diff --git a/app/dmbackup.f90 b/app/dmbackup.f90
index ab1d647..49d4bd6 100644
--- a/app/dmbackup.f90
+++ b/app/dmbackup.f90
@@ -48,7 +48,7 @@ integer function backup(app) result(rc)
         rc = dm_db_open(db, app%database)
 
         if (dm_is_error(rc)) then
-            call dm_error_out(rc, 'failed to open database')
+            call dm_error_out(rc, 'failed to open database ' // app%database)
             return
         end if
 
diff --git a/app/dmbot.f90 b/app/dmbot.f90
index 41721af..edef59d 100644
--- a/app/dmbot.f90
+++ b/app/dmbot.f90
@@ -709,7 +709,7 @@ function message_callback(connection, stanza, user_data) bind(c)
         type = xmpp_stanza_get_type(stanza)
 
         if (type == IM_STANZA_TYPE_ERROR) then
-            call logger%warning('received error message', error=E_IO)
+            call logger%warning('received error stanza', error=E_IO)
             return
         end if
 
diff --git a/app/dmdb.f90 b/app/dmdb.f90
index df9f1e8..4fad611 100644
--- a/app/dmdb.f90
+++ b/app/dmdb.f90
@@ -47,12 +47,12 @@ program dmdb
 
     ! Initialise logger.
     logger => dm_logger_get_default()
-    call logger%configure(name    = app%logger, &
-                          node_id = app%node_id, &
-                          source  = app%name, &
-                          debug   = app%debug, &
-                          ipc     = (len_trim(app%logger) > 0), &
-                          verbose = app%verbose)
+    call logger%configure(name    = app%logger,                 & ! Name of logger process.
+                          node_id = app%node_id,                & ! Node id.
+                          source  = app%name,                   & ! Log source.
+                          debug   = app%debug,                  & ! Forward debug messages via IPC.
+                          ipc     = (len_trim(app%logger) > 0), & ! Enable IPC.
+                          verbose = app%verbose)                  ! Print logs to standard error.
 
     init_block: block
         ! Open SQLite database.
@@ -64,10 +64,10 @@ program dmdb
         end if
 
         ! Open observation message queue for reading.
-        rc = dm_mqueue_open(mqueue = mqueue, &
-                            type   = TYPE_OBSERV, &
-                            name   = app%name, &
-                            access = MQUEUE_RDONLY)
+        rc = dm_mqueue_open(mqueue = mqueue,      & ! Message queue type.
+                            type   = TYPE_OBSERV, & ! Observation type.
+                            name   = app%name,    & ! Name of message queue.
+                            access = MQUEUE_RDONLY) ! Read-only access.
 
         if (dm_is_error(rc)) then
             call logger%error('failed to open mqueue /' // trim(app%name) // ': ' // &
diff --git a/app/dmfs.f90 b/app/dmfs.f90
index 55e9c51..d2cb80d 100644
--- a/app/dmfs.f90
+++ b/app/dmfs.f90
@@ -49,12 +49,12 @@ program dmfs
 
     ! Initialise logger.
     logger => dm_logger_get_default()
-    call logger%configure(name    = app%logger, &
-                          node_id = app%node_id, &
-                          source  = app%name, &
-                          debug   = app%debug, &
-                          ipc     = (len_trim(app%logger) > 0), &
-                          verbose = app%verbose)
+    call logger%configure(name    = app%logger,                 & ! Name of logger process.
+                          node_id = app%node_id,                & ! Node id.
+                          source  = app%name,                   & ! Log source.
+                          debug   = app%debug,                  & ! Forward debug messages via IPC.
+                          ipc     = (len_trim(app%logger) > 0), & ! Enable IPC.
+                          verbose = app%verbose)                  ! Print logs to standard error.
 
