Jeff, not quite sure what you're looking for, but for me, digital negatives are files of the images "as shot"; in other words, what comes out of the digital camera before you do any modifying in your image editing software. You should save these somplace more secure than your computer's hard drive (mine go to DVD). This is done because, sooner or later, you'll want to go back to the original file for another attempt at creating that perfect final image.

"Digital negative" is just a term coined to describe these unmodified digital images as analogs of film negatives.

I consider properly post processed digital files at full size to be the negatives. The original digital files get archived and probably never touched again.

Bill;
Thank you for your rapid response. I better understand now. I agree with transfer to DVD. I have learned that once a copy of an image has been made, "artifacts" begin to appear in the image. Stock photography agencies do not accept images with artifacts. If I burn images to a DVD then later retrieve an image from that DVD will artifacts be present?

Larry;
Thank you for responding so quickly. Now I better understand. A prospective client wanted digital negatives of a party which I was going to shoot. I lost the prospect because I did not know about digital negatives. Life is a learning experience.
Jeff

Assuming that by "artifacts" you mean things in an image that don't belong and weren't there when you burned it to DVD: In the short term, at least, the answer is no. There should be nothing in the image when you retrieve it from DVD that wasn't there when you burned it. It helps to remember that images on a DVD, external hard drive, floppy disk or whatever, are just data, and if the data is safely transferred from one medium to another should be an exact duplicate of the original. There are a couple of caveats here: First, use only good quality DVD products. Avoid the cheap stuff at the dollar store. Second, use good, reliable software to burn the image to DVD, one which has an error-checking routine to verify the accuracy of the transfer.

In the long term, there is an ongoing question about the long-term archivability of DVDs in general, but that's a problem we all face...

Here's the deal when working with JPEGs. If you use the Save or Save As command to rename or to transfer images to a different folder, compression happens again the the image is slightly degraded. If you copy a JPEG, there is no change in image quality. If you're working with uncompressed files, like TIF or PSD (native Photoshop files), there is no degrading when copying or using the Save or Save As commands in your editing program. Like Bill said, images when copied should be exactly the same unless you're having a hardware problem.

Establish good working methods. When editing an image, always work on the file in an uncompressed state. You can shoot JPEG but convert to a TIF (or other uncompressed format like PSD) before doing any editing. Then save your final post processed file in that uncompressed format as your master or digital negative. Then if a JPEG is required for submission, resize and save at a quality lever that doesn't visually degrade the image or meets the submission requirements. If you're submitting to a stock agency you need to add your copyright and key words to the meta data. In Photoshop it under File>File Info.