Hi. I can chromakey using a talent videod in front of a green screen ok using CS5 premiere pro. But I can't manage to use a Track matte in the same programme I have scoured all the references to this method in adobe official manuals and youtube presentations, but I can't follow them. They all seem to assume that I know everything, which is far from the truth. What I want to do for example:- I have a shot of a house exterior in semi darkness and this house has several windows on show but none of them lit. I would like to show that one window is lit to convey occupancy. Can anyone please tell me step by step how to achieve this. I know about garbage points but having framed one of the windows that's as far as I get. All advice will be most welcome.

Here's a start: Premiere Pro CS6 Techniques: 97 Track Matte Key - YouTube

Google is your friend, there are a number of tutorials available on the web, it's maybe more complicated than practical to explain in a couple of paragraphs. You will want to create your matte to match the window, matte the illuminated image you want to paste in (if I understand you correctly) then move the matte and overlay image as needed. Sometimes more easily done in After Effects, but you can do it in PPro.

Battle. Thanks for your input but I am using CS5 and all these mattes available in CS6 are not with CS5. At my age (87) I find these tutorials very confusing and they don't tell the beginner the obvious. Anyway I don't want to use green screen objects as I already know how to use them. It's using track mattes to alter a still scene that I want to know about.

Roy, I have done track mattes on CS4, so I think the same, or at least a set of, these tools are there. Perhaps if you look on-line at the Adobe CS5 help files, you'll find a concise explanation. Best wishes!

Put your still on track one.
Put the same still on track two (superimposed)
Open the titler and draw a white shape over the window that you want to lit.
Put this shape in track three.
Add the Track Matte effect to track two and set it to track three.
Next bit is trial and error for which effect.
add e.g. Brightness/contrast to track two and turn up the brightness.

BATTLE. I thought you might like to know that I have successfully used the track matte to alter a part of a still clip. A poster on the UK> IAC forum gave me instructions in plain English and it worked perfect at my first attempt. It involved using the titler to put a white square over the part of the still I wanted to change. Thanks for your input.

ANN. Thank you for your input. One question:- Is it possible to put a dissolve between the altered clip and the next unaltered clip on the timeline. I've tried the normal method of puting a dissolve between them and nothing happens.

In order to put a cross dissolve between two clips they need to be trimmed back to get handles.
You need handles to make a transition.
Adobe Premiere Pro Help | Transition overview: applying transitions (http://helpx.adobe.com/premiere-pro/using/transition-overview-applying-transitions.html)

regarding dissolve problem between a clip being altered by track matte and a normal clip on timeline. I can tell you that 24 hours later with all conditions being exactly the same as previous and using the same procedure to install a dissolve- It worked. Queer things Computers.