First posted: Mon, May 12, 08
Many companies create IES files for their fixtures which describe the characteristics of light output for a lighting calculator to use. Halo has IES files for many fixtures and a simple calculator. To experiment with their calculator follow the link and click on the little calculator icon next to the lamp you want which would be 26W TTT. A professional lighting designer uses tools like this, but much more sophisticated, to choose and place fixtures to insure the proper level of lighting in a room and at certain places in a room.