How a hyper texture can be created in the DTE, that creates exceedingly high positive and negative values, is explained in this tutorial. The scenes explained in the videos demonstrate some of the applications of such hyper textures for transparency, reflection, specular, etc.
They can be applied to individual objects in the scene so that some cast shadows and others the opposite of shadows - light. Speaking of light, they can be used to generate light through a gel for TA renders without any HDRI at all.
Special high contrast gels are provided in two resolutions that are transformed to match the HDRIs included, so you have the option to either use a special derivate of Obscure Gel Light rendering with True Ambiance or go for an IBL render.