diff --git a/intern/cycles/app/cycles_standalone.cpp b/intern/cycles/app/cycles_standalone.cpp
index 69518684103..510ed7e92f9 100644
--- a/intern/cycles/app/cycles_standalone.cpp
+++ b/intern/cycles/app/cycles_standalone.cpp
@@ -539,7 +539,7 @@ using namespace ccl;
 
 int main(const int argc, const char **argv)
 {
-  log_init(argv[0]);
+  log_init(nullptr);
   path_init();
   options_parse(argc, argv);
 
diff --git a/intern/cycles/app/cycles_xml.cpp b/intern/cycles/app/cycles_xml.cpp
index f4aa8e759cb..68bc744668f 100644
--- a/intern/cycles/app/cycles_xml.cpp
+++ b/intern/cycles/app/cycles_xml.cpp
@@ -22,8 +22,10 @@
 #include "scene/shader_graph.h"
 #include "scene/shader_nodes.h"
 
+#include "util/log.h"
 #include "util/path.h"
 #include "util/projection.h"
+#include "util/string.h"
 #include "util/transform.h"
 #include "util/xml.h"
 
@@ -261,14 +263,12 @@ static void xml_read_shader_graph(XMLReadState &state, Shader *shader, const xml
           }
 
           if (!output) {
-            fprintf(stderr,
-                    "Unknown output socket name \"%s\" on \"%s\".\n",
-                    from_node_name.c_str(),
-                    from_socket_name.c_str());
+            LOG(ERROR) << "Unknown output socket name \"" << from_node_name << "\" on \""
+                       << from_socket_name << "\".";
           }
         }
         else {
-          fprintf(stderr, "Unknown shader node name \"%s\".\n", from_node_name.c_str());
+          LOG(ERROR) << "Unknown shader node name \"" << from_node_name << "\"";
         }
 
         if (graph_reader.node_map.find(to_node_name) != graph_reader.node_map.end()) {
@@ -281,14 +281,12 @@ static void xml_read_shader_graph(XMLReadState &state, Shader *shader, const xml
           }
 
           if (!input) {
-            fprintf(stderr,
-                    "Unknown input socket name \"%s\" on \"%s\".\n",
-                    to_socket_name.c_str(),
-                    to_node_name.c_str());
+            LOG(ERROR) << "Unknown input socket name \"" << to_socket_name << "\" on \""
+                       << to_node_name << "\"";
           }
         }
         else {
-          fprintf(stderr, "Unknown shader node name \"%s\".\n", to_node_name.c_str());
+          LOG(ERROR) << "Unknown shader node name \"" << to_node_name << "\"";
         }
 
         /* connect */
@@ -297,7 +295,7 @@ static void xml_read_shader_graph(XMLReadState &state, Shader *shader, const xml
         }
       }
       else {
-        fprintf(stderr, "Invalid from or to value for connect node.\n");
+        LOG(ERROR) << "Invalid from or to value for connect node.";
       }
 
       continue;
@@ -320,17 +318,17 @@ static void xml_read_shader_graph(XMLReadState &state, Shader *shader, const xml
           snode = OSLShaderManager::osl_node(graph.get(), state.scene, filepath, "");
 
           if (!snode) {
-            fprintf(stderr, "Failed to create OSL node from \"%s\".\n", filepath.c_str());
+            LOG(ERROR) << "Failed to create OSL node from \"" << filepath << "\"";
             continue;
           }
         }
         else {
-          fprintf(stderr, "OSL node missing \"src\" attribute.\n");
+          LOG(ERROR) << "OSL node missing \"src\" attribute.";
           continue;
         }
       }
       else {
-        fprintf(stderr, "OSL node without using --shadingsys osl.\n");
+        LOG(ERROR) << "OSL node without using --shadingsys osl.";
         continue;
       }
     }
@@ -345,15 +343,16 @@ static void xml_read_shader_graph(XMLReadState &state, Shader *shader, const xml
       const NodeType *node_type = NodeType::find(node_name);
 
       if (!node_type) {
-        fprintf(stderr, "Unknown shader node \"%s\".\n", node.name());
+        LOG(ERROR) << "Unknown shader node \"" << node.name() << "\"";
         continue;
       }
       if (node_type->type != NodeType::SHADER) {
-        fprintf(stderr, "Node type \"%s\" is not a shader node.\n", node_type->name.c_str());
+        LOG(ERROR) << "Node type \"" << node_type->name << "\" is not a shader node";
         continue;
       }
       if (node_type->create == nullptr) {
-        fprintf(stderr, "Can't create abstract node type \"%s\".\n", node_type->name.c_str());
+        LOG(ERROR) << "Can't create abstract node type \""
+                   << "\"";
         continue;
       }
 