     ! Run main loop.
     call dm_signal_register(signal_callback)
diff --git a/app/dmgrc.f90 b/app/dmgrc.f90
index 68c1e02..4e82400 100644
--- a/app/dmgrc.f90
+++ b/app/dmgrc.f90
@@ -48,19 +48,19 @@ program dmgrc
 
     ! Initialise logger.
     logger => dm_logger_get_default()
-    call logger%configure(name    = app%logger, &
-                          node_id = app%node_id, &
-                          source  = app%name, &
-                          debug   = app%debug, &
-                          ipc     = (len_trim(app%logger) > 0), &
-                          verbose = app%verbose)
+    call logger%configure(name    = app%logger,                 & ! Name of logger process.
+                          node_id = app%node_id,                & ! Node id.
+                          source  = app%name,                   & ! Log source.
+                          debug   = app%debug,                  & ! Forward debug messages via IPC.
+                          ipc     = (len_trim(app%logger) > 0), & ! Enable IPC.
+                          verbose = app%verbose)                  ! Print logs to standard error.
 
     init_block: block
         ! Open observation message queue for reading.
-        rc = dm_mqueue_open(mqueue = mqueue, &
-                            type   = TYPE_OBSERV, &
-                            name   = app%name, &
-                            access = MQUEUE_RDONLY)
+        rc = dm_mqueue_open(mqueue = mqueue,      & ! Message queue type.
+                            type   = TYPE_OBSERV, & ! Observation type.
+                            name   = app%name,    & ! Name of message queue.
+                            access = MQUEUE_RDONLY) ! Read-only access.
 
         if (dm_is_error(rc)) then
             call dm_error_out(rc, 'failed to open mqueue /' // trim(app%name) // ': ' // dm_system_error_message())
diff --git a/app/dmimport.f90 b/app/dmimport.f90
index ed29753..f528528 100644
--- a/app/dmimport.f90
+++ b/app/dmimport.f90
@@ -90,16 +90,11 @@ integer function import(app) result(rc)
 
                 ! Check for appropriate database table.
                 select case (app%type)
-                    case (TYPE_NODE)
-                        has = dm_db_has_table(db, SQL_TABLE_NODES)
-                    case (TYPE_SENSOR)
-                        has = dm_db_has_table(db, SQL_TABLE_SENSORS)
-                    case (TYPE_TARGET)
-                        has = dm_db_has_table(db, SQL_TABLE_TARGETS)
-                    case (TYPE_OBSERV)
-                        has = dm_db_has_table(db, SQL_TABLE_OBSERVS)
-                    case (TYPE_LOG)
-                        has = dm_db_has_table(db, SQL_TABLE_LOGS)
+                    case (TYPE_NODE);   has = dm_db_has_table(db, SQL_TABLE_NODES)
+                    case (TYPE_SENSOR); has = dm_db_has_table(db, SQL_TABLE_SENSORS)
+                    case (TYPE_TARGET); has = dm_db_has_table(db, SQL_TABLE_TARGETS)
+                    case (TYPE_OBSERV); has = dm_db_has_table(db, SQL_TABLE_OBSERVS)
+                    case (TYPE_LOG);    has = dm_db_has_table(db, SQL_TABLE_LOGS)
                 end select
 
                 if (.not. has) then
@@ -131,16 +126,11 @@ integer function import(app) result(rc)
 
                 ! Read record from file.
                 select case (app%type)
-                    case (TYPE_NODE)
-                        rc = dm_csv_read(node, unit, app%separator, app%quote)
-                    case (TYPE_SENSOR)
-                        rc = dm_csv_read(sensor, unit, app%separator, app%quote)
-                    case (TYPE_TARGET)
-                        rc = dm_csv_read(target, unit, app%separator, app%quote)
-                    case (TYPE_OBSERV)
-                        rc = dm_csv_read(observ, unit, app%separator, app%quote)
-                    case (TYPE_LOG)
-                        rc = dm_csv_read(log, unit, app%separator, app%quote)
+                    case (TYPE_NODE);   rc = dm_csv_read(node,   unit, app%separator, app%quote)
+                    case (TYPE_SENSOR); rc = dm_csv_read(sensor, unit, app%separator, app%quote)
+                    case (TYPE_TARGET); rc = dm_csv_read(target, unit, app%separator, app%quote)
+                    case (TYPE_OBSERV); rc = dm_csv_read(observ, unit, app%separator, app%quote)
+                    case (TYPE_LOG);    rc = dm_csv_read(log,    unit, app%separator, app%quote)
                 end select
 
