I think I've noticed the same thing, though I was working with time-altered QT animations with an alpha channel, and the result was that the color shifted. I found I could work around the problem by nesting the clip first, and then applying the speed change to the nest. For some reason, the color shifting didn't happen then; try that and see if it helps your situation.
I haven't had a chance to do much testing, but I think this might be a problem that was introduced with the 4.2 update--I had no problems of this sort with 4.1.
Thanks for your reply.
If by nested you mean that the clip is within another sequence that has been added to the parent sequence, I have already done this and it does not solve the problem.
I have played a bit more with the QT export from Premiere and found that the problem changes depending on the video codec. Graphics and H264 are the same - speed altered clips go dark. DVCPRO-PAL and DVCPRO50-PAL make the entire video dark. DV-PAL squashes the video (since you can't change dimensions).
There is no problem with colour on screen shifting; it is just that the affected sections go darker - as if viewed with a transparent black screen over them.
It means that there is no way to get QT video out of Premiere - how odd!
Ah, now I understand--I guess I thought you were talking about using QT clips in your timeline, not just exporting to a QuickTime file. In that regard, though, I have noticed that trying to export to QT files (with certain codecs) does result in a noticeable darkening. I couldn't figure out how to work around that particular problem--at least with Premiere alone. What I ended up doing was exporting an uncompressed file from Premiere (AVI or MOV should work), and then used MPEG Streamclip to create a compressed QT in whatever flavor I needed. I don't have it, but QuickTime Pro would probably give the same capability; I like MPEG Streamclip because it's free.
If you check videocopilot.net he mentions how to work around this exact problem. I don't remember exactly where to find the info on his site but he does talk about it somewhere. If I remember correctly there is a setting in Quicktime he changed to make his exports look the way they are supposed to.
Thanks for your reply Colin.
Since I'm on a Mac I can only export as MOV (not AVI). I've just tried various MOV codecs including video, uncompressed 8-bit and uncompressed 10-bit. The first two came out the same (speed altered clips dark) and the last couldn't be played by Quicktime or VLC.
I do have MPEG Streamclip and would be happy to take this approach, but currently there seems to be no way to get high quality video out of Premiere.
The best solution for now seems to be to export as F4v (which doesn't have the dimming problem) at maximum bitrate and then convert to Quicktime using AMC. Seems odd to start with a compressed format as your master though...?
I've never used PPro on a Mac, so I guess I didn't realize there was no AVI export option on the Mac version (there is QT export on a PC, so I guess I just assumed... but you know what happens then...).
Another possibility would be an image sequence export, for example TIFF or TGA. I know QT Pro will open image sequences, but I'm not sure if MPEG Streamclip will or not--never tried it. Could be an option, though...
EDIT: Indeed, MPEG Streamclip will open image sequences. Just use the normal "open" function, and then select all of the image files. The program will turn them into a pseudo-movie, with each image as a frame, and then allow you to export out to any format of your choosing.