@@ -698,7 +697,7 @@ static void xml_read_state(XMLReadState &state, const xml_node node)
     }
 
     if (!found) {
-      fprintf(stderr, "Unknown shader \"%s\".\n", shadername.c_str());
+      LOG(ERROR) << "Unknown shader \"" << shadername << "\"";
     }
   }
 
@@ -717,7 +716,7 @@ static void xml_read_state(XMLReadState &state, const xml_node node)
     }
 
     if (!found) {
-      fprintf(stderr, "Unknown object \"%s\".\n", objectname.c_str());
+      LOG(ERROR) << "Unknown object \"" << objectname << "\"";
     }
   }
 
@@ -808,7 +807,7 @@ static void xml_read_scene(XMLReadState &state, const xml_node scene_node)
     }
 #endif
     else {
-      fprintf(stderr, "Unknown node \"%s\".\n", node.name());
+      LOG(ERROR) << "Unknown node \"" << node.name() << "\"";
     }
   }
 }
@@ -832,7 +831,7 @@ static void xml_read_include(XMLReadState &state, const string &src)
     xml_read_scene(substate, cycles);
   }
   else {
-    fprintf(stderr, "%s read error: %s\n", src.c_str(), parse_result.description());
+    LOG(ERROR) << "\"" << src << "\" read error: " << parse_result.description();
     exit(EXIT_FAILURE);
   }
 }
diff --git a/intern/cycles/app/opengl/window.cpp b/intern/cycles/app/opengl/window.cpp
index ebe034aa6c7..672978f39f3 100644
--- a/intern/cycles/app/opengl/window.cpp
+++ b/intern/cycles/app/opengl/window.cpp
@@ -7,6 +7,7 @@
 
 #include "app/opengl/window.h"
 
+#include "util/log.h"
 #include "util/string.h"
 #include "util/thread.h"
 #include "util/version.h"
@@ -66,7 +67,7 @@ static void window_display_text(int /*x*/, int /*y*/, const char *text)
   static string last_text;
 
   if (text != last_text) {
-    printf("%s\n", text);
+    LOG(INFO_IMPORTANT) << text;
     last_text = text;
   }
 #endif
@@ -291,7 +292,7 @@ void window_main_loop(const char *title,
                               height,
                               SDL_WINDOW_RESIZABLE | SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN);
   if (V.window == nullptr) {
-    fprintf(stderr, "Failed to create window: %s\n", SDL_GetError());
+    LOG(ERROR) << "Failed to create window: " << SDL_GetError();
     return;
   }
 
diff --git a/intern/cycles/blender/logging.cpp b/intern/cycles/blender/logging.cpp
index ca92da52412..5aa7ea47e4e 100644
--- a/intern/cycles/blender/logging.cpp
+++ b/intern/cycles/blender/logging.cpp
@@ -29,6 +29,7 @@ void CCL_log_init()
             CLG_log_str(log_type, CLG_SEVERITY_WARN, file_line, func, msg);
             return;
           case ccl::INFO:
+          case ccl::INFO_IMPORTANT:
           case ccl::WORK:
           case ccl::STATS:
           case ccl::DEBUG:
diff --git a/intern/cycles/blender/python.cpp b/intern/cycles/blender/python.cpp
index d4a8ade302a..406fa1694d6 100644
--- a/intern/cycles/blender/python.cpp
+++ b/intern/cycles/blender/python.cpp
@@ -17,7 +17,7 @@
 #include "util/debug.h"
 
 #include "util/guiding.h"
-#include "util/md5.h"
+#include "util/log.h"
 #include "util/openimagedenoise.h"
 #include "util/path.h"
 #include "util/string.h"
@@ -727,7 +727,7 @@ static PyObject *set_device_override_func(PyObject * /*self*/, PyObject *arg)
     BlenderSession::device_override = DEVICE_MASK_ONEAPI;
   }
   else {
-    fprintf(stderr, "\nError: %s is not a valid Cycles device.\n", override.c_str());
+    LOG(ERROR) << override << " is not a valid Cycles device.";
     Py_RETURN_FALSE;
   }
 
diff --git a/intern/cycles/blender/volume.cpp b/intern/cycles/blender/volume.cpp
index 4c50ddef792..43e61e6d46d 100644
--- a/intern/cycles/blender/volume.cpp
+++ b/intern/cycles/blender/volume.cpp
@@ -10,6 +10,8 @@
 #include "blender/sync.h"
 #include "blender/util.h"
 
+#include "util/log.h"
+
 #include "BKE_volume_grid.hh"
 