                 ! Ignore comments and empty rows.
@@ -161,16 +151,11 @@ integer function import(app) result(rc)
                 ! Validate record but skip database insert on dry run.
                 if (app%dry) then
                     select case (app%type)
-                        case (TYPE_NODE)
-                            valid = dm_node_is_valid(node)
-                        case (TYPE_SENSOR)
-                            valid = dm_sensor_is_valid(sensor)
-                        case (TYPE_TARGET)
-                            valid = dm_target_is_valid(target)
-                        case (TYPE_OBSERV)
-                            valid = dm_observ_is_valid(observ)
-                        case (TYPE_LOG)
-                            valid = dm_log_is_valid(log)
+                        case (TYPE_NODE);   valid = dm_node_is_valid(node)
+                        case (TYPE_SENSOR); valid = dm_sensor_is_valid(sensor)
+                        case (TYPE_TARGET); valid = dm_target_is_valid(target)
+                        case (TYPE_OBSERV); valid = dm_observ_is_valid(observ)
+                        case (TYPE_LOG);    valid = dm_log_is_valid(log)
                     end select
 
                     if (.not. valid) then
@@ -184,16 +169,11 @@ integer function import(app) result(rc)
 
                 ! Validate and insert record.
                 select case (app%type)
-                    case (TYPE_NODE)
-                        rc = dm_db_insert(db, node)
-                    case (TYPE_SENSOR)
-                        rc = dm_db_insert(db, sensor)
-                    case (TYPE_TARGET)
-                        rc = dm_db_insert(db, target)
-                    case (TYPE_OBSERV)
-                        rc = dm_db_insert(db, observ)
-                    case (TYPE_LOG)
-                        rc = dm_db_insert(db, log)
+                    case (TYPE_NODE);   rc = dm_db_insert(db, node)
+                    case (TYPE_SENSOR); rc = dm_db_insert(db, sensor)
+                    case (TYPE_TARGET); rc = dm_db_insert(db, target)
+                    case (TYPE_OBSERV); rc = dm_db_insert(db, observ)
+                    case (TYPE_LOG);    rc = dm_db_insert(db, log)
                 end select
 
                 ! Handle database result.
diff --git a/app/dmlog.f90 b/app/dmlog.f90
index 3ce44f3..d2678e7 100644
--- a/app/dmlog.f90
+++ b/app/dmlog.f90
@@ -58,7 +58,7 @@ integer function read_args(app, log) result(rc)
             arg_type('target',  short='T', type=ARG_TYPE_ID),      & ! -T, --target <id>
             arg_type('observ',  short='O', type=ARG_TYPE_UUID),    & ! -O, --observ <uuid>
             arg_type('source',  short='Z', type=ARG_TYPE_ID,     max_len=LOG_SOURCE_LEN), & ! -Z, --source <id>
-            arg_type('message', short='m', type=ARG_TYPE_STRING, max_len=LOG_MESSAGE_LEN, required=.true.) &  ! -m, --message <string>
+            arg_type('message', short='m', type=ARG_TYPE_STRING, max_len=LOG_MESSAGE_LEN, required=.true.) & ! -m, --message <string>
         ]
 
         ! Read all command-line arguments.
diff --git a/app/dmlogger.f90 b/app/dmlogger.f90
index 1fcf64a..b2c7788 100644
--- a/app/dmlogger.f90
+++ b/app/dmlogger.f90
@@ -11,20 +11,20 @@ program dmlogger
     character(len=*), parameter :: APP_NAME  = 'dmlogger'
     integer,          parameter :: APP_MAJOR = 0
     integer,          parameter :: APP_MINOR = 9
-    integer,          parameter :: APP_PATCH = 2
+    integer,          parameter :: APP_PATCH = 3
 
     integer, parameter :: APP_DB_NSTEPS  = 500                !! Number of steps before database is optimised.
     integer, parameter :: APP_DB_TIMEOUT = DB_TIMEOUT_DEFAULT !! SQLite 3 busy timeout in mseconds.
 
