Black streaks on S-VHS tapes? Demodulation noise/bearding?
 

So I've digitized a handful of S-VHS tapes recently, which aren't all that common it seems. I noticed that Philips VR1100 deck seemed to output black streaks in some spots with hard white/black transitions. I've seen it happen on 1-2 normal VHS tapes as well but otherwise it doesn't. I first thought it was just something with this deck, though I also saw it to a much lesser degree on one tape my JVC HR-S8500 (which hasn't been use much from what I could see, but I could be wrong.) so I don't know if it's a more general issue with S-VHS and aging decks. I presume S-VHS is more likely to be affected by this than normal VHS due to the higher detail. The specific tape didn't have the issue in our Panasonic NV-HS1000.

I made a test tape with a JVC SVHS camcorder and managed to reproduce it though it's not as noticeable here as on the mentioned tapes.
You can see it on the date stamp in the bottom right, on the Panasonic AG7350 broadcast deck the streak is not there. This was just a quick test tape but it had it on several spots. There was also one spot (other attachment) where the AG7350 showed a streak but not the philips, though that could also be a dropout or something.
Attachment 9247
Attachment 9248


this would suggest that it is demodulation noise/bearding and that adjusting the white clip, or signal level before demodulation may help here.

The Philips (like the similar JVC decks) seems to need the special JVC/Philips service remote to do adjustments though. Didn't check on my JVC yet, it's a bit older but it might have the same problem. Has anyone managed to obtain remote codes for these remotes?

Many decks seem to output these streaks when the heads are dirty, though in those cases there is normally a fair bit of noise as well, so it's more likely due to the noise. That wasn't the issue here though.

Head wear is likely. Different degrees on different decks leads to different playback qualities.

No all recorders did a proper job either.

Not all S-VHS tapes were equal, like VHS. For example, Maxell S-VHS tapes were pretty crappy. So I'd need to know more about the exact tape brand and model.

That's a good book if you've never read it. I bought it some years ago, read it, then forgot much of it. Time to read it again, probably write some guides on this site based off the info. If you're into video, it can be interesting. But the jargon can get pretty thick. I paid under $20 for a near-perfect copy. I'd seen it sell for $75 at times in years past.