I am making a custom map in vanilla Minecraft, and am trying to create light without a source block. The reason for this is that I don't want the clutter of torches, lamps, glowstone etc. Simply put, I want an invisible light. Is this possible?
You can do what Spyfiend did, but I also have a solution to this. It's basically the same thing what he said, but mine is with carpet. So if you want to act like you have invisible light you can use sea lanterns/glowstone, then on top you could put carpet that matches the build in your map.
Assuming you're putting it in a hallway or room, you can put a transparent block on the ground on top of a glowstone block (Or other light source block), an example would be to put pistons or carpet down as the floor, and under that put your light source. You can also make a 2 block deep indent in the wall, put in your light source, then put a sign on the light source and a painting on the sign to cover it.
Another thing you can do that's out of the way is put beacons on the floor, but then the source is obvious.
If you turn off DoFireTick you can put down a grass block, use bone meal on it twice to make tall grass, then light the top of the grass on fire and brake the bottom bit of the tall grass. This last method isn't ideal though because if you put a block under where the fire was it will ignite. You can also hear the sounds from the fire if you're close to it.
Simplest options would be 1. Mandatory texture pack and change the texture of the light block to something normal like stone bricks or something you're naturally using in your builds (or maybe make it transparent) 2. Download a plug-in that allows you to change the transparency of certain blocks, not the visual look though.
You could try adding the light into the build to blend things in such as; Manapools (sea lanterns), diseases (glowstone), or even treelights (glowstone)
If you get the Silents's Gems mod, then you can get "phantom lights", which do emit colorful orbs that disappear very fast, but if a block is placed on them, it will replace it. the light is quite strong though, consider getting the mod.
There is a mod that makes this possible. I do not remember how it's called exactly,but it begins with "W". The thing with this mod is that there are some blocks that generate replacements for the air blocks that will iluminate themselves the area. The problem is that you can't place any more blocks in the "modified" air blocks. My idea is to use the /fill command in the desired area and place the "modified" air blocks. Otherwise,in Vanilla Minecraft,you can only "fake" this by placing,for example,lava behind a glass,jack o' lantern under carpets,etc.