diff --git a/scripts/darkCapture.sh b/scripts/darkCapture.sh
index ffc263b5d..fff5f7b51 100755
--- a/scripts/darkCapture.sh
+++ b/scripts/darkCapture.sh
@@ -1,32 +1,46 @@
 #!/bin/bash
 
 # This file is "source"d into another.
-cd $ALLSKY_HOME
 
-# If we are in darkframe mode, we only save to the dark file
-DARK_MODE=$(jq -r '.darkframe' "$CAMERA_SETTINGS")
-USE_NOTIFICATION_IMAGES=$(jq -r '.notificationimages' "$CAMERA_SETTINGS")
+# ${TEMPERATURE} is passed to us by saveImage.sh, but may be null.
+# If ${TEMPERATURE} is set, use it as the temperature, otherwise read the ${TEMPERATURE_FILE}.
+# If the ${TEMPERATURE_FILE} file doesn't exist, set the temperature to "n/a".
+if [ "${TEMPERATURE}" = "" ]; then
+	TEMPERATURE_FILE="${ALLSKY_HOME}/temperature.txt"
+	if [ -s "${TEMPERATURE_FILE}" ]; then	# -s so we don't use an empty file
+		TEMPERATURE=$(printf "%2.0f" "$(< ${TEMPERATURE_FILE})")
+	else
+		TEMPERATURE="n/a"
+	fi
+fi
 
-# If the temperature file doesn't exist, set a default value
-TEMP=20
+DARK_MODE=$(jq -r '.darkframe' "$CAMERA_SETTINGS")
 if [ "$DARK_MODE" = "1" ] ; then
+	# "${CURRENT_IMAGE}" is the name of the current image we're working on.
+	CURRENT_IMAGE="dark.${EXTENSION}"		# XXXXX in future release this will be set by saveImage.sh
 
-	TEMP_FILE="temperature.txt"
-	if [ -s "$TEMP_FILE" ]; then		# -s so we don't use an empty file
-		TEMP=$(printf "%.0f" "`cat ${TEMP_FILE}`")
+	DARKS_DIR="${ALLSKY_DARKS}"
+	mkdir -p "${DARKS_DIR}"
+	# If the camera doesn't support temperature, we will keep overwriting the file until
+	#	user creates temperature.txt file.
+	if [ "${TEMPERATURE}" = "n/a" ]; then
+		cp "${CURRENT_IMAGE}" "${DARKS_DIR}/dark.${EXTENSION}"
+	else
+		cp "${CURRENT_IMAGE}" "${DARKS_DIR}/${TEMPERATURE}.${EXTENSION}"
 	fi
 
-        mkdir -p darks
-	# To avoid having the websites display a dark frame, when in dark mode
-	# the image file is different.
-	DARK_FRAME="dark.$EXTENSION"
-        cp "$DARK_FRAME" "darks/$TEMP.$EXTENSION"
-
-	# If the user has notification images on, the current images says we're taking dark frames, so don't overwrite.
-	if [ "$USE_NOTIFICATION_IMAGES" = "0" ] ; then
-		# Go ahead and let the web sites see the dark frame.  Not very interesting though...
-        	cp "$DARK_FRAME" "${IMG_PREFIX}${FILENAME}.${EXTENSION}"
+	# If the user has notification images on, the current image says we're taking dark frames,
+	# so don't overwrite it.
+	# xxxx It's possible some people will want to see the dark frame even if notification images
+	# are being used - may need to make it optional to see the dark frame.
+	USE_NOTIFICATION_IMAGES=$(jq -r '.notificationimages' "${CAMERA_SETTINGS}")
+	if [ "${USE_NOTIFICATION_IMAGES}" = "0" ] ; then
+		# Go ahead and let the web sites see the dark frame to see if it's working.
+		cp "${CURRENT_IMAGE}" "${FULL_FILENAME}"
 	fi
 
-        exit 0	# exit so the calling script exits.
+	exit 0	# exit so the calling script exits.
+	
+else	
+	CURRENT_IMAGE="${FULL_FILENAME}"	# Not capturing darks so use standard file name
 fi
diff --git a/scripts/darkSubtract.sh b/scripts/darkSubtract.sh
index 851610f4b..9c626a77b 100755
--- a/scripts/darkSubtract.sh
+++ b/scripts/darkSubtract.sh
@@ -1,42 +1,91 @@
 #!/bin/bash
 
-cd $ALLSKY_HOME
+# This file is "source"d into another.
+# "${CURRENT_IMAGE}" is the name of the current image we're working on.
 
