Reviewing the new REN Perfect Canvas Smooth, Prep & Plump Essence. REN skincare has just launched the amazing Perfect Canvas Smooth, Prep & Plump Essence. This bio-ferment essence is designed to enhance the benefits of your skincare routine and fortify your skin barrier. Personally, I’m a big fan of this product and I’ll share all the details below. But first, let’s talk about essences in general because I know it can be confusing for many people – where to apply it, is it a toner, what does it do, and do you really need one? Let’s clear that up!