     type :: app_type
         !! Application settings.
-        character(len=ID_LEN)        :: name     = APP_NAME   !! Name of logger instance and POSIX semaphore.
-        character(len=FILE_PATH_LEN) :: config   = ' '        !! Path to configuration file.
-        character(len=FILE_PATH_LEN) :: database = ' '        !! Path to SQLite database file.
-        character(len=NODE_ID_LEN)   :: node_id  = ' '        !! Node id.
-        integer                      :: minlevel = LL_WARNING !! Minimum level for a log to be stored in the database.
-        logical                      :: ipc      = .false.    !! Use POSIX semaphore for process synchronisation.
-        logical                      :: verbose  = .false.    !! Print debug messages to stderr.
+        character(len=ID_LEN)        :: name      = APP_NAME !! Name of logger instance and POSIX semaphore.
+        character(len=FILE_PATH_LEN) :: config    = ' '      !! Path to configuration file.
+        character(len=FILE_PATH_LEN) :: database  = ' '      !! Path to SQLite database file.
+        character(len=NODE_ID_LEN)   :: node_id   = ' '      !! Node id.
+        integer                      :: min_level = LL_INFO  !! Minimum level for a log to be stored in the database.
+        logical                      :: ipc       = .false.  !! Use POSIX semaphore for process synchronisation.
+        logical                      :: verbose   = .false.  !! Print debug messages to stderr.
     end type app_type
 
     class(logger_class), pointer :: logger ! Logger object.
@@ -45,10 +45,10 @@ program dmlogger
     init_block: block
         ! Initialise logger.
         logger => dm_logger_get_default()
-        call logger%configure(name    = app%name, &    ! Name of global logger.
+        call logger%configure(name    = app%name,    & ! Name of global logger.
                               node_id = app%node_id, & ! Sensor node id.
-                              source  = app%name, &    ! Application name.
-                              ipc     = .false., &     ! Don't send logs via IPC.
+                              source  = app%name,    & ! Application name.
+                              ipc     = .false.,     & ! Don't send logs via IPC.
                               verbose = app%verbose)   ! Prints logs to terminal.
 
         ! Open SQLite database.
@@ -60,10 +60,10 @@ program dmlogger
         end if
 
         ! Open log message queue for reading.
-        rc = dm_mqueue_open(mqueue = mqueue, &
-                            type   = TYPE_LOG, &
-                            name   = app%name, &
-                            access = MQUEUE_RDONLY)
+        rc = dm_mqueue_open(mqueue = mqueue,   &    ! Message queue type.
+                            type   = TYPE_LOG, &    ! Log type.
+                            name   = app%name, &    ! Name of message queue.
+                            access = MQUEUE_RDONLY) ! Read-only access.
 
         if (dm_is_error(rc)) then
             call logger%error('failed to open mqueue /' // trim(app%name) // ': ' // &
@@ -121,7 +121,7 @@ integer function read_args(app) result(rc)
         ! Overwrite settings.
         call dm_arg_get(args(3), app%database)
         call dm_arg_get(args(4), app%node_id)
-        call dm_arg_get(args(5), app%minlevel)
+        call dm_arg_get(args(5), app%min_level)
         call dm_arg_get(args(6), app%ipc)
         call dm_arg_get(args(7), app%verbose)
 
@@ -146,7 +146,7 @@ integer function read_args(app) result(rc)
             return
         end if
 
-        if (.not. dm_log_level_is_valid(app%minlevel)) then
+        if (.not. dm_log_level_is_valid(app%min_level)) then
             call dm_error_out(rc, 'invalid log level')
             return
         end if
@@ -167,7 +167,7 @@ integer function read_config(app) result(rc)
         if (dm_is_ok(rc)) then
             call dm_config_get(config, 'database', app%database)
             call dm_config_get(config, 'node',     app%node_id)
-            call dm_config_get(config, 'minlevel', app%minlevel)
+            call dm_config_get(config, 'minlevel', app%min_level)
             call dm_config_get(config, 'ipc',      app%ipc)
             call dm_config_get(config, 'verbose',  app%verbose)
         end if
@@ -211,7 +211,7 @@ subroutine run(app, db, mqueue, sem)
 
         call logger%info('started ' // APP_NAME)
         call logger%debug('waiting for log on mqueue /' // trim(app%name) // ' (minimum log level is ' // &
-                          trim(LOG_LEVEL_NAMES(app%minlevel)) // ')')
+                          trim(LOG_LEVEL_NAMES(app%min_level)) // ')')
         ipc_loop: do
             ! Blocking read from POSIX message queue.
             rc = dm_mqueue_read(mqueue, log)
@@ -229,7 +229,7 @@ subroutine run(app, db, mqueue, sem)
             if (app%verbose) call logger%out(log)
 
             ! Skip if log level is lower than minimum level.
-            if (log%level < app%minlevel) cycle ipc_loop
+            if (log%level < app%min_level) cycle ipc_loop
 
