A sphere instrument, with the sphere coated white inside, allows you to gather all of the reflected light from the sample to be measured. The rest of the instrument design is often the same as a standard 45-degree instrument.
Sphere instruments offer the advantage of measuring rough and very shiny surfaces well.
For many color mixing applications in industry, this is a good approach. If you want to measure color with a sphere instrument similar to a 45-degree instrument it can be accomplished by allowing some of the surface light escape from the sphere. This is done by cutting a hole in the back of the sphere that can be covered or opened. Measuring color with the hole open is called specular component excluded. Sphere instruments are more flexible and give a range of methods to measure a variety of materials.