--- a/Resources/OrthancWSIClearCache.py	Wed Feb 19 17:54:25 2025 +0100
+++ b/Resources/OrthancWSIClearCache.py	Thu Mar 13 16:58:51 2025 +0100
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 
 # Orthanc - A Lightweight, RESTful DICOM Store
 # Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
@@ -40,10 +40,13 @@
     exit(-1)
 
 
-METADATA=4200
+METADATA = [
+    4200,  # For versions <= 0.7 of the plugin
+    4201,  # For versions >= 1.0 of the plugin
+]
 
 
-def RunHttpRequest(uri, method, body = None):
+def RunHttpRequest(uri, method, ignore_errors, body = None):
     http = httplib2.Http()
     headers = { }
 
@@ -65,7 +68,7 @@
                                  body = body,
                                  headers = headers)
 
-    if resp.status != 200:
+    if not ignore_errors and resp.status != 200:
         raise Exception('Cannot %s on URL %s, HTTP status %d '
                         '(Is Orthanc running? Is there a password?)' % 
                         (method, url, resp.status))
@@ -73,8 +76,9 @@
         return content.decode('utf8')
 
 
-for instance in json.loads(RunHttpRequest('/instances', 'GET')):
+for instance in json.loads(RunHttpRequest('/instances', 'GET', ignore_errors = False)):
     print('Clearing cache for instance %s' % instance)
-    RunHttpRequest('/instances/%s/metadata/%s' % (instance, METADATA), 'DELETE')
+    for metadata in METADATA:
+        RunHttpRequest('/instances/%s/metadata/%s' % (instance, metadata), 'DELETE', ignore_errors = True)
 
 print('The WSI cache was successfully cleared')

--- a/ViewerPlugin/Plugin.cpp	Wed Feb 19 17:54:25 2025 +0100
+++ b/ViewerPlugin/Plugin.cpp	Thu Mar 13 16:58:51 2025 +0100
@@ -27,6 +27,7 @@
 #include "DicomPyramidCache.h"
 #include "IIIF.h"
 #include "RawTile.h"
+#include "../Framework/ColorSpaces.h"
 #include "../Framework/Inputs/DecodedTiledPyramid.h"
 #include "../Framework/Inputs/OnTheFlyPyramid.h"
 #include "../Framework/Inputs/DecodedPyramidCache.h"
@@ -405,6 +406,12 @@
 }
 
 
+static bool IsNear(float a, float b)
+{
+  return std::abs(a - b) < 100.0f * std::numeric_limits<float>::epsilon();
+}
+
+
 extern "C"
 {
   ORTHANC_PLUGINS_API int32_t OrthancPluginInitialize(OrthancPluginContext* context)
@@ -439,6 +446,49 @@
     Orthanc::Logging::Initialize(context);
 #endif
 
+    try
+    {
+      /**
+
+         C.10.7.1.1 Encoding of CIELab Values
+
+         Attributes such as Graphic Layer Recommended Display CIELab
+         Value (0070,0401) consist of three unsigned short values:
+
+         An L value linearly scaled to 16 bits, such that 0x0000
+         corresponds to an L of 0.0, and 0xFFFF corresponds to an L of
+         100.0.
+
+         An a* then a b* value, each linearly scaled to 16 bits and
+         offset to an unsigned range, such that 0x0000 corresponds to
+         an a* or b* of -128.0, 0x8080 corresponds to an a* or b* of
+         0.0 and 0xFFFF corresponds to an a* or b* of 127.0
+
+       **/
+
+      OrthancWSI::LABColor lab;
+      if (!OrthancWSI::LABColor::DecodeDicomRecommendedAbsentPixelCIELab(lab, "65535\\0\\0") ||
+          !IsNear(lab.GetL(), 100.0f) ||
+          !IsNear(lab.GetA(), -128.0f) ||
+          !IsNear(lab.GetB(), -128.0f))
+      {
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_InternalError);
+      }
+
+      if (!OrthancWSI::LABColor::DecodeDicomRecommendedAbsentPixelCIELab(lab, "0\\32896\\65535") ||
+          !IsNear(lab.GetL(), 0.0f) ||
+          !IsNear(lab.GetA(), 0.0f) ||
+          !IsNear(lab.GetB(), 127.0f))
+      {
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_InternalError);
+      }
+    }
+    catch (Orthanc::OrthancException& e)
+    {
+      LOG(ERROR) << "Exception in startup tests: " << e.What();
+      return -1;
+    }
+
     // Limit the number of PNG transcoders to the number of available
     // hardware threads (e.g. number of CPUs or cores or
     // hyperthreading units)