Form 3B is a black and white sealed opacity chart. The top and bottom are white, middle section is black. Overall dimensions are 7-5/8 x 11-3/8 in (194 x 289 mm).
The header includes a writable area for recording:
- Date, Time
- Formula
- Batch Number
- Notes
A 1/4″ diameter hole is centred just under the top of the chart.