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-   -   timecode/blacking tape (https://www.dvinfo.net/forum/long-black-line/47494-timecode-blacking-tape.html)

Steve Watnet July 13th, 2005 03:05 AM

usually hungry 4 snarkiness
 
Yep, and sorry I was bitchy and KRAZY. I thought a good snarkfest might be enjoyable for the readers, but I never manage to get the snark-outs I want going. Does anyone want to fight about anything? Chris?

Nate Ford July 13th, 2005 11:10 AM

the head-wear thing is real. any mechanism with moving tapes and heads, from 2" analog multitrack audio tape to dv to old-fashioned answering-machines experience head wear. both on the playback and record heads. every camera, deck, etc, has a finite amount of time that one can expect for the heads to perform optimally. there's no science fiction involved.

i have definitely seen analog equipment suffering from worn heads. sometimes, the record heads get worn and the play heads are ok, sometimes the opposite. i inherited a professional quality s-vhs vcr with shot play heads and fine record heads. so i use it for making dubs. i haven't seen worn heads with any of my dv stuff yet, although i've seen plenty of dirty-head problems. to avoid these, i get my heads cleaned professionally every year or 2. but i don't see why it's so difficult to understand that by doubling the amount of recording you're doing, you're effectively "halving" the life-expectancy of your tape mechanism. if you have a 50-mile commute every day, and i have a 100-mile commute, then one of us is going to need new tires sooner, (and eventually a new car.) hint: it aint gonna be you. that's the facts of life. your camera will not last forever. it's full of cheap lightweight moving parts. accept it and move on.

that said, i've been known to black tapes before super critical shoots. i think blacking tapes is a perfectly viable way to protect against tc breaks. it definitely does that, and it definitely doesn't hurt video quality. you just have to weigh the benefits against the (very real) consequences.

Glenn Chan July 14th, 2005 01:26 AM

You can rescue yourself out of TC breaks though. Plus, it's easy to avoid them in the first place if your camera has an end search function..

Doug Boze July 14th, 2005 01:42 PM

Quote:

Originally Posted by Mike Teutsch
When you record on your tape, just make sure you don't go forward and start recording. If you do that, all will be OK! It is only in capture that you can have trouble, and as long as there is timecode, there is no major problem, except another scene.

I think Mike nailed it. Recently I was going through a source tape looking for mark-ins and -outs using PPro. I usually just watch the tape through, doing this and saving the clips as I do so. Then it's select batch capture and take a break while PPro saws through the tape, downloading clips. There were two shots where I had started recording without allowing sufficient pre-roll. As a result, the timecode advanced abruptly near my intended clip start. PPro tried valiantly to position the tape, but gracefully gave up and finished everything else up. I had to go back and manually capture those two shots. If only I had been rolling at least 30" before, I could have saved myself many minutes in post!

I think the main benefit of blacking (or striping, bars with or without tone) tape is to retension or repack it. Ideally, this should be done at write speed in the camera, but even fast-forward and rewind will help, even in another deck. However, I don't think this is as important with digital media than it was with analog recording, where the least hitch in transport could blot a shot.

Doug Boze July 14th, 2005 01:54 PM

Up resing uprising
 
It just occurred to me that if you are downloading low-res or proxy clips, you are going to have to repeat the whole process again later at full resolution. So there is actually more tape handling involved than with just working with full-res captures from the get-go. I can understand, tho, that if the situation demands field editing on a "challenged" platform, it may be of benefit.

BTW, all this talk of wear and tear has been about the heads of the VTR. Something more likely to show up as trouble is wear on the tape from constant shuttling and scrubbing. All it takes is a slight mechanical misalignment or a change in humidity or temperature, and something akin to head wear can appear. The trouble is, there is no fix for this.

Stephanie Wilson July 15th, 2005 08:02 PM

Wow, I'M confused.....

Back in the day, you blacked a tape to have continuous time code to be used on an INSERT ONLY edit master.

I've never heard of the need to black a record tape. However, it's very possible I'm missing something here...

In my opinion if you shoot with TIME OF DAY timecode at NDF and have an "end search" or equivalent function to make sure you are on the last frame of previously recorded video, you shouldn't have a DROP in time code. You will however have a BREAK in time code, as the time of day will have changed between set-ups but I have never had a problem capturing with this time code arrangement. And I certainly wouldn't put those extra hours needing to black my record tapes on my camera record head.

Hope this helps in some small way.

