Color me productive.

Q. Where do I find studies on color's effect on productivity and which colors are best?

A. Two ergonomics textbooks are helpful in this regard: Ergonomic Design for People at Work (1983) and Fitting the Task to the Man (1982). Even though they are somewhat dated, the information remains valid.

As far as color's impact on productivity, I'll summarize a few points:

* The Westinghouse Hawthorne Study is famous for the conclusion that any change in the workplace can positively impact productivity, as demonstrated by such things as an increase in lighting leading to increased productivity, followed by a decrease in lighting leading to increased productivity. The key was the attention given to workers, not the changes themselves.

* Much of the research cited is perception-based. This would suggest it is important to ask the people involved what their color preference is. Getting input from the work force increases their involvement and ownership, which should positively impact productivity.

* Intense primary colors should be avoided because of their tendency to produce after-images, which lead to a loss of visual acuity. In general, pastels are preferred for large surfaces such as walls. Darker or richer colors may be used to achieve contrast, such as highlighting exits, safety warnings, or critical equipment controls. If the work is monotonous, include some areas of exciting color.

* Blue is cold and restful, creating the effect of a long distance. Red is warm and stimulating, creating the effect of a close distance. Orange and yellow are considered warm and exciting, which may indicate they could boost productivity. Walls and ceilings painted yellow, red, or blue may be initially attractive, but eventually they will be a strain on the eyes and make a room unpleasant.

* 5S and visual systems make the workplace self-explanatory and self-maintaining. Contrast helps, too. Sometimes it is best to maintain a light color for surfaces, which highlights dirt and debris. You must reinforce cleanliness and routine cleanup to make this work, however. Using color codes for equipment controls as well as equipment picking and return further enhance productivity.

Based on this information, I recommend:

* Use pastels and maintain contrast for critical items.