Type XI is brighter than Type IV at the reference geometry. On a 4 m × 6 m gantry seen from close range, that advantage can disappear — and the 12% price difference buys nothing the driver can see.
The reason is angularity. A gantry panel is read at a much wider observation angle than a sign at the roadside, and Type VIII is the grade specified for wide-angle performance. Type XI wins on a long, straight approach with a narrow angle — Type VIII wins when the geometry is wide.
The practical rule: read the observation angle off the site drawing before reading the price list. If the tender names Diamond Grade, quote it and attach the report — but say in the same email what the geometry implies, because the re-sign after first inspection costs more than the film ever did.
More in this section.
DOT-C2 explained: what an inspector actually measures on a trailer
The pattern is prescribed, the 250 RA is a floor, and there is no DOT certificate — what gets checked and how.
Applying sheeting below 10 °C: why edges lift and how to prevent it
Adhesive tack collapses in the cold, the edge takes the load, and a pressure roller will not rescue a cold panel.
All insights
Every record in this section, in one list.