diff --git a/implot_internal.h b/implot_internal.h
index d5decb5..5b24038 100644
--- a/implot_internal.h
+++ b/implot_internal.h
@@ -834,7 +834,7 @@ IMPLOT_API void AddTextVertical(ImDrawList *DrawList, ImVec2 pos, ImU32 col, con
 // Calculates the size of vertical text
 inline ImVec2 CalcTextSizeVertical(const char *text) { ImVec2 sz = ImGui::CalcTextSize(text); return ImVec2(sz.y, sz.x); }
 // Returns white or black text given background color
-inline ImU32 CalcTextColor(const ImVec4& bg) { return (bg.x * 0.299 + bg.y * 0.587 + bg.z * 0.114) > 0.729 ? IM_COL32_BLACK : IM_COL32_WHITE; }
+inline ImU32 CalcTextColor(const ImVec4& bg) { return (bg.x * 0.299 + bg.y * 0.587 + bg.z * 0.114) > 0.5 ? IM_COL32_BLACK : IM_COL32_WHITE; }
 
 // Clamps a label position so that it fits a rect defined by Min/Max
 inline ImVec2 ClampLabelPos(ImVec2 pos, const ImVec2& size, const ImVec2& Min, const ImVec2& Max) {