Stephanie

Nate Ford July 19th, 2005 09:22 AM

yeah, blacking with dv is a different thing than in the analog days when you blacked your rec tape for insert editing. the camera will start writing timecode based on the timecode at which the tape is currently positioned. the problems happen with some cameras when you turn the camera off, if the tape creeps just enough so that when you next turn it on, the heads are over "virgin," un-recorded, untimecoded tape. if you start to record at that point, it starts over at 0:00:00:00.
with my students with cheap cameras with no end-tape search, etc, i just always make them record an extra ten seconds when they're going to be shutting the camera off, so they have something to write over if the use the manual rewind method.

Chris Ivanovskis August 4th, 2005 03:53 PM

i've done both and honestly never had a problem. the last music video i shot i pre-striped the tapes and had no problems. allowing the tape to roll on an extra 10 seconds + also is great. i think as long as you are careful you can go either way.

i only buy MQ panny tapes and if i black them the tape is only recorded once after that. i black them with a cheapie sony deck and record with my xl1. i've never had a problem with quality loss in my pictures, but i've never dropped a frame either. when i'm doing something like a music video where its EXTREMELY important that my audio syncs up i prefer to black them. it also makes batch importing extremely simply. but thats just me. i'll do what works for me until i have a problem, then i'll adapt.

Germain Jung August 5th, 2005 05:52 AM

I 'm used to code all my tapes before use and I have made the experience that blacking tapes does not only write a time code on it, but I also have much less drop out problems on coded tapes than on virgin ones. I use the black & code function of FCP to do it.

As someone from TDK explained me some time ago, at the first contact with a head drum the tape is straightened and a potential drop out place will record much better while the later real shoot.

Dean Sensui August 5th, 2005 02:55 PM

Blacking DV tapes is a waste of time and puts unnecessary wear on equipment. It'll shorten your useful head life by at least half (half of it consumed recording absolutely nothing useful) and put another pass on a tape that has a very limited lifespan.

Also, when a camera records onto a tape, it isn't inserting video onto existing tracks but erasing the tape and writing completely new ones. So although you'll have time code after the break, it might not be perfectly continuous time code and you might still face other problems because of that.

Best just to post-roll five seconds after the take to ensure continuous time code if you really have to review material in the field, and park the tape in that post-roll after review to ensure continuous TC. If that doesn't work, then the camera needs to be serviced.

In hundreds tapes I've shot and handled from me and other shooters, the only times I've had time code breaks was because the above-mentioned post roll procedure wasn't followed and someone either looked at or re-inserted the tape.

Imagine if all those tapes were blacked in advance -- that represents a couple weeks of non-stop camera time!

Stephanie Wilson August 5th, 2005 07:39 PM

Quote:

Originally Posted by Germain Jung
I 'm used to code all my tapes before use and I have made the experience that blacking tapes does not only write a time code on it, but I also have much less drop out problems on coded tapes than on virgin ones. I use the black & code function of FCP to do it.

As someone from TDK explained me some time ago, at the first contact with a head drum the tape is straightened and a potential drop out place will record much better while the later real shoot.


Hey all,

I've been doing this professionally for 20 years but am still learning SO MUCH from this forum. Thank you all so much!

The protocols change of course over the years with the release of every new format. I learned to fast forward/rewind and repack on 3/4" tape. I didn't think this was still necessary with mini-dv tapes. Am I wrong? Plus, I'm not sure how to answer Germain's question as I guess I don't really understand the question. Germain, please try again...

Digital tape isn't subject to dropouts.

Steph

Glenn Chan August 6th, 2005 12:14 AM

Stephanie, DV is prone to dropouts although they may be so rare (for you) that you don't see them.

WEbsite with pictures of dropouts:
http://www.adamwilt.com/pix-defects.html

If you really want to cause a dropout, you can open a mini-DV cassette and blow dust into it. If the dust is small enough and aligned right, it won't cause a dropout because DV has error correction.

2- Re-packing might still be a good idea for DV??? It's still magnetic signals being recorded onto the tape... albiet digital video involves higher frequencies than analog.

Germain Jung August 6th, 2005 01:58 AM

Quote:

Originally Posted by Stephanie Wilson
I learned to fast forward/rewind and repack on 3/4" tape. I didn't think this was still necessary with mini-dv tapes.

Hi Stephanie,

Perhaps this is not necessary with the DV format, but as I wrote I have much less visible drop outs with my coded tapes than I used to have with uncoded tapes.

I never would use the camera for coding, I do that on a DHR-1000 and I also don't waste my time waiting while the tapes are coded, the machine gets it done alone.

If I have the possibility to avoid a drop out, even if I need to clean the heads of the deck more often, an do the service sooner, I'd do it.

Quote:

Originally Posted by Stephanie Wilson
Plus, I'm not sure how to answer Germain's question as I guess I don't really understand the question. Germain, please try again...

Ok, I would try again, but I didn't ask a question, it was an explanation of why the tape will record better after being coded.


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