Digital Cinema Projector Colored blobs or halos on image

Colored blobs or halos on image.

The symptom of this issue is colored blobs or halos in the image area.  The color of the blob will vary based on where the problem is occurring.
Image showing oil ingress
The most likely cause of this issue is oil, or other foreign substance, getting into the light engine between the DMD chip and the prism.  The DMD chips sit directly on the prism.  On the back of the DMD chip there is either a liquid cooling jacket or a heat sink, depending on the size and model of the projector.  A heat transfer grease is placed between the DMD and the jacket or sink.  This grease has been known to liquify and work its way between the prism and the DMD.

The solution would be to remove the DMD and cleanse the prism of the oil.  While there are companies that perform this service, it is a costly service.  It has to be done precisely in a cleanroom like environment and the alignment is critical.  The price can be further compounded if the DMD chip and it's format board are also damaged by the oil.  Careful consideration should be made comparing the cost of repairing the light engine, replacing the light engine or replacing the projector.