indigo blue, black, dark green, cerulean blue, lilac, yellow ochre, true green, apple green, ultramarine, and white. Touches of many other colors similar in value are also added.
Make a detailed outline drawing. The easiest way to transfer this highly complex image onto paper is to print a picture matching the exact size of the drawing. Then, use a window’s daylight to draw the outline. An opaque projector comes handy, too, if the picture must be enlarged and the lines redrawn for accuracy. Use coins or other round objects to make circles for the marbles. Use the ruler to draw the lines of the vase
I suggest you start drawings with the shadows (the darkest darks). Meticulously draw the entire image with varied pressure and sharp point of “black” pencil – the underpainting. It is the most important step in drawing glass because it sets the stage for an accurate representation of the forms. It’s helpful to draw from the grayscale reference photo only at this point. Mark the highlights, painting around them with lighter pressure. Strive to keep the marbles round by carefully shading the dark background behind them. Burnish the surface with the mineral spirits and wait till it dries.
You can introduce a variety of local colors into your picture by layering them over the black underpainting. Apply “cerulean blue” and “dark green” in the vase, marbles, and their reflections, while using a mix of “yellow ochre” and “cerulean blue” to cover the lighter areas in the vase. Add “Spanish orange” or “yellow ochre” in the yellowish reflections
It is optional to burnish the color surface with turpenoid now. Add more of the same colors over the dried layer again. Use “ultramarine,” “lilac” and “apple green” in the marbles and their reflections. Keep some edges of the vase blurry and soft, and with a sharp pencil reinforce the lines closest to the center of interest
In this final step, smooth the surface even more with a colorless blender and soften the edges with “white” around every highlight. Because it’s a glassy, shiny surface it must exhibit minimal texture and appear very smooth in both the marbles and the vase.