When commercial projectors quote a lumen rating, are they listing the lumens at the screen or at some point inside of the projector? I know this may be elementary, but I want to make sure that I understand fully. Also, if it is made at the screen, then is there a standard distance from the screen that the light source must be placed for proper measurement and is there a standard test pattern or color that must be used?

Thanks

Yes, there are standard test procedures.

Most ratings are done at the lowest rating size. For example if manufacturer X says their PJ projects anywhere from a 60" to 160" image, then you can bet the rated lumen measurement wasnt from the 160" image size.

there are test patterns as well, mainly white boxes and such. Also multi-point measurements (center, corners, top, bottom ect)

Im not a guru on the ANSI procedures, I just know their basic operation.

Thanks for your input. I guess that I just want to know how our LL PJ's actually compare to the commercial units. If there are any real comparisons out there would someone please post a link in here for me to look at?

thanks