 CCL_NAMESPACE_BEGIN
@@ -140,16 +142,15 @@ class BlenderSmokeLoader : public ImageLoader {
       }
     }
     else {
-      fprintf(stderr,
-              "Cycles error: unknown volume attribute %s, skipping\n",
-              Attribute::standard_name(attribute));
+      LOG(ERROR) << "Unknown volume attribute " << Attribute::standard_name(attribute)
+                 << "skipping ";
       fpixels[0] = 0.0f;
       return false;
     }
 #else
     (void)pixels;
 #endif
-    fprintf(stderr, "Cycles error: unexpected smoke volume resolution, skipping\n");
+    LOG(ERROR) << "Unexpected smoke volume resolution, skipping";
     return false;
   }
 
diff --git a/intern/cycles/device/cuda/device.cpp b/intern/cycles/device/cuda/device.cpp
index 062fcd8f04c..96978638472 100644
--- a/intern/cycles/device/cuda/device.cpp
+++ b/intern/cycles/device/cuda/device.cpp
@@ -109,7 +109,7 @@ void device_cuda_info(vector<DeviceInfo> &devices)
   CUresult result = device_cuda_safe_init();
   if (result != CUDA_SUCCESS) {
     if (result != CUDA_ERROR_NO_DEVICE) {
-      fprintf(stderr, "CUDA cuInit: %s\n", cuewErrorString(result));
+      LOG(ERROR) << "CUDA cuInit: " << cuewErrorString(result);
     }
     return;
   }
@@ -117,7 +117,7 @@ void device_cuda_info(vector<DeviceInfo> &devices)
   int count = 0;
   result = cuDeviceGetCount(&count);
   if (result != CUDA_SUCCESS) {
-    fprintf(stderr, "CUDA cuDeviceGetCount: %s\n", cuewErrorString(result));
+    LOG(ERROR) << "CUDA cuDeviceGetCount: " << cuewErrorString(result);
     return;
   }
 
@@ -128,7 +128,7 @@ void device_cuda_info(vector<DeviceInfo> &devices)
 
     result = cuDeviceGetName(name, 256, num);
     if (result != CUDA_SUCCESS) {
-      fprintf(stderr, "CUDA cuDeviceGetName: %s\n", cuewErrorString(result));
+      LOG(ERROR) << "CUDA cuDeviceGetName: " << cuewErrorString(result);
       continue;
     }
 
diff --git a/intern/cycles/device/cuda/device_impl.cpp b/intern/cycles/device/cuda/device_impl.cpp
index d96e5b62e0f..1c498143120 100644
--- a/intern/cycles/device/cuda/device_impl.cpp
+++ b/intern/cycles/device/cuda/device_impl.cpp
@@ -8,6 +8,7 @@
 #  include <cstdio>
 #  include <cstdlib>
 #  include <cstring>
+#  include <iomanip>
 
 #  include "device/cuda/device_impl.h"
 
@@ -339,19 +340,13 @@ string CUDADevice::compile_kernel(const string &common_cflags,
   const int nvcc_cuda_version = cuewCompilerVersion();
   LOG(INFO) << "Found nvcc " << nvcc << ", CUDA version " << nvcc_cuda_version << ".";
   if (nvcc_cuda_version < 101) {
-    printf(
-        "Unsupported CUDA version %d.%d detected, "
-        "you need CUDA 10.1 or newer.\n",
-        nvcc_cuda_version / 10,
-        nvcc_cuda_version % 10);
+    LOG(WARNING) << "Unsupported CUDA version " << nvcc_cuda_version / 10 << "."
+                 << nvcc_cuda_version % 10 << ", you need CUDA 10.1 or newer";
     return string();
   }
   if (!(nvcc_cuda_version >= 102 && nvcc_cuda_version < 130)) {
-    printf(
-        "CUDA version %d.%d detected, build may succeed but only "
-        "CUDA 10.1 to 12 are officially supported.\n",
-        nvcc_cuda_version / 10,
-        nvcc_cuda_version % 10);
+    LOG(WARNING) << "CUDA version " << nvcc_cuda_version / 10 << "." << nvcc_cuda_version % 10
+                 << "CUDA 10.1 to 12 are officially supported.";
   }
 
   double starttime = time_dt();
@@ -376,9 +371,9 @@ string CUDADevice::compile_kernel(const string &common_cflags,
       cubin.c_str(),
       common_cflags.c_str());
 
-  printf("Compiling %sCUDA kernel ...\n%s\n",
-         (use_adaptive_compilation()) ? "adaptive " : "",
-         command.c_str());
+  LOG(INFO_IMPORTANT) << "Compiling " << ((use_adaptive_compilation()) ? "adaptive " : "")
+                      << "CUDA kernel ...";
+  LOG(INFO_IMPORTANT) << command;
 
 #  ifdef _WIN32
   command = "call " + command;
@@ -398,7 +393,8 @@ string CUDADevice::compile_kernel(const string &common_cflags,
     return string();
   }
 
-  printf("Kernel compilation finished in %.2lfs.\n", time_dt() - starttime);
+  LOG(INFO_IMPORTANT) << "Kernel compilation finished in " << std::fixed << std::setprecision(2)
+                      << time_dt() - starttime << "s";
 
   return cubin;
 }
diff --git a/intern/cycles/device/device.cpp b/intern/cycles/device/device.cpp
index 59476c9eb66..281e5fb86a6 100644
--- a/intern/cycles/device/device.cpp
+++ b/intern/cycles/device/device.cpp
@@ -49,6 +49,15 @@ uint Device::devices_initialized_mask = 0;
 
