The Strange Affair of the Darkening Preview

Hi

I have After Effects 6.5, standard edition (version 6.5.0.97 on the "About" screen). I am very new to this and haven't done anything really complex or involved yet, but I have been running into an issue concerning previewing transparencies and objects with gradient edges.

With some transparencies or objects with a gradient edge, any manipulation of the timeline or the comp window will cause the image to become progressively darker each time the preview is played back. Plus the background color will switch to black after the first pass no matter what it is set to in the composition menu. You can get the transparency back by turning off and on the video switch in the timeline (the eye icon), but it will just exhibit the same darkening behavior the next preview. This happens in both RAM preview (number pad 0) and normal mode (space bar).

Certain graphics suffer. For example on a 50's style flying saucer .tif with a clear dome the streaks and gradients that make up the dome will disappear with repeated preview passes. Several mattes and masks suffer as well. Pretty much anything with a gradient edge is bound to darken or disappear during previews.

This doesn't happen with all transparencies but I noticed it seemed to happen every time I used a Luma matte but Alpha mattes didn't seem to be effected.

Motion Blur disappears over time. Again, first time through its fine, 2nd time, less blur, until repeated passes the blur disappears all together. Open GL is, of course, off during this.

I do know about the issues with open GL and I also am aware of the various preview options. I have tried them all with and without GL (actually kept notes) and the darkening problem persisted no matter what the preview mode was set at.

The problem showed up in example projects from both tutorial books I'm using as well as the projects I assembled from scratch.

My computer is an older PC workstation, assembled by Safe Harbor Computers. After Effects was installed by Safe Harbor at purchase. The computer is a "Tsunami" edition, with two Pentium 4, 3.4 GHz processors, 2 GB RAM, NVIDIA Quadro FX 540 graphics card, Matrox video DV/MPEG Codec driver, RTX100 Flex30 Accelerator, RxLo and a video bus. No Modem.

Interestingly this darkening doesn't happen on my laptop, a two year old Dell XPS. I can do my tutorials on that I quess, but it doesn't have nearly enough oomph for when I start using DVD quality video. I really need the tower.

Thank you for your help in this problem.

-- Jack Olcott
SlimJack@aol.com

PS: CreativeCow looks to be one heck of a website. Wish I'd discovered it earlier!