-ME="$(basename "$BASH_ARGV0")"	# Include script name in output so it's easier to find in the log file
+ME="$(basename "${BASH_ARGV0}")"
 
 # Subtract dark frame if there is one defined in config.sh
-# This has to come after executing darkCapture.sh which sets ${TEMP}.
-
-if [ "$DARK_FRAME_SUBTRACTION" = "true" ]; then
-	# Find the closest dark frame temperature wise
-	CLOSEST_TEMP=0
-	DIFF=100
-	for file in darks/*
-	do
-    		if [[ -f $file ]]; then		# example file name for 21 degree dark: "darks/21.jpg".
-        		DARK_TEMP=$(echo $file | awk -F[/.] '{print $2}')
-        		DELTA=$(expr $TEMP - $CLOSEST_TEMP)
-			ABS_DELTA=${DELTA#-}
-
-        		if [ "$ABS_DELTA" -lt "$DIFF"  ]; then
-                		DIFF=$DELTA
-                		CLOSEST_TEMP=$DARK_TEMP
-        		fi
-    		fi
-	done
-
-	PROCESSED_FILE="$FILENAME-processed.$EXTENSION"
-	DARK="darks/$CLOSEST_TEMP.$EXTENSION"
-	if [ -f "$DARK" ]; then
-  	      convert "$FULL_FILENAME" "$DARK" -compose minus_src -composite -type TrueColor "$PROCESSED_FILE"
-	      RET=$?
-	      if [ $RET -ne 0 ]; then
-		      echo "*** $ME: ERROR: 'convert' of '$DARK' failed with RET=$RET"
-		      exit 1
-	      fi
+# This has to come after executing darkCapture.sh which sets ${TEMPERATURE}.
+
+if [ "${DARK_FRAME_SUBTRACTION}" = "true" ]; then
+	# Make sure the input file exists; if not, something major is wrong so exit.
+	if [ "${CURRENT_IMAGE}" = "" ]; then
+		echo "*** ${ME}: ERROR: 'CURRENT_IMAGE' not set; aborting."
+		exit 1
+	fi
+	if [ ! -f "${CURRENT_IMAGE}" ]; then
+		echo "*** ${ME}: ERROR: '${CURRENT_IMAGE}' does not exist; aborting."
+		exit 2
+	fi
+
+	# Make sure we know the current temperature.
+	# If it doesn't exist, warn the user but continue.
+	if [ "${TEMPERATURE}" = "" ]; then
+		echo "*** ${ME}: WARNING: 'TEMPERATURE' not set; continuing without dark subtraction."
+		return
+	fi
+	# Some cameras don't have a sensor temp, so don't attempt dark subtraction for them.
+	[ "${TEMPERATURE}" = "n/a" ] && return
+
+	# First check if we have an exact match.
+	DARKS_DIR="${ALLSKY_DARKS}"
+	DARK="${DARKS_DIR}/${TEMPERATURE}.${EXTENSION}"
+	if [ -s "${DARK}" ]; then
+		CLOSEST_TEMPERATURE="${TEMPERATURE}"
 	else
-		echo "*** $ME: ERROR: No dark frame found for $FULL_FILENAME at TEMP $TEMP." >> log.txt
-		echo "Either take dark frames or turn DARK_FRAME_SUBTRACTION off in config.sh" >> log.txt
-		cp "$FULL_FILENAME" "$PROCESSED_FILE"
+		# Find the closest dark frame temperature wise
+		typeset -i CLOSEST_TEMPERATURE	# don't set yet
+		typeset -i DIFF=100		# any sufficiently high number
+		typeset -i TEMPERATURE=${TEMPERATURE}
+		typeset -i OVERDIFF		# DIFF when dark file temp > ${TEMPERATURE}
+		typeset -i DARK_TEMPERATURE
+
+		# Sort the files by temperature so once we find a file at a higher temperature
+		# than ${TEMPERATURE}, stop, then compare it to the previous file to