 Device::~Device() noexcept(false) = default;
 
+void Device::set_error(const string &error)
+{
+  if (!have_error()) {
+    error_msg = error;
+  }
+  LOG(ERROR) << error;
+  fflush(stderr);
+}
+
 void Device::build_bvh(BVH *bvh, Progress &progress, bool refit)
 {
   assert(bvh->params.bvh_layout == BVH_LAYOUT_BVH2);
diff --git a/intern/cycles/device/device.h b/intern/cycles/device/device.h
index b28ef4565e3..1f3de252314 100644
--- a/intern/cycles/device/device.h
+++ b/intern/cycles/device/device.h
@@ -158,14 +158,7 @@ class Device {
   {
     return !error_message().empty();
   }
-  virtual void set_error(const string &error)
-  {
-    if (!have_error()) {
-      error_msg = error;
-    }
-    fprintf(stderr, "%s\n", error.c_str());
-    fflush(stderr);
-  }
+  virtual void set_error(const string &error);
   virtual BVHLayoutMask get_bvh_layout_mask(const uint kernel_features) const = 0;
 
   /* statistics */
diff --git a/intern/cycles/device/hip/device.cpp b/intern/cycles/device/hip/device.cpp
index 2d023a3d1b9..da5b50746ac 100644
--- a/intern/cycles/device/hip/device.cpp
+++ b/intern/cycles/device/hip/device.cpp
@@ -129,7 +129,7 @@ void device_hip_info(vector<DeviceInfo> &devices)
   hipError_t result = device_hip_safe_init();
   if (result != hipSuccess) {
     if (result != hipErrorNoDevice) {
-      fprintf(stderr, "HIP hipInit: %s\n", hipewErrorString(result));
+      LOG(ERROR) << "HIP hipInit: " << hipewErrorString(result);
     }
     return;
   }
@@ -137,7 +137,7 @@ void device_hip_info(vector<DeviceInfo> &devices)
   int count = 0;
   result = hipGetDeviceCount(&count);
   if (result != hipSuccess) {
-    fprintf(stderr, "HIP hipGetDeviceCount: %s\n", hipewErrorString(result));
+    LOG(ERROR) << "HIP hipGetDeviceCount: " << hipewErrorString(result);
     return;
   }
 
@@ -154,7 +154,7 @@ void device_hip_info(vector<DeviceInfo> &devices)
 
     result = hipDeviceGetName(name, 256, num);
     if (result != hipSuccess) {
-      fprintf(stderr, "HIP :hipDeviceGetName: %s\n", hipewErrorString(result));
+      LOG(ERROR) << "HIP hipDeviceGetName: " << hipewErrorString(result);
       continue;
     }
 
diff --git a/intern/cycles/device/hip/device_impl.cpp b/intern/cycles/device/hip/device_impl.cpp
index 15fe203b853..f51ab81d305 100644
--- a/intern/cycles/device/hip/device_impl.cpp
+++ b/intern/cycles/device/hip/device_impl.cpp
@@ -7,6 +7,7 @@
 #  include <cstdio>
 #  include <cstdlib>
 #  include <cstring>
+#  include <iomanip>
 
 #  include "device/hip/device_impl.h"
 
@@ -345,9 +346,8 @@ string HIPDevice::compile_kernel(const uint kernel_features, const char *name, c
                                  fatbin.c_str(),
                                  common_cflags.c_str());
 
-  printf("Compiling %sHIP kernel ...\n%s\n",
-         (use_adaptive_compilation()) ? "adaptive " : "",
-         command.c_str());
+  LOG(INFO_IMPORTANT) << "Compiling " << ((use_adaptive_compilation()) ? "adaptive " : "")
+                      << "HIP kernel ...";
 
 #  ifdef _WIN32
   command = "call " + command;
@@ -367,7 +367,8 @@ string HIPDevice::compile_kernel(const uint kernel_features, const char *name, c
     return string();
   }
 
-  printf("Kernel compilation finished in %.2lfs.\n", time_dt() - starttime);
+  LOG(INFO_IMPORTANT) << "Kernel compilation finished in " << std::fixed << std::setprecision(2)
+                      << time_dt() - starttime << "s";
 
   return fatbin;
 }
diff --git a/intern/cycles/device/hiprt/device_impl.cpp b/intern/cycles/device/hiprt/device_impl.cpp
index 015f6e4335f..2d29d153dfb 100644
--- a/intern/cycles/device/hiprt/device_impl.cpp
+++ b/intern/cycles/device/hiprt/device_impl.cpp
@@ -4,8 +4,10 @@
 
