Set Area Fill Identity - Brother HL-1050 Technical Reference Manual

For example
(Source image is transparent)
With transparent

6.1.3. Set area fill identity

Esc*c#G (27)(42)(99)#(71)
 This command sets the pattern ID of a shading tone, a fill pattern or a user-defined pattern for subsequent
selection with the Set Pattern Type command.
 # 1 ~ 100 specify the percentage of a gray scale.
 # 1 ~ 6 select a fill pattern.
 # 1 ~ 32767 select a user-defined pattern.
 You can specify a gray scale tone from 1 to 100. To use the specified tone for shading you must then select
one of the two gray scale pattern options with the Set Pattern Type command.
For example
Pattern
Source image
Destination image
pattern
Possible results
Fill patterns
# = 1
# = 4
CHAPTER 2 PCL - 82
<1Bh><2Ah><63h>#<47h>
# = 2 # = 3
# = 5 # = 6
With opaque
pattern