At my company we created proprietary software that we use only internally - we do not distribute this software - to generate reports from client data. We sell these reports to our clients, not the software.If we were to link to GPL licensed software from our software, would will still need to (upon request) provide our proprietary source code?I understand that if we distributed our proprietary software itself, the answer would be yes. And I understand that if we used the proprietary software only for internal purposes, the answer is no (e.g., see discussion here). But if we only use the proprietary software internally, in order to generate a report product that we do sell (distribute) to customers, then what is the answer? This link seems to suggest probably not, but what if the GPL software creates a particular image that is displayed on one page in a many-page report?Thanks in advance for some clarity on this. Legalese is so hard for me to understand, but if you could also point me to the particular sections of the GPLv3 that make this clear, I'd appreciate it.
Do I have to distribute my commercial source code that links GPL software if I only use this commercial software to provide a reporting service?
licensing;gpl;commercial
For the regular GPL, the answer is no. Quoth the FSF FAQ:Q: Is there some way that I can GPL the output people get from use of  my program? For example, if my program is used to develop hardware  designs, can I require that these designs must be free?A: In general this is legally impossible; copyright law does not give  you any say in the use of the output people make from their data using  your program. If the user uses your program to enter or convert his  own data, the copyright on the output belongs to him, not you. More  generally, when a program translates its input into some other form,  the copyright status of the output inherits that of the input it was  generated from.In this case, you are the user of the GPL'd program, so the output is all yours.It's worth mentioning that if we were talking about the AGPL, and your clients were interacting with [the software] remotely through a computer network, then the answer would be very different. But it sounds like neither of those conditions apply to your case.