Update app.py

app.py

@@ -177,7 +177,8 @@ with gr.Blocks(css="style.css") as demo:
     with gr.Column(elem_id="main_block"):
         with gr.Row(elem_id="board_row"):
             with gr.Group(elem_id="input_image_container", elem_classes="image_container" ):
-                image = gr.Sketchpad(type="pil", image_mode="L",container=False, height="100%", width="100%", value = empty_input_image, brush = gr.Brush(default_size="4"),
+                image = gr.Sketchpad(type="pil", image_mode="L",container=False, height="100%", width="100%", value = empty_input_image,
+                    brush = gr.Brush(default_size="4", colors=["#000000"], color_mode="fixed"),
                     # invert_colors=True, shape=(512, 512), brush_radius=4, 
                     interactive=True, show_download_button=True, elem_id="input_image", show_label=False)
                 gr.HTML("""<img src="file=assets/drawCta.png" id="draw_cta" alt="draw here image" />""",elem_id="draw_cta_container")