Film-Tech Forum ARCHIVE: Purple Line On Screen?

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Posted by John Westlund (Member # 913) on 10-22-2001, 11:58 PM:

There is a purple line on the left side of the screen. The line seems to come and go and seems to be more visible when the scene is dark. The projector is a Century SA. Is there anything you guys know that I can do about this problem? Thanks
John

Posted by Brad Miller (Member # 2) on 10-23-2001, 01:20 AM:

Your aperture plate is opened up past the 825 line. Contact your tech to see about having him cut a new plate. I don't know the exact reasoning as to *why* this is, but I'll betcha Mr.Pytlak can tell us.

Posted by Darryl Spicer (Member # 711) on 10-23-2001, 01:21 AM:

Sounds like you are seeing the edge between the picture and the soundtrack information...Check your aperture plate or projector alighnment could be slightly off causing junk ti hit the screen instead of the masking.....

Posted by Rick McCluney (Member # 642) on 10-23-2001, 01:24 AM:

Sounds like the aperture plate may not be pushed all the way in.

Rick

Posted by Randy Stankey (Member # 64) on 10-23-2001, 02:12 AM:

I vote that the aperture plate isn't aligned right. Chances are you can wiggle it back into place.

If that doesn't work, pull it completely out of the projector while it's running. Look and see if the picture is lined up on the screen correctly. That part of the soundtrack you are talking about should be completely off the screen and showing only on the black part of the masking. It it's intruding onto the screen, it's not your aperture plate that's wrong but your lens adjustment. If you run some film through the projector (while there are no customers) you can eyeball the thing back into alignment well enough to hold you over until your technician can come out and run some RP -40 test film to do the job right. Test film is the only way to do the job right. Eyeballing is only meant to be a "Band-Aid" measure.

Posted by Brad Miller (Member # 2) on 10-23-2001, 03:01 AM:

Ah yes, silly of me for not thinking of that most obvious probable cause. Cast me as a 3rd vote for the aperture not being slid in all the way.

If that's not it, then check the eccentric lens or turret alignment (the aperture would still be overcut if that was the case). Finally, go for a new aperture.

Posted by Joe Redifer (Member # 3) on 10-23-2001, 04:18 AM:

I'm guessing that this has something to do with the aperture plate.

Posted by Scott Norwood (Member # 30) on 10-23-2001, 05:53 AM:

Possible temporary fix: file down (ever so slightly) the edge of the aperture plate farthest away from the operator (the outside edge, not the edge within the picture area). This will let you push the aperture plate in slightly farther than you can now and will cause it to cover the blue line on the soundtrack edge. Before doing this, just make sure that the non-soundtrack-edge of the plate is not also overcut.

Before doing this, make sure that the problem occurs with more than just one print. It could be tha tyou have a print (or, more likely, a reel) with an improperly applicated soundtrack.

Posted by Gordon McLeod (Member # 33) on 10-23-2001, 09:04 AM:

It is also possible since it comes and goes they are seeing the effect of the soundtrack applicant that has bled over the soundtrack and into the pix area. When the industry finally switchs to cyan tracks that problem will be a thing of the past

Posted by Joe Beres (Member # 678) on 10-23-2001, 09:12 AM:

You are all potentially correct, but Gordon has a good point. I actually have some perfectly machine cut plates that work better than any of the hand-filed plates I've used over the years. But, every once in a while, I will see the effect that John described. In these rare occurences, I just try to move the screen mask just right so that it covers the left edge of the screen just a hair more than usual. It makes annoying (almost pulsating) purple edge a little less noticeable.

Posted by John Pytlak (Member # 331) on 10-23-2001, 10:42 AM:

I suspect either the aperture plate is not seating properly, or was not filed correctly. Before making any changes, check the projected image area using the SMPTE Projector Alignment Film 35-PA (RP 40). The proper width for both "flat" and "scope" today is the 0.825 inch width markings. Seeing the dark blue or magenta stripe at the left edge of the image means you are seeing the analog/DTS soundtrack area.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by Gordon McLeod (Member # 33) on 10-23-2001, 12:24 PM:

839 is still supposed to be clear of any problems as many theatres still are set for that size

Posted by Randy Stankey (Member # 64) on 10-23-2001, 12:26 PM:

The left-right (inboard/outboard) alignment of the aperture plate on a Century SA is regulated by an eccentric stop. Modifying the plate would likely prove useless.

