# GFCLRLUM System Variable [GstarCAD 2026](Help%20System/GSTARCAD/2026/Index.md) → [System Variables](Help%20System/GSTARCAD/2026/System%20Variables/(System%20Variables).md) → [G](Help%20System/GSTARCAD/2026/System%20Variables/G/(G).md) ## Function Description: The GFCLRLUM system variable is used to control the light level and dark level in single color gradient fill. | | | | --- | --- | | Type | Real | | Saved in | Not saved | | Initial value | 1.0000 | | Range | 0.0 ~ 1.0 | A tint gradient transitions toward white and a shade gradient transition toward black. --- [Original help](https://www.gstarcad.net/help/GstarCAD_2026_en-US/detail/systemVariables_Ggsv/GFCLRLUM.html) · © Gstarsoft Co., Ltd.