From: 0004861036@MCIMAIL.COM (James Millick)
Newsgroups: rec.video
Subject: Tape Question, TRINITONE and Betacam Questions
Date: 22 Nov 92 19:40:00 GMT
Distribution: world
Organization: The Internet

Jennifer writes on
|>Subject: Simple question re: vcr cleaning
|>Message-ID: <lott.10.0@egr.msu.edu>

|>I have a couple of questions regarding vcr cleaning and my 
|>snowy picture when I tape.   My Panasonic vcr is 5 years old 
|>and I've been taping soap operas 5 days a week for about 4 
|>years. I took my vcr in to be cleaned by a reputable 
|>electronics company about a month ago.  My picture today is 
|>almost completly snowy, but the sound is great.

  One or both of your video heads is clogged, probably with a 
piece of oxide. The linear audio head is separate, thus not 
affected by the clog.

|>When I took my vcr in, the guy said they would clean it but if 
|>you go back to using the same tape, it will gunk up the heads 
|>again and you'll be back where you started.

  Your technician is right.

|>My problem is that I have a roommate who also uses the vcr to 
|>do aerobics with and uses the same tape.  Is there anyway she 
|>can clean her tape when I get my vcr cleaned so we don't have 
|>this gunky problem with the heads?

  You don't say whether your roomie's tape is prerecorded, or is 
she taping a daily aerobics program. Tape is, simply put, rust 
glued to polyester film:

Edge view (not to scale):

top
________________________
oxide
------------------------
adhesive
------------------------
polyester film
________________________

bottom

  What is happening is that some of the oxide is coming off the 
tape and getting stuck in one or both of the video heads. A video 
head is a very small c-shaped element mounted in the video drum. 
The gap in the head is so small you can't tell if it's clogged by 
looking at it without magnification. If a piece of oxide (or 
other junk) gets stuck in it, the picture goes snowy, as you've 
seen.

  Tapes have a definitive life span, you shouldn't play them over 
and over past a certain point. After they reach a certain number 
of plays, you should record something that you are going to keep, 
but only look at a few times a year, and start using a new tape. 
If your roomie's tape is prerecorded, it's time to buy a new one. 
For your daily soap shifting, you don't say how many hours you do 
per week. Remember both record and playback time. I wouldn't 
recommend using the same tape for more than 4-6 months, and that 
could be pushing it based on how many hours a week you use it.

|>Any other suggestions?  Please e-mail me personally.

  I've sent one copy to the net, with the CC to you.

  Use high quality tape. Anything else is a false economy. It 
might be less expensive to _buy_ cheap tape, but it isn't as 
cheap to _use_ as good tape. Cheap tape doesn't last as long and 
is more prone to shedding oxide than good tape. If you buy 10 
good tapes at a time mail order, it really isn't that expensive. 
J & R Music in NYC (1-800-221-8180) advertises my preferred VHS 
tape (I mostly use my Betamaxes), TDK HD-X Pro T-120s for 
$64.90/10. That's $6.49 each, which is pretty reasonable. S & H 
is $4.95. Ask Santa for a box of 10, get the deck cleaned, and 
retire the old videotapes permanently.

Jim Millick
Video Reviewer
The Perfect Vision

*****************************

Preston Mullen writes in
Subject: "Trinitone", was Re: XBR^2 <Bxu2Lu.7o@ra.nrl.navy.mil>

|>Jim Millick's remarks about color temperature adjustment of 
|>XBR^2 reminded me that the KV20EXR10 has a "Trinitone" 
|>adjustment, which I take to be a color temperature adjustment 
|>with "high" and "low" settings.

  The first of the XBR family, the KV-25XBR had this as well.

|>However, I'm not sure I can see any difference between the two.  
|>This is complicated by the fact that switching the setting 
|>causes a distracting blue "TRINITONE HIGH" or pink "TRINITONE 
|>LOW" label to appear at the bottom of the screen for several 
|>seconds.  I tried looking at a small area of the screen, we ll 
|>away from this label, close up through a paper tube, and I 
|>think I detected a slight change in the color balance of a 
|>white area (the blue phosphor stripes seemed to get a little 
|>brighter in the "high" setting, etc.), but I'm not really sure.
|>So, is TRINITONE real, or is it a placebo feature?

  Yes, the TRINITONE feature makes a difference. The next 
question is does it work right? I remember asking Joe (Kane) 
about this, and I thought he said the low setting was either 7200 
or 7700K, neither of which is low enough. What's more, I have no 
idea if it will track a gray scale (keep the same percentages of 
red, green, and blue through all shades of dark gray all the way 
up to white) at any of the color temperatures. My guess would be 
that it would least likely track at the lowest color temperature. 
Not to mention it will have auto tint at all color temperatures, 
which means it won't properly decode NTSC composite to RGB.

  One last note about Preston's Betacam question. The biggest 
strength of Betacam is that it is a *component* format, it 
records a red, green, and blue channel (*composite* records a 
luminance and chroma signal). If it can stay in RGB, it 
completely avoids encoding and decoding, two trouble areas. It 
can't be transmitted this way at present, of course. One thing I 
hope we get with NTSC's successor is a component video format. 
This would greatly reduce a lot of different problems we now 
have. It would, unfortunately, eat up bandwidth as well, but you 
can't get something for nothing.

Jim Millick
Video Reviewer
The Perfect Vision
221924ZNOV92