The reason I mention that the lens alignment (eccentric adjustment) might be screwed up is because on turret projectors, people have a have this habit of grabbing hold of the lens in order to move the turret by hand. (There are plenty of times when you have to tweek the turrets on those centurys.) After a few times of doing that, the lenses and their adjustments often get out of whack. The old Simplex TU-2000 turrets are the same way.

I spend a lot of my time aligning things that are messed up in that way. Once I get it pounded into peoples' heads that they shouldn't use the lens as a handle, I spend a lot less time realigning things in that particular theatre.

Posted by Scott Norwood (Member # 30) on 10-23-2001, 01:26 PM:

I should mention that I was assuming that the original poster had a non-turret Century. (Actually, I've never seen a turret-model Century anywhere except in photographs...they must not be very common.)

Posted by John Westlund (Member # 913) on 10-23-2001, 01:41 PM:

Scott is right. The projector does not have a turret. I will try the things you told me. I think the aperture might not be fitting all the way in. Thanks. John

Posted by John Wilson (Member # 269) on 10-23-2001, 10:38 PM:

This is a problem we are currently dealing with here. As you can see there is a fair amount of applicator bleed on this image. You may also be able to see the fact that the image is printed fractionally 'down' on the print, resulting in the image on screen looking slightly out of frame.

Now here's how it should look...

On the Zoolander trailer, you can actually see the boom mike in some of the shots as a result. The lab has had it brought to their attention and are looking into it. (And trying to convince the distributors I was not crazy was almost impossible as comments like 'The lab has such strict quality control measures' and 'Why is it then that YOU are the only one who is having problems with it'? almost made me kill the phone)

It appears I wasn't the only one that was having the problem...I was just the only one that noticed it.

Sad, isn't it?

--------------

"It's not the years honey, it's the mileage" - Indiana Jones.

Posted by John Pytlak (Member # 331) on 10-24-2001, 08:00 AM:

John Wilson --

The white line to the far right of the image on your top example may indicate that the rating tag printing negative came from a different source, perhaps with additional stages of printing that may have shifted the image. So the problem may be in the printing negative supplied to the lab.

Standard SMPTE 111 specifies that the inside edge of the soundtrack printed area (dimension "D") should be 0.308 +/- 0.002 inches (7.92 +/- 0.05mm) from the reference edge of the film. Standard SMPTE 195 specifies the left edge of the projectable image area (picture) should be a minimum of 0.324 inches (8.23mm) from the reference edge of the film.

SMPTE Recommended Practice RP 115 specifies that the Control and Data Record (DTS time code) is printed on a centerline of 0.297 +/- 0.001 inches (7.54 +/- 0.03mm) from the reference edge of the print.

Posted by Michael Barry (Member # 237) on 10-24-2001, 08:51 AM:

There were a whole run of trailers, like John mentioned, that were problematic in this way. At the other theatre I work at (only until November 7th!) there are three of those trailers in stock ('Riding In Cars With Boys', 'From Hell' and 'Zoolander') and those problems are on these too, but that theatre isn't running those trailers yet...the ones we are running are from other print runs and/or other labs, so that problem hasn't been an issue there.

Sad indeed, that no-one else had picked it up, and even worse is the attitude that 'the lab can't be wrong, only the projectionist could be'. I loathe that approach - the assumption that because one is a projectionist, that one cannot know what one is talking about. Absolutely appalling attitude on behalf of the distributors in question...shame on them!

Posted by John Pytlak (Member # 331) on 10-24-2001, 09:14 AM:

The image area dimensions and tolerances are documented by the SMPTE standards and recommended practices. Those dimensions can be measured directly off the prints to determine if they meet the standards. If they don't, the mistake should be corrected. As I noted, the problem could be upstream of the lab in this case.

Posted by John Wilson (Member # 269) on 10-24-2001, 09:40 AM:

Hi John

I have been contacted by two distributors today and both inform me the prints I sent back to them do not match the results on their original answer prints of their trailers.

The lab in question has admitted there has been a problem and are trying to find out where it all went wrong. Interestingly, I have two trailers of Zoolander...one is fine, the other is not.

Also, tonight I made up our new print of 'Don't Say A Word' which has an attached (printed in) scope trailer for Fellowship Of The Ring. This trailer is printed down and the feature is not.

