Texture. Diffuse reflections and light often fail to reveal the texture of the object. A shallow angle of light reveals the texture. Highlights and shadows. This may also cause similar problems to those created by low angles in copy photography. Uneven lighting. As before it can be resolved by placing greater distance between light and subject. Small light sources also help. Small light sources produce sharp hard shadows. Dark subjects may require a different approach. Black objects don’t creat the diffuse reflection to give firm to surface textures. We can increase the exposure, although this may cause detail in the highlights to be lost. Another option is to creat a direct reflection with a large light source (overcast sky, soft box or reflector). The light is positioned above the subject. Not raking across the subject. In the example from the book the reflective properties of the object is used to record the subject at its best.
Subjects are varied. They are not usually simple. Some areas need a diffuse light others direct reflection. Consider what is important in an image and light for that. Or apply both principles to the subject. Problems can not always be solved. The competing elements cannot always be balanced. The problem cannot be solved.
Try a lens polarizing filter. Easy but least likely to work.
Use a still larger light. This will produce a range of reflections. Both within and without the family of angles. Compromise.
Use more than one light. Similar to previous option but easier to control and refine. Again a compromise, but a better one.
Use a Gobo. A Gobo is anything that goes between light and subject. To block out part of the light and it’s associated reflections. Can be difficult to set up. Close to subject it may produce shadows. Closer to the light it might reduce the overall illumination. It needs to be the right size to block the required area but not the others.
Are single surfaces that require both direct and diffuse reflection. Example: glossy wood. Direct reflection to show the gloss. Diffuse to show colour and grain. Careful use of a gobo to reveal both elements.