CompuServe Messages

#WFM V-Scope Techniques

    06-Feb-95 23:09:40
Fm: Wayne Cole 76370,621
To: Steve Bennett/SYSOP 76702,1071
John, I'm not sure why you should be concerned about RGB values. What matters is what comes out the spigot to the final tape/program feed, etc. I haven't tested Pinnacle (don't have on as yet). BUt I have looked at the bars from the toaster alot (I have two of those). With the Waveform Vector scope, the Toaster bars are dead-nuts on in both intensity and phase. And that's all that matters. Capturing them to some RGB paint program (or worse yet, two different RGB paint programs) and then looking at the values really has no bearing on what you want – boradcast legal. Now, for an additional thought. There are what are known as 75% bars and 100% bars. They have different values for the bars. I use exclusively 75% so I can't eleborate on the 100s. But the top white bar is actually not 100% white – the bottom one is. The top one is actually considered a 75% gray. Also, if you bar1, bar2, bar3 is a reference to the pluge pattern, it is there on the Toaster bars. If you have a monitor with blue check, bright, contrast controls, you can tune the monitor to properly reflect NTSC values. In such a situation, you turn the black level (brightness) up until all three bars can just be distiguished. Then you turn the contrast (picture) fo that each step appears about twice as bright as the the preceding one. Then you turn the brighness down until the two left hand stripes look alike. You should still be able to barely see the third stripe. At this point you are ready to set the chroma gain and phase controls for your monitor. So basically, unless you have a Waveform/Vscope and/or a properly calibrated monitor, there is no way to tell which unit is performing to standard. But I can tell you that most Toasters are dead on with a few that were a little "hot" (10 IRE black instead of 7.5). I assume the Pinnacle's are too, as they would not have gotten such favorable press in the pro video rags if they couldn't even output color bars to spec. wmc – via Autopilot!