VHS horizontal lines of discoloration on side of frame?
 

Hello! I've noticed on a number of old VHS tapes I have been transferring there is noticeable discoloration on the side of the frame. Usually its just one side or the other. Sometimes it is a purple hue, sometimes it is a radical hue shift, and other times it is just a noticeable lack of chroma. I'm not trying to 'fix' it, I am guessing it is inherent, but we digitize for preservation clients and I would like to know how to correctly identify it for the condition assessment. Does anyone have any idea what causes it or the best way to describe it? I've attached an example.

This is very common with old VHS tapes. The recording camera or VCR was the culprit.

There's really nothing you can do about it. The only fixes leave artifacts, so the only way to remove it is to just mask the entire area in black and re-center the image. Odds are, it was data than fell into the overscan anyway.

What about all that ugly moire in the posted image? Is that supposed to be there?

Thanks! How would you describe it then to a client that wanted to know what it was? "Discoloration on the side of the frame from dub machine"? These particular tapes are all copies and all seem to have the same problem.

The moire is just something from taking a photo with my phone off a computer screen, it wasn't on the actual video

That could be one explanation. Sometimes such discolorations will disappear when tape is played on another player. Because the source is a duped tape, border discoloration because of inversion of the U and V channels as well as edge tracking differences aren't the only problem you have to explain. What about distortion due to time base errors (did you notice that the side borders are warped toward the left at the top of the frame)? What about the broken top border (horizontal border line split near the top left edge)? What about color balance problems, crushed blacks, and blown-out highlights? Or would some of these problems be due to the way the image was made?

Sometimes defects can be resolved, sometimes not. But if you're dealing with "clients", as you seem to imply, you should know by now how to copy an unaltered frame from a video without having to use a camera, and how to do it with free software. It's difficult to advise about submissions with added defects using images that don't look like the original video.

My bad, here is an unaltered frame using free software as you so kindly suggested

You're regressing?