+		# determine which is closer to ${TEMPERATURE}.
+		# Need "--general-numeric-sort" in case any files have a leading "-".
+		for file in $(find "${DARKS_DIR}" -maxdepth 1 -iname "*.${EXTENSION}" | sed 's;.*/;;' | sort --general-numeric-sort)
+		do
+			[ "${ALLSKY_DEBUG_LEVEL}" -ge 5 ] && echo "Looking at ${file}"
+			# Example file name for 21 degree dark: "21.jpg".
+			if [ -s "${DARKS_DIR}/${file}" ]; then
+				file=$(basename "./${file}")	# need "./" in case file has "-"
+				# Get name of file (which is the temp) without extension
+				DARK_TEMPERATURE=${file%.*}
+				if [ ${DARK_TEMPERATURE} -gt ${TEMPERATURE} ]; then
+					let OVERDIFF=${DARK_TEMPERATURE}-${TEMPERATURE}
+					if [ ${OVERDIFF} -lt ${DIFF} ]; then
+						CLOSEST_TEMPERATURE=${DARK_TEMPERATURE}
+					fi
+					break
+				fi
+				CLOSEST_TEMPERATURE=${DARK_TEMPERATURE}
+				let DIFF=${TEMPERATURE}-${CLOSEST_TEMPERATURE}
+			else
+				echo "${ME}: INFORMATION: dark file '${DARKS_DIR}/${file}' is zero-length; deleting."
+				rm -f "${DARKS_DIR}/${file}"
+			fi
+		done
+
+		if [ "${CLOSEST_TEMPERATURE}" = "" ]; then
+			echo "*** ${ME}: ERROR: No dark frame found for ${CURRENT_IMAGE} at TEMPERATURE ${TEMPERATURE}."
+			echo "Either take dark frames or turn DARK_FRAME_SUBTRACTION off in config.sh"
+			echo "Continuing without dark subtraction."
+			return
+		fi
+
+		DARK="${DARKS_DIR}/${CLOSEST_TEMPERATURE}.${EXTENSION}"
+	fi
+
+	if [ "${ALLSKY_DEBUG_LEVEL}" -ge 4 ]; then
+		echo "${ME}: Subtracting dark frame '${CLOSEST_TEMPERATURE}.${EXTENSION}' from image with TEMPERATURE=${TEMPERATURE}"
+	fi
+	# Update the current image - don't rename it.
+	convert "${CURRENT_IMAGE}" "${DARK}" -compose minus_src -composite -type TrueColor "${CURRENT_IMAGE}"
+	if [ $? -ne 0 ]; then
+		# Exit since we don't know the state of ${CURRENT_IMAGE}.
+		echo "*** ${ME}: ERROR: 'convert' of '${DARK}' failed"
+		exit 4
 	fi
 fi
diff --git a/scripts/saveImageNight.sh b/scripts/saveImageNight.sh
index 50d5acacd..81da32671 100755
--- a/scripts/saveImageNight.sh
+++ b/scripts/saveImageNight.sh
@@ -34,18 +34,6 @@ if [ $RET -ne 0 ] ; then
 	exit 3
 fi
 
-if [ "$DARK_FRAME_SUBTRACTION" = "true" ] ; then
-	# PROCESSED_FILE should have been created by darkSubtract.sh.  If not, it output an error message.
-	PROCESSED_FILE="$FILENAME-processed.$EXTENSION"
-	# Check in case the user has subtraction set to "true" but has no dark frames.
-	if [[ ! -f "$PROCESSED_FILE" ]]; then
-		echo "${YELLOW}*** $ME: WARNING: Processed image '$PROCESSED_FILE' does not exist; continuing!${NC}"
-	else
-		# Want the name of the final file to alway be the same
-		mv -f "$PROCESSED_FILE" "$IMAGE_TO_USE"
-	fi
-fi
-
 # Resize the image if required
 if [[ $IMG_RESIZE == "true" ]]; then
         convert "$IMAGE_TO_USE" -resize "$IMG_WIDTH"x"$IMG_HEIGHT" "$IMAGE_TO_USE"