A July 17 Metro article mentioned how well Metro art is being received by commuters, local business and residents. The accompanying picture showed an appreciative pedestrian enjoying the mural "Penguin Rush Hour." But nowhere was the artist mentioned.

The mural (eight feet high and 100 feet long) was created by my wife, Sally S. Callmer. It took her two years of planning, seven months of eight- to 10-hour workdays, seven days a week, in a very small space (our spare bedroom) to complete. I along with one of my helpers and the designated hanger from the Metro Art project hung the piece during the coldest, most miserable week of the year in January of 1989.

Until Silver Spring bought the mural almost a year later for $15,000, I owned it; paying for all the materials and including my time in both the design and actual hanging for free. My helper was paid for his work week by the Metro Art project. This remains the only work my wife Sally has sold to date, and with good reason: aside from winning numerous awards in art shows, publicity for her work has been nil and none.

Thankfully, the "Penguin Rush Hour" mural is not going unnoticed by The Post. However, while the appreciative pedestrian has his name printed in the picture's caption, the artist's name has once again been omitted. Please let us end this struggling artist's syndrome by giving some notice where it is certainly due. THOMAS H. THOMPSON Bethesda