The effect shown with -1 seems to be the "default", extremely high and low values for mat_fullbright are all the same as using -1 and various numbers between the known 0 through 81 values are identical to -1 as well. List of mat_fullbright values that have the default effect:
- All negative numbers
- 7
- 9
- 18 & 19
- 25 through 29 (inclusive)
- 32 through 39 (inclusive)
- 45
- 50 through 59 (inclusive)
- 61 through 64 (inclusive)
- 67 through 69 (inclusive)
- 71 through 79 (inclusive)
- All numbers above 81
