Is HD 720p similar to SD?

[Mike Truly]

I know the resolutions are different.

What I'm wondering is, when I create a project in SD 4x3 and the NX hardware settings are set to output setup Betacam 7.5, the output on my HD monitor looks one way.

But when I change the settings of the same project to HD 720p and then look at the HD monitor, it looks darker. Maybe I'm imagining things

For example, on the SD project I have a YUV CC on clips that boosts the Y a little bit (basically a gamma correction) and the image looks fine on the monitor.

But when the project is converted to HD 720p settings, the image looks darker on the monitor and I have to adjust the CC more.

Shouldn't the images look exactly the same on the monitor in these SD and HD projects? (I'll have to do some more testing).

Thanks!

[GrassValley_KH]

Bear in mind that there is a different colourspace in use when going from SD to HD - 601 to 709.

[Mike Truly]

OK, I did a little more testing and there definitely is a difference.

I put some color bars on both the SD and HD timelines.

On the the production monitor is adjusted to the SD colorbars on the timeline. Specifically, the brightness is adjusted so the small, vertical gray bar in the lower right of the colorbar is just above black... you can just faintly see it.

Now when I load the HD project with some color bars on the timeline, the faint gray vertical bar is gone... it's completely black and blends in with the black background... it's darker than the same color bars shown in the SD project.

Kenneally, I'm not sure I'm understanding you. My animations are created from the same RGB TGA frames and then an HQ AVI is created and that HQ file is used on the Edius projects. The only difference is the resolution of the SD file vs the HD file. Is there something within Edius that physically changes the output signal when these two different projects are used?

If so, that's fine, but I need to know about it and understand it because it will require that I tweak the HD version differently than I tweak the SD version.

Thanks!