             ! Skip if log already exists.
             if (dm_db_has_log(db, log%id)) then
diff --git a/app/dmlua.f90 b/app/dmlua.f90
index 37745b0..8a49ac1 100644
--- a/app/dmlua.f90
+++ b/app/dmlua.f90
@@ -45,12 +45,12 @@ program dmlua
 
     ! Initialise logger.
     logger => dm_logger_get_default()
-    call logger%configure(name    = app%logger, &
-                          node_id = app%node_id, &
-                          source  = app%name, &
-                          debug   = app%debug, &
-                          ipc     = (len_trim(app%logger) > 0), &
-                          verbose = app%verbose)
+    call logger%configure(name    = app%logger,                 & ! Name of logger process.
+                          node_id = app%node_id,                & ! Node id.
+                          source  = app%name,                   & ! Log source.
+                          debug   = app%debug,                  & ! Forward debug messages via IPC.
+                          ipc     = (len_trim(app%logger) > 0), & ! Enable IPC.
+                          verbose = app%verbose)                  ! Print logs to standard error.
 
     init_block: block
         ! Initialise Lua interpreter.
@@ -81,15 +81,15 @@ program dmlua
         rc = dm_lua_open(lua, app%script, eval=.true.)
 
         if (dm_is_error(rc)) then
-            call logger%error('failed to load Lua script', error=rc)
+            call logger%error('failed to load Lua script ' // app%script, error=rc)
             exit init_block
         end if
 
         ! Open observation message queue for reading.
-        rc = dm_mqueue_open(mqueue = mqueue, &
-                            type   = TYPE_OBSERV, &
-                            name   = app%name, &
-                            access = MQUEUE_RDONLY)
+        rc = dm_mqueue_open(mqueue = mqueue,      & ! Message queue type.
+                            type   = TYPE_OBSERV, & ! Observation type.
+                            name   = app%name,    & ! Name of message queue.
+                            access = MQUEUE_RDONLY) ! Read-only access.
 
         if (dm_is_error(rc)) then
             call logger%error('failed to open mqueue /' // trim(app%name) // ': ' // &
diff --git a/app/dmpipe.f90 b/app/dmpipe.f90
index 76b3a68..b549c90 100644
--- a/app/dmpipe.f90
+++ b/app/dmpipe.f90
@@ -52,12 +52,12 @@ program dmpipe
 
     ! Initialise logger.
     logger => dm_logger_get_default()
-    call logger%configure(name    = app%logger, &
-                          node_id = app%node_id, &
-                          source  = app%name, &
-                          debug   = app%debug, &
-                          ipc     = (len_trim(app%logger) > 0), &
-                          verbose = app%verbose)
+    call logger%configure(name    = app%logger,                 & ! Name of logger process.
+                          node_id = app%node_id,                & ! Node id.
+                          source  = app%name,                   & ! Log source.
+                          debug   = app%debug,                  & ! Forward debug messages via IPC.
+                          ipc     = (len_trim(app%logger) > 0), & ! Enable IPC.
+                          verbose = app%verbose)                  ! Print logs to standard error.
 
     ! Run main loop.
     call dm_signal_register(signal_callback)
diff --git a/app/dmrecv.f90 b/app/dmrecv.f90
index 32bf24c..ac9308c 100644
--- a/app/dmrecv.f90
+++ b/app/dmrecv.f90
@@ -62,19 +62,19 @@ program dmrecv
 
     ! Initialise logger.
     logger => dm_logger_get_default()
-    call logger%configure(name    = app%logger, &
-                          node_id = app%node_id, &
-                          source  = app%name, &
-                          debug   = app%debug, &
-                          ipc     = (len_trim(app%logger) > 0), &
-                          verbose = app%verbose)
+    call logger%configure(name    = app%logger,                 & ! Name of logger process.
+                          node_id = app%node_id,                & ! Node id.
+                          source  = app%name,                   & ! Log source.
+                          debug   = app%debug,                  & ! Forward debug messages via IPC.
+                          ipc     = (len_trim(app%logger) > 0), & ! Enable IPC.
+                          verbose = app%verbose)                  ! Print logs to standard error.
 
