from UDE's Judge Certification Program (YGO)
Q:
If "DNA Transplant" ( attribute light) and "Light-Imprisoning Mirror" are active on the field and I tribute an "Exiled Force" for its effect, will "Light-Imprisoning Mirror" negate the effect of "Exiled Force" at resolution?
A:
If a monster whose Attribute is changed to LIGHT while on the field becomes a Non-LIGHT monster when its effect resolves, its effect will not be negated by "Light-Imprisoning Mirror".
The effect of "Exiled Force" is not negated in this case.
http://entertainment.upperdeck.com/community/forums/thread/1561833.aspx
Q:
If "DNA Transplant" ( attribute light) and "Light-Imprisoning Mirror" are active on the field and I tribute an "Exiled Force" for its effect, will "Light-Imprisoning Mirror" negate the effect of "Exiled Force" at resolution?
A:
If a monster whose Attribute is changed to LIGHT while on the field becomes a Non-LIGHT monster when its effect resolves, its effect will not be negated by "Light-Imprisoning Mirror".
The effect of "Exiled Force" is not negated in this case.
http://entertainment.upperdeck.com/community/forums/thread/1561833.aspx