 #ifdef WITH_HIPRT
 
-#  include "device/hiprt/device_impl.h"
+#  include <iomanip>
+
 #  include "device/hip/util.h"
+#  include "device/hiprt/device_impl.h"
 #  include "kernel/device/hiprt/globals.h"
 
 #  include "util/log.h"
@@ -152,9 +154,9 @@ string HIPRTDevice::compile_kernel(const uint kernel_features, const char *name,
 
   if (!use_adaptive_compilation()) {
     const string fatbin = path_get(string_printf("lib/%s_rt_%s.hipfb.zst", name, arch.c_str()));
-    VLOG(1) << "Testing for pre-compiled kernel " << fatbin << ".";
+    LOG(INFO) << "Testing for pre-compiled kernel " << fatbin << ".";
     if (path_exists(fatbin)) {
-      VLOG(1) << "Using precompiled kernel.";
+      LOG(INFO) << "Using precompiled kernel.";
       return fatbin;
     }
   }
@@ -171,9 +173,9 @@ string HIPRTDevice::compile_kernel(const uint kernel_features, const char *name,
   const string fatbin = path_cache_get(path_join("kernels", fatbin_file));
   const string hiprt_include_path = path_join(source_path, "kernel/device/hiprt");
 
-  VLOG(1) << "Testing for locally compiled kernel " << fatbin << ".";
+  LOG(INFO) << "Testing for locally compiled kernel " << fatbin << ".";
   if (path_exists(fatbin)) {
-    VLOG(1) << "Using locally compiled kernel.";
+    LOG(INFO) << "Using locally compiled kernel.";
     return fatbin;
   }
 
@@ -208,11 +210,8 @@ string HIPRTDevice::compile_kernel(const uint kernel_features, const char *name,
   const int hipcc_hip_version = hipewCompilerVersion();
   LOG(INFO) << "Found hipcc " << hipcc << ", HIP version " << hipcc_hip_version << ".";
   if (hipcc_hip_version < 40) {
-    printf(
-        "Unsupported HIP version %d.%d detected, "
-        "you need HIP 4.0 or newer.\n",
-        hipcc_hip_version / 10,
-        hipcc_hip_version % 10);
+    LOG(WARNING) << "Unsupported HIP version " << hipcc_hip_version / 10 << "."
+                 << hipcc_hip_version % 10 << ", you need HIP 4.0 or newer.\n";
     return string();
   }
 
@@ -235,7 +234,7 @@ string HIPRTDevice::compile_kernel(const uint kernel_features, const char *name,
   options.append(" -D WITH_NANOVDB");
 #  endif
 
-  printf("Compiling  %s and caching to %s", source_path.c_str(), fatbin.c_str());
+  LOG(INFO_IMPORTANT) << "Compiling " << source_path << " and caching to " << fatbin;
 
   double starttime = time_dt();
 
@@ -258,7 +257,8 @@ string HIPRTDevice::compile_kernel(const uint kernel_features, const char *name,
     return string();
   }
 
-  printf("Kernel compilation finished in %.2lfs.\n", time_dt() - starttime);
+  LOG(INFO_IMPORTANT) << "Kernel compilation finished in " << std::fixed << std::setprecision(2)
+                      << time_dt() - starttime << "s";
 
   return fatbin;
 }
@@ -267,7 +267,7 @@ bool HIPRTDevice::load_kernels(const uint kernel_features)
 {
   if (hipModule) {
     if (use_adaptive_compilation()) {
-      VLOG(1) << "Skipping HIP kernel reload for adaptive compilation, not currently supported.";
+      LOG(INFO) << "Skipping HIP kernel reload for adaptive compilation, not currently supported.";
     }
     return true;
   }
diff --git a/intern/cycles/device/queue.cpp b/intern/cycles/device/queue.cpp
index 10b81a6fe99..80b25046024 100644
--- a/intern/cycles/device/queue.cpp
+++ b/intern/cycles/device/queue.cpp
@@ -2,15 +2,15 @@
  *
  * SPDX-License-Identifier: Apache-2.0 */
 
-#include "device/queue.h"
+#include <iomanip>
+
 #include "device/kernel.h"
+#include "device/queue.h"
 
 #include "util/algorithm.h"
 #include "util/log.h"
 #include "util/time.h"
 
-#include <iomanip>
-
 CCL_NAMESPACE_BEGIN
 
 DeviceQueue::DeviceQueue(Device *device) : device(device)
diff --git a/intern/cycles/graph/node_type.cpp b/intern/cycles/graph/node_type.cpp
index 5ade312e48a..2a1aab1fd84 100644
--- a/intern/cycles/graph/node_type.cpp
+++ b/intern/cycles/graph/node_type.cpp
@@ -4,6 +4,7 @@
 
 #include "graph/node_type.h"
 
+#include "util/log.h"
 #include "util/transform.h"
 