     init_block: block
         ! Open log message queue for reading.
-        rc = dm_mqueue_open(mqueue = mqueue, &
-                            type   = app%type, &
-                            name   = app%name, &
-                            access = MQUEUE_RDONLY)
+        rc = dm_mqueue_open(mqueue = mqueue,   &    ! Message queue type.
+                            type   = app%type, &    ! Observation or log type.
+                            name   = app%name, &    ! Name of message queue.
+                            access = MQUEUE_RDONLY) ! Read-only access.
 
         if (dm_is_error(rc)) then
             call logger%error('failed to open mqueue /' // app%name, error=rc)
diff --git a/app/dmsend.f90 b/app/dmsend.f90
index e5d394d..c82aa04 100644
--- a/app/dmsend.f90
+++ b/app/dmsend.f90
@@ -46,12 +46,12 @@ program dmsend
 
     ! Initialise logger.
     logger => dm_logger_get_default()
-    call logger%configure(name    = app%logger, &
-                          node_id = app%node_id, &
-                          source  = app%name, &
-                          debug   = app%debug, &
-                          ipc     = (len_trim(app%logger) > 0), &
-                          verbose = app%verbose)
+    call logger%configure(name    = app%logger,                 & ! Name of logger process.
+                          node_id = app%node_id,                & ! Node id.
+                          source  = app%name,                   & ! Log source.
+                          debug   = app%debug,                  & ! Forward debug messages via IPC.
+                          ipc     = (len_trim(app%logger) > 0), & ! Enable IPC.
+                          verbose = app%verbose)                  ! Print logs to standard error.
 
     ! Read and send data.
     rc = run(app)
@@ -192,10 +192,10 @@ integer function run(app) result(rc)
         ! Open message queue of receiver for writing.
         if (.not. app%forward) then
             call logger%debug('opening mqueue /' // app%receiver)
-            rc = dm_mqueue_open(mqueue   = mqueue, &
-                                type     = app%type, &
-                                name     = app%receiver, &
-                                access   = MQUEUE_WRONLY, &
+            rc = dm_mqueue_open(mqueue   = mqueue,        & ! Message queue type.
+                                type     = app%type,      & ! Observation or log type.
+                                name     = app%receiver,  & ! Name of message queue.
+                                access   = MQUEUE_WRONLY, & ! Write-only access.
                                 blocking = .true.)
 
             if (dm_is_error(rc)) then
diff --git a/src/dm_camera.f90 b/src/dm_camera.f90
index abe0120..f927a4c 100644
--- a/src/dm_camera.f90
+++ b/src/dm_camera.f90
@@ -69,7 +69,7 @@ module dm_camera
 
     type, public :: camera_type
         !! Camera settings type.
-        character(len=FILE_PATH_LEN) :: input  = ' '                !! Input device path (`/dev/video0` or `rtsp://10.0.0.1`).
+        character(len=FILE_PATH_LEN) :: input  = ' '                !! Input device path (`/dev/video0` or `rtsp://10.0.0.1/`).
         integer                      :: device = CAMERA_DEVICE_NONE !! Input device.
         integer                      :: width  = 0                  !! Camera stream width in pixels (optional).
         integer                      :: height = 0                  !! Camera stream height in pixels (optional).
@@ -109,8 +109,11 @@ integer function dm_camera_capture(camera, output, command) result(rc)
             if (len_trim(camera%input) == 0 .or. len_trim(output) == 0) exit io_block
 
             rc = E_INVALID
-            if (.not. dm_camera_device_is_valid(camera%device)) return
-            if (camera%device == CAMERA_DEVICE_RTSP .and. .not. dm_string_starts_with(camera%input, 'rtsp://')) exit io_block
+            if (.not. dm_camera_device_is_valid(camera%device)) exit io_block
+
+            if (camera%device == CAMERA_DEVICE_RTSP) then
+                if (.not. dm_string_starts_with(camera%input, 'rtsp://')) exit io_block
+            end if
 
