As Joe points out, most Effects can be Keyframed over time, though not all. Usually, there is one that CAN be Keyframed, that will accomplish what you want, and then often workarounds to using others (usually a Razor Cut, adjustment in one of those Effects w/ a Cross-Dissolve applied at the Cut), but using one with Keyframe capabilities will nearly always be the better choices.
Knowing which Effect you are applying, will be helpful, as someone should be able to offer a workaround, or the suggestion of a different Effect w/ settings to accomplish the same, or very similar thing.
The light is very bright in some places and some other places are too dark. I found a way to change the lighting but it's not gradual. It's very brief and it creates a kind of "flash". I would like to know if there is a way to change the lighting gradually. i use Premiere pro CS5.
Apply an effect that you can keyframe. IIRC, there's a luma corrector effect. Find that and drag it to a clip on your timeline that you want to correct.
In the luma corrector, there's a gain control, again IIRC (I haven't had to do this in awhile so it's not really fresh in my mind). Use keyframing to pick what level of gain you want at certain points in the clip -- and PPro will ramp the gain up and down for you between keyframe points. For example, if you like the light at the start, make that a gain of 1.0. Then toward the middle it's gotten darker, so you have to make that gain 1.1 to make it match the first keyframe. Then the end of the clip it's started to get lighter again, but not at the same level as the beginning, so you have to set it to 1.05. Now when you play back, you'll see the correction applied in a linear fashion. You may find that you have to apply more keyframes, and that you have to adjust the value of the keyframes up and down. It's an iterative process, and it has a learning curve. You'll get better at it if you do more of it. But in the end, you can make the clip play with fairly even "light" as it were.
But what this should really teach you is to control your lighting so that you don't have to do this again. Because it is a PITA. And it can usually be avoided, and should be.
I'm sorry for the delay and i want to thank you for your answers. Right now at work i am much over my head and don't have time to test what you showed me. I will do that at the beginning of next week. I thought important to tell you this by respect for the time you took to help me!