Trish and Chris have written a lot of very popular books on After Effects.

I'm on an Ubuntu box right now and can't try things but I can kind of imagine things based on this and Glenn's page about how codecs respond to the 32-bit switch.

It sounds like two possible changes go on: Gamma may be changed to 1.0 if this is the compositing gamma you've chosen, and your image may get converted to computer RGB if you render to a codec that renders that way in 32-bit mode. See Glenn's write-up here.

Let's set aside the Studio RGB to Computer RGB conversion and suppose that we're rendering DV footage to DV or to Cineform. These should stay in Studio RGB space. (is this the same as REC.601?)

Okay, so suppose you have a program on the timeline and all the cuts and transitions have been laid in, but nothing has been rendered. For testing purposes you'll render the program to a new track in the DV or Cineform codec (because these won't change from studio to computer rgb) and you'll do it three times, once in 8bit mode, once in 32-bit mode with compositing gamma of 2.222, and once in 32-bit mode with compositing gamma of 1.0.

Comparing the 4 tracks (including the original) I'd expect that all but the 1.0 gamma version would look pretty much just like each other. The one render that was done in 32-bit mode with 1.0 Gamma will look different and require a gamma correction to return it spec (this is a blind assumption on my part) but after correction you'll find that transitions look different from the other 3 examples.

This is an example where you can switch back and forth between 8 and 32-bit modes. It requires you to know how a handful of codecs will behave when rendering in 32-bit mode.

Conversions between studio and computer RGB levels is another matter and is at the root of what you might see if you render to Sony YUV in 8-bit and then 32-bit modes. In each mode I think that one encoding will match the original but the two won't match each other and this is a case where you either can't switch modes mid-project or must be very disciplined about how you do it. I'm not very clear on this but it seems like you need to know to check your renders, need to know what to look for, and need to be clear about what your preview method is going to do to the picture (for instance, will previewing over 1394 output remap the image to studio RGB?).

Rob Mack

These should stay in Studio RGB space. (is this the same as REC.601?)
Not really.

Both Rec. 601 and 709 call for 16-235 Y'CbCr levels (not RGB).
There are three differences between 601 and 709:
A- The luma co-efficients and scale factors have changed. If you use the wrong set of numbers, you will get major color inaccuracy. This should not be an issue in Vegas 8.
B- You can define the exact shade of red, green, and blue in chromaticity co-ordinates. For SD broadcasting in NTSC countries, you'd use the "SMPTE C" set of colors. For SD in PAL countries, you'd use the EBU set of colors. For modern HD (i.e. none of the dead HD formats), you'd use the Rec. 709 set of colors.
In general, few systems account for this and they get away with it.
C- The transfer functions are different between Rec. 601 and Rec. 709.
In general, few systems account for this and they get away with it.

Many high-end systems will account for A but not B and C. e.g. Teranex standards conversion boxes can't do C. It is usually not set to handle B.

Back to talking about Vegas...

In the compositing gamma of 1.000, your values will go...

8 bit Integer (gamma corrected) --> float (gamma corrected) --> float (linear light) --> image processing (filters before pan crop, pan crop, filters after pan crop, compositing) --> float (gamma corrected) --> 8 bit integer.

You go to linear light and back. *With the exception of 8-bit filters and 8-bit transitions.

2-
Don't worry, even I don't get it. (How you're supposed to work in Vegas.)

The point to my post was actually to keep it real simple, I think a lot of us are very confused over the very basics, throwing all the high level issues into the mix is probably loosing a lot of people, without a simple mental model of the very basic stuff the rest is hard to fathom. I especially liked the most basic example in the article, the grey card where 50 = 18. If you don't get what that means the rest is just technobabble of the kind I find has most people dozing off. The technical stuff gets me interested but I don't think I'm like most of the people here.

If I can elaborate on that very simple example.

Take three cards, black, grey, white. The grey card is that Kodak 18% reflectance card (we all have one in our kit bag?).
Light each one with the same light, say a 100W incandescant on each. The grey card looks like it's half way between the white card and the black card. Now suppose we want to make the grey card look as bright as the white card, well as it's 1/2 as bright simple logic says shine another 100W light on it and it should look the same. Thing is it doesn't, not by a long way. Reason is our vision isn't linear, what we see as 50% of the light from the white card is only 18%, to make the grey card as bright as the white card we'd need more like a 500W light.
But this isn't all bad news, our video cameras can make very good use of this 'defect' in our vision by recording the image much the same way as our eyes see it, that's in simple terms why our 18% card reads 50% on our scopes too.
So what's the problem, well in the real world, the ones our eyes don't see right, light adds linearly, we saw that when we tried to make our grey card look like our white card. So in the real world all the light adds very simply and we see the result in our special non linear way. However what our camera has recorded is like our eyes, non linear. When we try to add two images togthere we're adding non linear light to non linear light, oops, it doesn't work like the real world does.

