while another treats white or 255 as maximum coverage. A correct channel name with reversed polarity can produce the opposite mask, so bytes and mapping must be verified.
In practice
Do not infer polarity from a thumbnail or the word “White”. Inspect known regions: one that must receive full coverage, one that must receive none, and one controlled intermediate value. Then verify how the exact RIP queue maps those samples.
NestSheet’s DTF white convention is inverted relative to ordinary opacity, while varnish uses the opposite numeric direction. That is a file contract; the target device mapping still needs its own receipt.