 CCL_NAMESPACE_BEGIN
@@ -214,7 +215,7 @@ NodeType *NodeType::add(const char *name_, CreateFunc create_, Type type_, const
   const ustring name(name_);
 
   if (types().find(name) != types().end()) {
-    fprintf(stderr, "Node type %s registered twice!\n", name_);
+    LOG(ERROR) << "Node type " << name_ << " registered twice";
     assert(0);
     return nullptr;
   }
diff --git a/intern/cycles/graph/node_type.h b/intern/cycles/graph/node_type.h
index 48dda1b75dd..6abf3ee35fc 100644
--- a/intern/cycles/graph/node_type.h
+++ b/intern/cycles/graph/node_type.h
@@ -5,6 +5,7 @@
 #pragma once
 
 #include "graph/node_enum.h"
+
 #include "util/array.h"  // IWYU pragma: keep
 #include "util/map.h"
 #include "util/param.h"
diff --git a/intern/cycles/graph/node_xml.cpp b/intern/cycles/graph/node_xml.cpp
index ac7270c815f..aa4a06059bb 100644
--- a/intern/cycles/graph/node_xml.cpp
+++ b/intern/cycles/graph/node_xml.cpp
@@ -7,6 +7,7 @@
 #  include "graph/node_xml.h"
 #  include "graph/node.h"
 
+#  include "util/log.h"
 #  include "util/string.h"
 #  include "util/transform.h"
 
@@ -158,10 +159,8 @@ void xml_read_node(XMLReader &reader, Node *node, const xml_node xml_node)
           node->set(socket, value);
         }
         else {
-          fprintf(stderr,
-                  "Unknown value \"%s\" for attribute \"%s\".\n",
-                  value.c_str(),
-                  socket.name.c_str());
+          LOG(ERROR) << "Unknown value \"" << value.c_str() << "\" for attribute \""
+                     << socket.name.c_str() << "\"";
         }
         break;
       }
diff --git a/intern/cycles/hydra/file_reader.cpp b/intern/cycles/hydra/file_reader.cpp
index 93de07c0de6..ac9d7bd1e47 100644
--- a/intern/cycles/hydra/file_reader.cpp
+++ b/intern/cycles/hydra/file_reader.cpp
@@ -6,6 +6,7 @@
 #include "hydra/camera.h"
 #include "hydra/render_delegate.h"
 
+#include "util/log.h"
 #include "util/path.h"
 #include "util/unique_ptr.h"
 
@@ -59,7 +60,7 @@ void HdCyclesFileReader::read(Session *session, const char *filepath, const bool
   /* Open Stage. */
   const UsdStageRefPtr stage = UsdStage::Open(filepath);
   if (!stage) {
-    fprintf(stderr, "%s read error\n", filepath);
+    LOG(ERROR) << "USD failed to read " << filepath;
     return;
   }
 
diff --git a/intern/cycles/integrator/denoiser_oidn.cpp b/intern/cycles/integrator/denoiser_oidn.cpp
index 829b0accd63..f0990883b8b 100644
--- a/intern/cycles/integrator/denoiser_oidn.cpp
+++ b/intern/cycles/integrator/denoiser_oidn.cpp
@@ -121,7 +121,7 @@ class OIDNDenoiseContext {
     const char *custom_weight_path = getenv("CYCLES_OIDN_CUSTOM_WEIGHTS");
     if (custom_weight_path) {
       if (!path_read_binary(custom_weight_path, custom_weights)) {
-        fprintf(stderr, "Cycles: Failed to load custom OIDN weights!");
+        LOG(ERROR) << "Failed to load custom OpenImageDenoise weights";
       }
     }
   }
diff --git a/intern/cycles/integrator/denoiser_oidn_gpu.cpp b/intern/cycles/integrator/denoiser_oidn_gpu.cpp
index 92aac3f9cce..32f41735b19 100644
--- a/intern/cycles/integrator/denoiser_oidn_gpu.cpp
+++ b/intern/cycles/integrator/denoiser_oidn_gpu.cpp
@@ -335,7 +335,7 @@ bool OIDNDenoiserGPU::denoise_create_if_needed(DenoiseContext &context)
           oidn_filter_, "weights", custom_weights.data(), custom_weights.size());
     }
     else {
-      fprintf(stderr, "Cycles: Failed to load custom OIDN weights!");
+      LOG(ERROR) << "Failed to load custom OpenImageDenoise weights";
     }
   }
 
diff --git a/intern/cycles/scene/osl.cpp b/intern/cycles/scene/osl.cpp
index e5cf89ba414..37353b136b8 100644
--- a/intern/cycles/scene/osl.cpp
+++ b/intern/cycles/scene/osl.cpp
@@ -567,7 +567,7 @@ const char *OSLManager::shader_load_filepath(string filepath)
   string bytecode;
 
   if (!path_read_text(filepath, bytecode)) {
-    fprintf(stderr, "Cycles shader graph: failed to read file %s\n", filepath.c_str());
+    LOG(ERROR) << "Shader graph: failed to read file " << filepath;
     const OSLShaderInfo info;
     loaded_shaders[bytecode_hash] = info; /* to avoid repeat tries */
     return nullptr;
@@ -588,7 +588,7 @@ const char *OSLManager::shader_load_bytecode(const string &hash, const string &b
   OSLShaderInfo info;
 
   if (!info.query.open_bytecode(bytecode)) {
-    fprintf(stderr, "OSL query error: %s\n", info.query.geterror().c_str());
+    LOG(ERROR) << "OSL query error: " << info.query.geterror();
   }
 