             rc = E_IO
             call camera_prepare_capture(command_, camera, output)
diff --git a/src/dm_gm.f90 b/src/dm_gm.f90
index c5c0275..77907f2 100644
--- a/src/dm_gm.f90
+++ b/src/dm_gm.f90
@@ -105,17 +105,11 @@ module dm_gm
     character(len=*), parameter, public :: GM_COLOR_GHOST_WHITE             = 'ghostwhite'
     character(len=*), parameter, public :: GM_COLOR_GOLD                    = 'gold'
     character(len=*), parameter, public :: GM_COLOR_GOLDE_NROD              = 'goldenrod'
+    character(len=*), parameter, public :: GM_COLOR_GRAY                    = 'gray'
     character(len=*), parameter, public :: GM_COLOR_GRAY0                   = 'gray0'
     character(len=*), parameter, public :: GM_COLOR_GRAY1                   = 'gray1'
-    character(len=*), parameter, public :: GM_COLOR_GRAY2                   = 'gray2'
-    character(len=*), parameter, public :: GM_COLOR_GRAY3                   = 'gray3'
-    character(len=*), parameter, public :: GM_COLOR_GRAY4                   = 'gray4'
-    character(len=*), parameter, public :: GM_COLOR_GRAY5                   = 'gray5'
-    character(len=*), parameter, public :: GM_COLOR_GRAY6                   = 'gray6'
-    character(len=*), parameter, public :: GM_COLOR_GRAY7                   = 'gray7'
-    character(len=*), parameter, public :: GM_COLOR_GRAY8                   = 'gray8'
-    character(len=*), parameter, public :: GM_COLOR_GRAY9                   = 'gray9'
     character(len=*), parameter, public :: GM_COLOR_GRAY10                  = 'gray10'
+    character(len=*), parameter, public :: GM_COLOR_GRAY100                 = 'gray100'
     character(len=*), parameter, public :: GM_COLOR_GRAY11                  = 'gray11'
     character(len=*), parameter, public :: GM_COLOR_GRAY12                  = 'gray12'
     character(len=*), parameter, public :: GM_COLOR_GRAY13                  = 'gray13'
@@ -125,6 +119,7 @@ module dm_gm
     character(len=*), parameter, public :: GM_COLOR_GRAY17                  = 'gray17'
     character(len=*), parameter, public :: GM_COLOR_GRAY18                  = 'gray18'
     character(len=*), parameter, public :: GM_COLOR_GRAY19                  = 'gray19'
+    character(len=*), parameter, public :: GM_COLOR_GRAY2                   = 'gray2'
     character(len=*), parameter, public :: GM_COLOR_GRAY20                  = 'gray20'
     character(len=*), parameter, public :: GM_COLOR_GRAY21                  = 'gray21'
     character(len=*), parameter, public :: GM_COLOR_GRAY22                  = 'gray22'
@@ -135,6 +130,7 @@ module dm_gm
     character(len=*), parameter, public :: GM_COLOR_GRAY27                  = 'gray27'
     character(len=*), parameter, public :: GM_COLOR_GRAY28                  = 'gray28'
     character(len=*), parameter, public :: GM_COLOR_GRAY29                  = 'gray29'
+    character(len=*), parameter, public :: GM_COLOR_GRAY3                   = 'gray3'
     character(len=*), parameter, public :: GM_COLOR_GRAY30                  = 'gray30'
     character(len=*), parameter, public :: GM_COLOR_GRAY31                  = 'gray31'
     character(len=*), parameter, public :: GM_COLOR_GRAY32                  = 'gray32'
@@ -145,6 +141,7 @@ module dm_gm
     character(len=*), parameter, public :: GM_COLOR_GRAY37                  = 'gray37'
     character(len=*), parameter, public :: GM_COLOR_GRAY38                  = 'gray38'
     character(len=*), parameter, public :: GM_COLOR_GRAY39                  = 'gray39'
+    character(len=*), parameter, public :: GM_COLOR_GRAY4                   = 'gray4'
     character(len=*), parameter, public :: GM_COLOR_GRAY40                  = 'gray40'
     character(len=*), parameter, public :: GM_COLOR_GRAY41                  = 'gray41'
     character(len=*), parameter, public :: GM_COLOR_GRAY42                  = 'gray42'
@@ -155,6 +152,7 @@ module dm_gm
     character(len=*), parameter, public :: GM_COLOR_GRAY47                  = 'gray47'
     character(len=*), parameter, public :: GM_COLOR_GRAY48                  = 'gray48'
     character(len=*), parameter, public :: GM_COLOR_GRAY49                  = 'gray49'
