Transparent objects provide wonderful opportunity for practicing the concept of dividing up space to create a balanced composition. The overlapping areas and reflective surface of glass offers a wide range of geometric forms and repeating shapes. The values in the shadows of these forms create a rhythm of their own that takes precedence over the objects themselves.
For example, there is a compositional guideline that many representational painters follow almost literally–not placing an even number of objects, particularly just 2 objects, in the composition. The above is an example of how 2 objects can create a balanced layout from the shadows, transparecies and placement in space chosen during the initial design of the composition.
For this piece, I began by placing the major shapes of the bottle on the right into the composition–the flattened oval of the bottle’s body, the round-edged rectangular bottom, and the top ellipse of the neck. All of these are placed directly on center of each other (I drop a center line down the middle after placing the first shape). Next, I connect the verticals, when satisfied that the first bottle is proportionately correct, I move on to the next element. I use the first bottle to gauge the placement and proportion of the second bottle. Beginning with the shoulders of the bottle, I work through the bottom ellipse and top ellipse of the neck and connect the verticals. I now have two forms that overlap, plus a series of sub-forms that were used to initially form the bottles. This arrangement allows me to map in the dark and light values next, creating a balance of dark, medium and light values based on the transparency and shadow areas of the transparent surfaces. I also have the additional forms of the shadows on the table top and the reflected light to create more variation in form and value. So in other words, 2 objects taken as a whole are actually a series of many sub-forms that can be used create a harmonious composition.
Color can further be used to strengthen the dynamics of the composition. The darks used in both bottles are made up of cobalt blue and burnt umber, this unifies the two objects in the shadow areas and reinforces the illusion of transparency where they overlap. The use of warm and cool highlights on both objects makes a further connection across the the surfaces of the objects. The fact that the forms run off the page on several sides further reinforces the abstract nature of this composition, even though it is painted in a loose representational style.
Try not to get trapped by taking compositional guidelines as “rules”. Don’t think of your subjects as objects, think of them purely as forms made up of sub-forms. This is also a wonderful way to begin an abstract painting–it provides enough structure so that you have a basis upon which to add the non-represenational elements in the form of value, surface texture and color.