   /* this is a bit weak, but works */
diff --git a/intern/cycles/scene/shader_graph.cpp b/intern/cycles/scene/shader_graph.cpp
index 242cc1b77ff..8eefea34904 100644
--- a/intern/cycles/scene/shader_graph.cpp
+++ b/intern/cycles/scene/shader_graph.cpp
@@ -241,20 +241,16 @@ void ShaderGraph::connect(ShaderOutput *from, ShaderInput *to)
   assert(from && to);
 
   if (to->link) {
-    fprintf(stderr, "Cycles shader graph connect: input already connected.\n");
+    LOG(WARNING) << "Sraph connect: input already connected.";
     return;
   }
 
   if (from->type() != to->type()) {
     /* can't do automatic conversion from closure */
     if (from->type() == SocketType::CLOSURE) {
-      fprintf(stderr,
-              "Cycles shader graph connect: can only connect closure to closure "
-              "(%s.%s to %s.%s).\n",
-              from->parent->name.c_str(),
-              from->name().c_str(),
-              to->parent->name.c_str(),
-              to->name().c_str());
+      LOG(WARNING) << "Shader graph connect: can only connect closure to closure ("
+                   << from->parent->name.c_str() << "." << from->name().c_str() << " to "
+                   << to->parent->name.c_str() << "." << to->name().c_str() << ")";
       return;
     }
 
@@ -721,7 +717,7 @@ void ShaderGraph::break_cycles(ShaderNode *node, vector<bool> &visited, vector<b
       if (on_stack[depnode->id]) {
         /* break cycle */
         disconnect(input);
-        fprintf(stderr, "Cycles shader graph: detected cycle in graph, connection removed.\n");
+        LOG(WARNING) << "Shader graph: detected cycle in graph, connection removed.";
       }
       else if (!visited[depnode->id]) {
         /* visit dependencies */
@@ -1200,7 +1196,7 @@ void ShaderGraph::dump_graph(const char *filename)
   FILE *fd = fopen(filename, "w");
 
   if (fd == nullptr) {
-    printf("Error opening file for dumping the graph: %s\n", filename);
+    LOG(ERROR) << "Error opening file for dumping the graph: " << filename;
     return;
   }
 
diff --git a/intern/cycles/scene/svm.cpp b/intern/cycles/scene/svm.cpp
index 4934b4baeb0..82747dcb503 100644
--- a/intern/cycles/scene/svm.cpp
+++ b/intern/cycles/scene/svm.cpp
@@ -217,9 +217,8 @@ int SVMCompiler::stack_find_offset(const int size)
 
   if (!compile_failed) {
     compile_failed = true;
-    fprintf(stderr,
-            "Cycles: out of SVM stack space, shader \"%s\" too big.\n",
-            current_shader->name.c_str());
+    LOG(ERROR) << "Shader graph: out of SVM stack space, shader \"" << current_shader->name
+               << "\" too big.";
   }
 
   return 0;
diff --git a/intern/cycles/session/denoising.cpp b/intern/cycles/session/denoising.cpp
index 9df5d091c48..8a893c86a7d 100644
--- a/intern/cycles/session/denoising.cpp
+++ b/intern/cycles/session/denoising.cpp
@@ -292,8 +292,6 @@ bool DenoiseTask::exec()
       }
       out += image.num_channels * image.width;
     }
-
-    printf("\n");
   }
 
   return true;
diff --git a/intern/cycles/util/guarded_allocator.h b/intern/cycles/util/guarded_allocator.h
index 21e2c647cc5..0b5566fbbfa 100644
--- a/intern/cycles/util/guarded_allocator.h
+++ b/intern/cycles/util/guarded_allocator.h
@@ -152,7 +152,7 @@ size_t util_guarded_get_mem_peak();
       (func)(__VA_ARGS__); \
     } \
     catch (std::bad_alloc &) { \
-      fprintf(stderr, "Error: run out of memory!\n"); \
+      LOG(ERROR) << "Out of memory"; \
       fflush(stderr); \
       (progress)->set_error("Out of memory"); \
     } \
diff --git a/intern/cycles/util/log.cpp b/intern/cycles/util/log.cpp
index 64c153aee51..8408a9dec03 100644
--- a/intern/cycles/util/log.cpp
+++ b/intern/cycles/util/log.cpp
@@ -14,7 +14,7 @@
 
