Thanks Vern--
I may have to resort to re-working. Further clarification tho! This is not the first time I have turned on this particular light in the cho, but is at a point where I have half of the lights on. If i turn up the intensity on this light at this keyframe there is no ilumination in the workspace until I turn another off. Then my light magically comes on and illuminates my subject clearly.
I have read in the tech ref. there is a cache limit on number of objects in memory at one time where adding another object will release the least recently used object in memory. This description is under the animation topic. I suspect this is what is happening but can't find any way to change the cache setting. By the way, I am running version 11 on a PC.
Any more thoughts would be appreciated.
John