diff --git a/server/src/wled_controller/api/routes/picture_targets.py b/server/src/wled_controller/api/routes/picture_targets.py
index 0946846..c2a3fe3 100644
--- a/server/src/wled_controller/api/routes/picture_targets.py
+++ b/server/src/wled_controller/api/routes/picture_targets.py
@@ -15,6 +15,7 @@ from wled_controller.api.dependencies import (
     get_pattern_template_store,
     get_picture_source_store,
     get_picture_target_store,
+    get_pp_template_store,
     get_processor_manager,
     get_template_store,
 )
@@ -34,6 +35,7 @@ from wled_controller.api.schemas.picture_targets import (
 )
 from wled_controller.config import config
 from wled_controller.core.capture_engines import EngineRegistry
+from wled_controller.core.filters import FilterRegistry, ImagePool
 from wled_controller.core.processor_manager import ProcessorManager, ProcessingSettings
 from wled_controller.core.screen_capture import (
     calculate_average_color,
@@ -564,6 +566,7 @@ async def test_kc_target(
     pattern_store: PatternTemplateStore = Depends(get_pattern_template_store),
     processor_manager: ProcessorManager = Depends(get_processor_manager),
     device_store: DeviceStore = Depends(get_device_store),
+    pp_template_store=Depends(get_pp_template_store),
 ):
     """Test a key-colors target: capture a frame, extract colors from each rectangle."""
     import httpx
@@ -665,6 +668,27 @@ async def test_kc_target(
         else:
             raise HTTPException(status_code=400, detail="Unsupported picture source type")
 
+        # 3b. Apply postprocessing filters (if the picture source has a filter chain)
+        pp_template_ids = chain.get("postprocessing_template_ids", [])
+        if pp_template_ids and pp_template_store:
+            img_array = np.array(pil_image)
+            image_pool = ImagePool()
+            for pp_id in pp_template_ids:
+                try:
+                    pp_template = pp_template_store.get_template(pp_id)
+                except ValueError:
+                    logger.warning(f"KC test: PP template {pp_id} not found, skipping")
+                    continue
+                for fi in pp_template.filters:
+                    try:
+                        f = FilterRegistry.create_instance(fi.filter_id, fi.options)
+                        result = f.process_image(img_array, image_pool)
+                        if result is not None:
+                            img_array = result
+                    except ValueError:
+                        logger.warning(f"KC test: unknown filter '{fi.filter_id}', skipping")
+            pil_image = Image.fromarray(img_array)
+
         # 4. Extract colors from each rectangle
         img_array = np.array(pil_image)
         h, w = img_array.shape[:2]