 CCL_NAMESPACE_BEGIN
 
-LogLevel LOG_LEVEL = DWARNING;
+LogLevel LOG_LEVEL = INFO_IMPORTANT;
 static LogFunction LOG_FUNCTION;
 static double LOG_START_TIME = time_dt();
 
@@ -30,6 +30,7 @@ const char *log_level_to_string(const LogLevel level)
     case WARNING:
     case DWARNING:
       return "WARNING";
+    case INFO_IMPORTANT:
     case INFO:
       return "INFO";
     case WORK:
@@ -59,7 +60,7 @@ LogLevel log_string_to_level(const string &str)
     return WARNING;
   }
   if (str_lower == "info") {
-    return FATAL;
+    return INFO;
   }
   if (str_lower == "work") {
     return WORK;
diff --git a/intern/cycles/util/log.h b/intern/cycles/util/log.h
index db90db04177..a41cb4b87b4 100644
--- a/intern/cycles/util/log.h
+++ b/intern/cycles/util/log.h
@@ -15,16 +15,17 @@ CCL_NAMESPACE_BEGIN
 /* Log Levels */
 
 enum LogLevel {
-  FATAL = 0,    /* Fatal error, application will abort */
-  DFATAL = 1,   /* Fatal error in debug build only */
-  ERROR = 2,    /* Error */
-  DERROR = 3,   /* Error in debug build only */
-  WARNING = 4,  /* Warning */
-  DWARNING = 5, /* Warning in debug build only */
-  INFO = 6,     /* Info about devices, scene contents and features used. */
-  WORK = 7,     /* Work being performed and timing/memory stats about that work. */
-  STATS = 8,    /* Detailed device timing stats. */
-  DEBUG = 9,    /* Verbose debug messages. */
+  FATAL = 0,          /* Fatal error, application will abort */
+  DFATAL = 1,         /* Fatal error in debug build only */
+  ERROR = 2,          /* Error */
+  DERROR = 3,         /* Error in debug build only */
+  WARNING = 4,        /* Warning */
+  DWARNING = 5,       /* Warning in debug build only */
+  INFO_IMPORTANT = 6, /* Important info that is printed by default */
+  INFO = 7,           /* Info about devices, scene contents and features used. */
+  WORK = 8,           /* Work being performed and timing/memory stats about that work. */
+  STATS = 9,          /* Detailed device timing stats. */
+  DEBUG = 10,         /* Verbose debug messages. */
   UNKNOWN = -1,
 };
 
@@ -78,19 +79,16 @@ extern LogLevel LOG_LEVEL;
 #define LOG_STRINGIFY_APPEND(a, b) "" a #b
 #define LOG_STRINGIFY(x) LOG_STRINGIFY_APPEND("", x)
 
+/* Macro to ensure lazy evaluation of both condition and logging text. */
 #ifdef NDEBUG
 #  define LOG_IF(level, condition) \
     if constexpr (level != DFATAL && level != DERROR && level != DWARNING) \
-      if (LIKELY(!(level <= LOG_LEVEL && (condition)))) \
-        ; \
-      else \
-        LogMessage(level, __FILE__ ":" LOG_STRINGIFY(__LINE__), __func__).stream()
+      if (UNLIKELY(level <= LOG_LEVEL && (condition))) \
+    LogMessage(level, __FILE__ ":" LOG_STRINGIFY(__LINE__), __func__).stream()
 #else
 #  define LOG_IF(level, condition) \
-    if (LIKELY(!(level <= LOG_LEVEL && (condition)))) \
-      ; \
-    else \
-      LogMessage(level, __FILE__ ":" LOG_STRINGIFY(__LINE__), __func__).stream()
+    if (UNLIKELY(level <= LOG_LEVEL && (condition))) \
+    LogMessage(level, __FILE__ ":" LOG_STRINGIFY(__LINE__), __func__).stream()
 #endif
 
 /* Log a message at the desired level.
diff --git a/intern/cycles/util/md5.cpp b/intern/cycles/util/md5.cpp
index be389c117f8..acd1a5fbeff 100644
--- a/intern/cycles/util/md5.cpp
+++ b/intern/cycles/util/md5.cpp
@@ -7,6 +7,7 @@
 /* Minor modifications done to remove some code and change style. */
 
 #include "util/md5.h"
+#include "util/log.h"
 #include "util/path.h"
 
 #include <cstdio>
@@ -311,7 +312,7 @@ bool MD5Hash::append_file(const string &filepath)
   FILE *f = path_fopen(filepath, "rb");
 
   if (!f) {
-    fprintf(stderr, "MD5: failed to open file %s\n", filepath.c_str());
+    LOG(ERROR) << "MD5: failed to open file " << filepath;
     return false;
   }