My problem is that I don't know what's the best way to leave some black leader and still know where the frame line is. I noticed that for at the beginning, they scratch part of the emulsion to let you know but there is no such line at the tail.
What is the best method for this?
Thanks
Richard
At the end, at least on US trailers, there are a variety of ways to mark where to cut. Some use four circles one the edge of the last frame:
oooo
I usually cut right before that. Others use lines on the frames (numbers only represent sprockets, not film markings):
1234
l l
And still others just seem to end without warning. Well, not totaly without warning. These trailers-Disney and Dreamworks-have as they're only clue a discoloered frame. At the very end of the black, their will be one frame that is orangish. Cut as close to that as you can.
If anyone with more experience see's a problem with anything I said, tell me, always willing to learn. However this seems to give me just the right amount of black between trailers.
Sorry, but I can't endorse this practice. Using "Liquid Paper" as a marking ink on film (even leader) is not good practice, as it tends to leave flaky debris on the film and projector.
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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com

However, if the print is a multi track print, you should put little dots in between the non-soundtrack sprocket holes so as not to disturb the next theater which may need one of those digital tracks.
I don't think that John W. was talking about using Liquid paper to mark anything onto the film itself. I have seen many of these makeshift framing aids in many a theatre's bench drawer, its a 16 tooth sprocket with a white mark painted on it every 4 teeth and across its width, (what John W. was trying to explain that he wanted to do with the Liquid Paper) then attached to a wooden or plastic handle with a screw.... Most of the ones I have seen were attached to a carbon arc hand dowser handle.
Aaron
1. |oooo - Frame line followed by 4 circles. Cut right after 4 circles.
2. ^----^---- - Usually there are about 6 - 10 frames of the ^----. Cut right before the sequence starts.
3. 2 frames brown, clear, 1 frame brown. Cut on the frame line of the brown frame. Now use clear leader or turn trailer around in splicer and lay a full length from blade to 2? sprockets short of edge. This will take off 8 frames.
I know there are more, but these are the common ones.
Not the film...
...on the sprocket. 
Liquid paper on the film...blech!!!
John...I'm surprised you would think I was capable of such a crime.
PS: Thanks for coming to my aid, Aaron.
I thought you were putting a load of Liquid Paper onto the sprocket every four teeth, and then running film on it to transfer the still wet Liquid Paper to the film to mark the film. Why are you using Liquid Paper to mark the sprocket, rather than something more permanent like paint or a scribed mark? ------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com

John Pytlak, any chance of pitching the idea of standardizing the leaders used for trailers? New Line's are the best.
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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com

John, can you pitch to them to get completely rid of that "tv cue mark" just before the green band starts? Also, I would like to see a total elimination of those "clear edge marks" that the Deluxe lab is so proud of.
Could you send me actual trailers with the undesirable flare on the black head leader, and with the unnecessary TV cues? Also, examples of bad packaging. Showing actual film examples to these committees is much more effective than describing them, or just showing photos.
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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
I have another way to breakdown an entire center ring. We take a center ring (ring and all) and mount it onto a large split reel. (These had to be drilled for the center ring pins) and then rewind the trailers onto cores using the buildup table. This way there is no chance of the film becoming tangled and ending up on the floor. Of course if we are just removing a single trailer from a preshow you have to use the method Brad described.
I also know another way of breaking down entire center rings using only the MUT.

I just need the trailers with examples of poor leader/packaging practice by the end of September, in plenty of time to show to the Inter-Society and SMPTE committees at ShowEast in October.
I will also show copies of the trailer handling/splicing "Tips" now on Film-Tech.
------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com