They are different elemental damage that you can get with special and heavy weapons. Also the sub classes are them too. Here is a list Light blue = [b]Arc[/b] Orange = [b]Solar[/b] Purple = [b]Void[/b] Titans and warlocks both have a [b]void[/b]subclass Hunters and warlocks both have a [b]solar[/b]sublass Titans and hunters both have a [b]arc[/b] subclass The shield on some enemies in PvE is the type of elemental damage that would do the most on them. Hope this helps!

The colour type has no impact on damage out put unless there is a modifier on the strike/raid i.e nightfall has a solar modifier on so you will do increased damage with solar weapons but the enemies with solar weapons do more damage to you. It also plays a general role of taking out sheilds, minatour have purple sheild so use void damage to lower sheild quicker, fallen captain has an arc sheild so use arc damage to lower his sheild quicker and finaly the wizards have a solar sheild so use a solar weapon to drop the sheild quicker. Why is the sheild so important?, when the enemys sheild is up no matter if you hit them in the head they will only take a set amount of damage so no criticals can be done, also your damage is reduced against the sheild unless it is the right eliment match. After the sheild has droped any type of weapon can hurt them, youll notice if you use the wrong weapon on a sheilded foe it will say 'immune' this is becaude you arent using the right eliment to lower the sheild and are doing lower damage.

Until you start getting into the later levels it's not that important. But once you're doing the level 28 missions those shields will "resist" all damage except for the intended element. On lower levels you can take down any shield with any damage type, but using the right damage type is faster.

Blue = your normal damage (what you would get if you're just aiming anywhere on the opponent, without hitting certain critical spots) Orange = critical hit damage (certain spots, like head and some vex glowing parts, walker legs, etc.) Purple = ...there's purple damage? (I haven't seen any, so I'm confused)

Orange/Red damage is Solar. Light blue damage is Arc (electricity) and purple damage is Void. Now, as far as I know, special and heavy weapons can come with typed-damage and these weapons are required to take down enemies with damage shields. Take Hive Wizards for example, or Cabal Colossus. Their shield (that red glow aura) is Solar based and therefore resists all damage [b]except[/b] from a Solar weapon. The way to defeat them then is to use a Solar-type weapon, let's say a fusion rifle or shotgun up close or a sniper rifle... strip the shield then questions quickly switch to your primary weapon and finish them off. Rinse repeat for other damage types like Void and Arc That's way each character can carry multiple weapons at any given moment. 😎

Orange is Solar damage, represented by the flame icon on the weapon. Purple is Void damage, represented by the purple swirl icon. Blue is Arc damage, represented by the spark looking thing (sorry, I have no idea what it's supposed to be lol). For the most part, only Special and Heavy weapons are able to deal these types of damage. The purpose of these is that some enemies are more susceptible to one type of damage. If an enemy has an overshield, the color of the shield (you'll see after you shoot at it) lets you know which type of damage to use against it. For example, you shoot a Wizard and you see an orange glow around it, that means it is susceptible to Solar damage. Using a Fusion/Sniper/Shotgun/Machine Gun etc. with that damage type will hurt it way more than your primary weapon, which only does Kinetic damage (with a few rare exceptions). I hope that answers your question and was helpful. That's about all there is to know about it, to the best of my knowledge.

one of the huge things you need to focus on is just finding a PRIMARY legendary/exotic weapon that does a different type of damage than "kinetic" or normal damage. there are many ways to do this, however I got my Void AR in the Vault of Glass. im not sure if the iron banner will be selling any like this. at the same time you also need to be trying to get legendary/exotic special and heavy weapons for all 3 damage types.

Orange takes down orange shields blue takes down blue shields and purple takes down purples shields its as simple as that. Some strikes such as the nightfall tell you a certain damage type does extra damage so use the corresponding weapon