+    character(len=*), parameter, public :: GM_COLOR_GRAY5                   = 'gray5'
     character(len=*), parameter, public :: GM_COLOR_GRAY50                  = 'gray50'
     character(len=*), parameter, public :: GM_COLOR_GRAY51                  = 'gray51'
     character(len=*), parameter, public :: GM_COLOR_GRAY52                  = 'gray52'
@@ -165,6 +163,7 @@ module dm_gm
     character(len=*), parameter, public :: GM_COLOR_GRAY57                  = 'gray57'
     character(len=*), parameter, public :: GM_COLOR_GRAY58                  = 'gray58'
     character(len=*), parameter, public :: GM_COLOR_GRAY59                  = 'gray59'
+    character(len=*), parameter, public :: GM_COLOR_GRAY6                   = 'gray6'
     character(len=*), parameter, public :: GM_COLOR_GRAY60                  = 'gray60'
     character(len=*), parameter, public :: GM_COLOR_GRAY61                  = 'gray61'
     character(len=*), parameter, public :: GM_COLOR_GRAY62                  = 'gray62'
@@ -175,6 +174,7 @@ module dm_gm
     character(len=*), parameter, public :: GM_COLOR_GRAY67                  = 'gray67'
     character(len=*), parameter, public :: GM_COLOR_GRAY68                  = 'gray68'
     character(len=*), parameter, public :: GM_COLOR_GRAY69                  = 'gray69'
+    character(len=*), parameter, public :: GM_COLOR_GRAY7                   = 'gray7'
     character(len=*), parameter, public :: GM_COLOR_GRAY70                  = 'gray70'
     character(len=*), parameter, public :: GM_COLOR_GRAY71                  = 'gray71'
     character(len=*), parameter, public :: GM_COLOR_GRAY72                  = 'gray72'
@@ -185,6 +185,7 @@ module dm_gm
     character(len=*), parameter, public :: GM_COLOR_GRAY77                  = 'gray77'
     character(len=*), parameter, public :: GM_COLOR_GRAY78                  = 'gray78'
     character(len=*), parameter, public :: GM_COLOR_GRAY79                  = 'gray79'
+    character(len=*), parameter, public :: GM_COLOR_GRAY8                   = 'gray8'
     character(len=*), parameter, public :: GM_COLOR_GRAY80                  = 'gray80'
     character(len=*), parameter, public :: GM_COLOR_GRAY81                  = 'gray81'
     character(len=*), parameter, public :: GM_COLOR_GRAY82                  = 'gray82'
@@ -195,6 +196,7 @@ module dm_gm
     character(len=*), parameter, public :: GM_COLOR_GRAY87                  = 'gray87'
     character(len=*), parameter, public :: GM_COLOR_GRAY88                  = 'gray88'
     character(len=*), parameter, public :: GM_COLOR_GRAY89                  = 'gray89'
+    character(len=*), parameter, public :: GM_COLOR_GRAY9                   = 'gray9'
     character(len=*), parameter, public :: GM_COLOR_GRAY90                  = 'gray90'
     character(len=*), parameter, public :: GM_COLOR_GRAY91                  = 'gray91'
     character(len=*), parameter, public :: GM_COLOR_GRAY92                  = 'gray92'
@@ -205,8 +207,6 @@ module dm_gm
     character(len=*), parameter, public :: GM_COLOR_GRAY97                  = 'gray97'
     character(len=*), parameter, public :: GM_COLOR_GRAY98                  = 'gray98'
     character(len=*), parameter, public :: GM_COLOR_GRAY99                  = 'gray99'
-    character(len=*), parameter, public :: GM_COLOR_GRAY100                 = 'gray100'
-    character(len=*), parameter, public :: GM_COLOR_GRAY                    = 'gray'
     character(len=*), parameter, public :: GM_COLOR_GREEN                   = 'green'
     character(len=*), parameter, public :: GM_COLOR_GREEN_YELLOW            = 'greenyellow'
     character(len=*), parameter, public :: GM_COLOR_GREY                    = 'grey'
@@ -574,7 +574,7 @@ subroutine gm_prepare_add_text_box(command, path, text, text_box)
         character(len=*),              intent(in)           :: text     !! Text to add.
         type(gm_text_box_type),        intent(in), optional :: text_box !! Image text box type.
 
-        character(len=32)         :: point_size
+        character(len=32)      :: point_size
         type(gm_text_box_type) :: box
 
         if (present(text_box)) box = text_box