What's best

Paul, hello! We prefer JPG's so you are good to go! In reference to the questions about artifacts, I have not had anybody that's had any concerns with this. I'm doing a little research and you're welcome to check out this link for more info: http://www.wikihow.com/Improve-Jpeg-Image-Quality Since I have not had any feedback or concerns with jpg artifacts I believe this is ultimately subjective. Please let us know once you upload the file if you have any concerns regarding artifacts, etc. If you want us to take a closer look at any point to the project itself you can always email your project ID number to support@prestophoto.com. Best PrestoPhoto support support@prestophoto.com

I forgot to ask what the best file extension is for your process? I have been working most of my pics into JPEG as the need for compression dictates this. I have worked some of these files several times and I am wondering about resulting image quality when it comes time to print. Would I benefit more from saving these in TIF then zipping them to be printed or can JPEG files suffice? If JPEG files are good should I remove the artifact to insure better end results? Paul