"Web first grading" Conversion to Broadcast as a "budget solution"?

[qwerty123]

As we all know, there is little in the way one can do to in the way of a “budget” solution for a true broadcast monitor (the cheapest, “close-enough” solution seems to be connecting a calibrated hdtv via some card or breakout box and your stuck with blackmagic if you want to use Resolve). Of course, none of this is necessary if all you are doing is web work or if you don't care much about how your grade on your computer monitor translates to DVD or video broadcast.

But, I've always wondered about the following “reverse grade procedure”: if we know the ways in which the video Rec 709 space differs from the RGB color space of a properly calibrated computer monitor, then how come the following isn't possible as a cheap solution for those who want accurate grades both for web and dvd / video / hd-cam distribution?

Step 1. Color grade movie on an RGB color accurate (IPS) computer monitor.

Step 2. Apply the universal adjustments to contrast and color necessary to make the movie played in rec 709 grade look very close to (exactly?) like the grade on the RGB monitor

Of course, we'd need to know what are the proper adjustments. But once you know what they are, you can just apply them to any future grade.
I'm sure I'm missing something, but I'd like to be illuminated on this issue!

[Razz16mm]

sRGB and REC709 are pretty much the same color space and gamut except that 8 bit digital reference black is 16 and 100% white is 235 for REC709. 0 and 255 are illegal values reserved for sync. The ranges from 1-16 and 235-254 are reserved for peak over or undershoot during broadcast. Kind of a peak buffer zone. Some NLE's have a filter you can apply that automatically adapts signal values to the legal range.

If your computer video card has DVI or HDMI out ports for a second monitor, a major brand consumer LCD or plasma TV makes a superior reference monitor compared to any low cost computer monitor if reasonably well calibrated to a set of SMPTE color bars. Their panels and circuitry are optimized for HD video instead of computer graphics. In most cases your web videos would probably look better and more consistent too, especially if you do like a lower contrast "film" look with unclipped whites and blacks.

[Postmaster]

Isn't 709 a different gamma? At least my Dreamcolor says so, when I switch between sRGB and 709.

Frank

[Razz16mm]

Isn't 709 a different gamma? At least my Dreamcolor says so, when I switch between sRGB and 709.

Frank

Yes, sRGB is 2.2. As of this year REC709 uses 2.4 for reference gamma. Not a huge difference.

[qwerty123]

Hmmm... If things are so close, then why is there this strong insistance on having $2,500 and up broadcast monitors?

That's not sarcasm. I'm genuinely curious. I've read a bunch of stuff, but I haven't yet found a clear explanation for this.

[KINOKS]

On such a monitor you really get to see the real picture. And that is basically it. All the bonuses are surrounding this fact. Plus with some
you get scopes, like waveform or vectorscope.