So in very simple terms, the linear light model is attempting to undo what a camera did, get things back into the real world so we can do things as they happen in the real world, so well, the results look real. We still need to put them back into the way out eyes / cameras work when we've finished doing things with them like compositing (compositing is adding light) or dissolves, if nothing else our monitors aren't linear either and it's kind of funky seeing a linear light image on them. The only exception, when you wouldn't put them back into a non linear world, is if you were outputting to a linear light system but that's pretty unlikely generally.

Now the above is very simplistic, I haven't mentioned color or any of the other great complications, like gamma or S curves or gamut. But if I've explained the above fundamentaly correctly (I hope?) then you've got a mental model to pin all the other stuff onto. From my experience with my schooling, it's taken me most of the rest of my life to grasp the simple models that underpin all the stuff I managed to learn and spew out in exams without a shred of understanding.

Bob.

Glenn! Thank you: Don't worry, even I don't get it. (How you're supposed to work in Vegas.)

To date, I think, apart from your examples inspring me to "have a go", we are the ONLY people who have actually come out with pictures of what we have done!! Your "church" and stuff just bowled me over . . I've just followed your tutorial AND applied it to the "Ducks" too - woah!

Y'know what? It would be real nice, for others commenting, to ALSO dig out some work, apply how THEY have use it and SHOW us too!! I want to know HOW to use it! Where to use it? What to use it on? Where OTHER NLEs use and for WHAT visual reasons!! And in PICTURES!!

Glenn thank you. Your one comment simple, as to how (?) to use, within Vegas has cleared up my vision on this. Perhaps others might be "tempted" to come outtta the shadows and show us too? Yeah?

Cheers guy . .

Grazie

I'm confused,
your ducks are showing the difference between 8 bit and 32 bit CC, were you also using linear light?

Where should we use linear light in Vegas?
Compositing, Glenn's example's with the use of glow are a good example, the effect on dissolves in the article I posted originally are a good example although as Glenn says there's already ways to do this in Vegas.

What I'm really hoping it will fix is compositing DJ motion elements with alpha channels, I and others have had issues with this in V7. Trust me unless others beat me to it I'll post some examples as soon as I can. I'm with you here Grazie, I'm kind of amazed no one has tried this yet and the title of the thing in Vegas does give a pretty solid hint as to where to use it.
I think Glenn's already covered how it could be used in Vegas with compositing, do your comps in a linear light project and nest that in a regular project. The linear light project will take care of all the conversions that I mentioned above, the output from the nested veg should match back into the master project correctly.

Both 8 and 32 have the SAME CC and CCurves and I used Linear light.

I DID experiment with the Video 32bit, but it didn't do anything for me. I really must pay more attention to what I "must" and "must not" do. Anyways, Linear gave me results I like.

I also followed Glenn's Tute on Linear, for that glowing look - amazing! I just now tried it on the Ducks.

Using the 32Linear, the Green water looks great and the reeds are graphically set apart from the rest too. If I am incorrect in doing this, but I like what I am getting - what do I do next?

Grazie

Someone correct me if I'm wrong here but to use LL you must be in 32 bit, no?

Downloaded trial, man that new icon and splash screen must upset the audio guys.

Installed lastest QT viruses.

Rendering DJ explosion like revealer, let's see how it all flies together.

Bob.

PS Like the new audio mixer.

BOB!!!! Yes yes yes . .

Look.

1- I did a 8bit of the event which had CC and CCurves

2- I did a 32bit of the event which had ( the same as above)CC and CCurves

Yah can't GET LL on 8bit! I never SAID I did LL on 8bit. Where DID I say I did LL on 8bit??? If you click on 8bit the darn thing for LL is greyed out anyway! PERIOD!

Even THIS thicko Englishman knows I can't use something if it is greyed out - yeah?

. .I need to lie down . .quickly . .

Grazie