ok

code/game/atoms.dm

@@ -444,10 +444,10 @@
 		return
 	var/list/blood_dna = list()
 	if(dna)
-		blood_dna["color"] = list(dna.species.exotic_blood_color) //so when combined, the list grows with the number of colors
+		blood_dna["color"] = dna.species.exotic_blood_color //so when combined, the list grows with the number of colors
 		blood_dna[dna.unique_enzymes] = dna.blood_type
 	else
-		blood_dna["color"] = list(BLOOD_COLOR_HUMAN)
+		blood_dna["color"] = BLOOD_COLOR_HUMAN
 		blood_dna["UNKNOWN DNA"] = "X*"
 	return blood_dna
 
@@ -461,25 +461,35 @@
 	if(!new_blood_dna)
 		return FALSE
 	LAZYINITLIST(blood_DNA)	//if our list of DNA doesn't exist yet, initialise it.
-	LAZYINITLIST(blood_DNA["color"])
 	var/old_length = blood_DNA.len
 	blood_DNA |= new_blood_dna
-	blood_DNA["color"] += new_blood_dna["color"]
+	var/changed = FALSE
+	if(!blood_DNA["color"])
+		blood_DNA["color"] = new_blood_dna["color"]
+		changed = TRUE
+	else
+		var/old = blood_DNA["color"]
+		blood_DNA["color"] = BlendRGB(blood_DNA["color"], new_blood_dna["color"])
+		changed = old != blood_DNA["color"]
 	if(blood_DNA.len == old_length)
 		return FALSE
-	return TRUE
+	return changed
 
 //to add blood dna info to the object's blood_DNA list
 /atom/proc/transfer_blood_dna(list/blood_dna, list/datum/disease/diseases)
 	LAZYINITLIST(blood_DNA)
-	LAZYINITLIST(blood_dna["color"])
 
 	var/old_length = blood_DNA.len
 	blood_DNA |= blood_dna
 	if(blood_DNA.len > old_length)
-		blood_DNA["color"] += blood_dna["color"]
-		return TRUE
+		. = TRUE
 		//some new blood DNA was added
+		if(!blood_dna["color"])
+			return
+		if(!blood_DNA["color"])
+			blood_DNA["color"] = blood_dna["color"]
+		else
+			blood_DNA["color"] = BlendRGB(blood_DNA["color"], blood_dna["color"])
 
 //to add blood from a mob onto something, and transfer their dna info
 /atom/proc/add_mob_blood(mob/living/M)
@@ -548,27 +558,7 @@
 	return TRUE
 
 /atom/proc/blood_DNA_to_color()
-	var/list/colors = list()//first we make a list of all bloodtypes present
-	for(var/blood_color in blood_DNA["color"])
-		if(colors[blood_color])
-			colors[blood_color]++
-		else
-			colors[blood_color] = 1
-
-	var/final_rgb = BLOOD_COLOR_HUMAN	//a default so we don't have white blood graphics if something messed up
-	if(colors.len)
-		var/sum = 0 //this is all shitcode, but it works; trust me
-		final_rgb = colors[1]
-		sum = colors[colors[1]]
-		if(colors.len > 1)
-			var/i = 2
-			while(i <= colors.len)
-				var/tmp = colors[colors[i]]
-				final_rgb = BlendRGB(final_rgb, colors[i], tmp/(tmp+sum))
-				sum += tmp
-				i++
-
-	return final_rgb
+	return (blood_DNA && blood_DNA["color"]) || BLOOD_COLOR_HUMAN
 
 /atom/proc/clean_blood()
 	. = blood_DNA? TRUE : FALSE

code/modules/mob/living/carbon/human/human_movement.dm

@@ -85,8 +85,11 @@
 					FP.entered_dirs |= dir
 					FP.bloodiness = S.bloody_shoes[S.blood_state]
 					if(S.last_bloodtype)
-						FP.blood_DNA += list(S.last_blood_DNA = S.last_bloodtype)
-						FP.blood_DNA["color"] += S.last_blood_color
+						FP.blood_DNA[S.last_blood_DNA] = S.last_bloodtype
+						if(!FP.blood_DNA["color"])
+							FP.blood_DNA["color"] = S.last_blood_color
+						else
+							FP.blood_DNA["color"] = BlendRGB(FP.blood_DNA["color"], S.last_blood_color)
 					FP.update_icon()
 					update_inv_shoes()
 				//End bloody footprints

code/modules/reagents/chemistry/reagents/other_reagents.dm

@@ -71,7 +71,9 @@
 	if(data["blood_DNA"])
 		B.blood_DNA[data["blood_DNA"]] = data["blood_type"]
 		if(!B.blood_DNA["color"])
-			B.blood_DNA["color"] = list(data["bloodcolor"])
+			B.blood_DNA["color"] = data["bloodcolor"]
+		else
+			B.blood_DNA["color"] = BlendRGB(B.blood_DNA["color"], data["bloodcolor"])
 	if(B.reagents)
 		B.reagents.add_reagent(type, reac_volume)
 	B.update_icon()