If you are just trying to brighten a single object in the scene without having more lights affect the other parts of the scene, exclusive group lighting can achieve that. Brighten the group light and you only affect that object. By parenting the group light to the keylight in your scene, shadow matching can be achieved as well.
It still seems to apply. The texture colors on the group lit cube are richer and brighter than the basic cube while still retaining the shading aspects that are lost when you crank up emit.
You can go the nodes route, but I have run into shadow casting bugs using texture nodes with alpha mapped images, so be warned. You might be ok with procedural.
try my cubes attached. either map to Ref, or Emit, either with Add, or Mix blend mode, or a combination. Rendering to EXR shows that Ref+Emit with Add gives the brightest. (Ref=reflectivity (or light), not mirror reflection).
RickyBlender, I think you can get the effect you are looking for by creating a another texture for the same material and map the new texture to the “emit” value only. Here are two renders… the first is just a simple cloud material lit by the default lamp, the second has a sphere blend texture applied with the mapping going to “emit”.
Hmmm… in the attached file I added a color band. This is for the texture that is mapped to the emit property. Just play with the sliders at the bottom of the colorband called Bright and Contrast to change either attribute. Not enough? Add another texture mapped to the emit property!
hmmmm, may I suggest a totally different approach? Consider a textured light. THe main problem with this is that you can only apply textures and not materials to lights