It amazes me that it is possible to create the texture of glass, one of the smoothest, most reflective surfaces available, with a rough medium like pastel on an even rougher surface such as Wallis sanded pastel paper. Just like everything else done in 2 dimension, it is all illusion. The process begins with the relationship of values–matching darks and lights and placing them next to one another creates the illusion of depth and space in 2D. The addition of color should always enhance that appearance, not detract from it or take precedence over it. If the structure of a painting does not work in monochrome, it will likely not work in color–color cannot “fix” a poor drawing or unbalanced composition. A good understanding of the relationship of values is key to any successful painting. Even if you are painting in an abstract style, you still need values to create depth and form, without them the art will appear flat. A range of 3 values is a good place to start, 4 or 5 will create a greater sense of turned form and subtle variation. For example, it is the dark shadow areas of these back lit bottles that give the intense greens the illusion of transparency and almost a glow. But if you look closely at the areas in light, you’ll notice subtle differences in the values of the greens used on the glass–some are darker while others are very light and bright, it is a gradual and subtle change that gives the bottle its cylindrical form as defined by the light. Look for those subtleties and use them to your advantage to create the illusions you want to present in your work.