I have a document which fits the description.
It is the Electronic Industries Association EIA standard RS-274-D
This is a fairly old document but the address given inside is:

Electronic Industries Association
2001 Eye Street NW,
Washington, D.C.
20006

you should be able to find the association from a web browser.
alternatively, you could contact companies like Lavenir, Advanced Cam
Technologies or Wise. these companies all create gerber viewing
and manipulation software and should be able to assist you in
finding the information you need.
Good Luck
 brendon
 eda technologies.

Bob Bullock wrote:
>
> I need write a program which can read Gerber RS274X files and create a
> bitmap of the image for further processing.  If anyone can point me in the
> direction of any documents which describe how to interpret this format, or
> can email me a document I would really appreciate it. A search of the web
> has come up empty.
>
> Bob Bullock
> KoolKits Electronics Ltd.
> [log in to unmask]
>
> ################################################################
> TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
> ################################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
> To subscribe:   SUBSCRIBE TechNet <your full name>
> To unsubscribe:   SIGNOFF TechNet
> ################################################################
> Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
> For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
> ################################################################

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################