I stress I'm not trying to lay blame at anyone...I just want the problem to be fixed and move on.

Posted by John Pytlak (Member # 331) on 10-24-2001, 01:01 PM:

Gordon said: "839 is still supposed to be clear of any problems as many theatres still are set for that size".

Although the current SMPTE standards would hopefully preclude extraneous material being printed along the right hand edge of the image, the 0.838 inch image width for "Scope" was changed to 0.825 inches in August 1993. Here is what I found, as published on Marty Hart's American Widescreen Museum:
http://www.widescreenmuseum.com/widescreen/apertures.htm

"From 1957 through today, there have been a number of small changes to the anamorphic projector aperture recommended standards. John P. Pytlak of Eastman Kodak dug through countless back issues of the SMPTE Journal in order to provide the following chronology of the changes to the standards:

The March 1957 SMPTE Journal has PH22.104-1957, the standard for 2.55:1 anamorphic (no optical track), with an aperture size of 0.912 X 0.715 inches. Notice of withdrawal of this standard was in the January 1964 Journal.

The December 1957 SMPTE Journal has PH22.106-1957 for 2.35:1 anamorphic, with an aperture of 0.839 X 0.715 inches. It was unchanged in the September 1964 Journal. The November 1965 SMPTE Journal published PH22.106-1965 still with the 0.839 X 0.715 aperture size.

In the September 1970 SMPTE Journal, a new draft of PH22.106 was proposed, with an aperture size of 0.838 X 0.700 inches, to minimize the flashes at splices. This was republished as standard PH22.106-1971 in the October 1971 issue.

In the June 1976 SMPTE Journal, the two (flat and scope) projectable image area standards (PH22.58 and PH22.106) were consolidated into one standard and renamed PH22.195. The publication of PH22.195-1984 in the October 1984 Journal still had the scope area as 0.700 X 0.838 inches.

The June 1992 SMPTE Journal published a proposed revision, with a scope area of 0.690 X 0.825 inches. In August 1993, the standard was published as SMPTE 195-1993, with the current area of 0.690 X 0.825 inches. So August 1993 is when the two formats became the same width of 0.825 inches."

The current SMPTE 195 "scope" projectable image area of 0.825 x 0.690 inches provides a bit more "margin for error" in not seeing the DTS time code, soundtrack application bleeding, or negative splice lines on the screen. IMHO, the screen masking for scope should be brought in to the 0.825 lines to reflect the current standard, and not left at the old 0.838 inch image width.

Posted by Gordon McLeod (Member # 33) on 10-24-2001, 08:19 PM:

That makes an assumption that a theatre will have both top and side movable masking or being willing to fork out for new lens
I have several theatres that spent bucks replaceing old B&L's with Isco's just before the "standard chnaged" and don't feel it should of changed. The only reason for the change was to allow for sloppier lab work

Last week I screened a old and shrunken 4 track mag print with the full 700 top height and there was not one negative frame line splice flash. Yet today with a 690 plate i regularly see flashes at the top and bottom on release prints

Posted by John Pytlak (Member # 331) on 10-24-2001, 08:45 PM:

The original "CinemaScope" cement splicers used for splicing the camera negative had a very narrow overlap, so the splices were not very reliable and sometimes broke. Over time, the negative cutters started using splicers with more overlap so the splices would be more reliable and not break in the printer, but the splices were wider and more likely to be seen. So the original projectable height of 0.715 moved to 0.700 and finally 0.690 inches.

Another way to "hide" the negative splices is "checkerboard" cutting, putting alternate scenes on two separate rolls (A/B roll printing) with the negative splices falling in black leader with a printer "zero cut":
ACVL Handbook Negative Cutting Techniques

Posted by Gordon McLeod (Member # 33) on 10-24-2001, 10:01 PM:

Bottom line still is the standard was not a benfit to the exhibition indusrty only the laboratories. If lower printer speed was maintained the issue of negative splice strength would not have been an issue. And as an aside since release prints are printed from internegs and they should be generated on slow speed printers this should not have been a problem

Posted by John Pytlak (Member # 331) on 10-24-2001, 10:04 PM:

Just describing how we got to where we are, as I understand it. The original CinemaScope narrow negative splices just weren't as reliable, so the standard was modified to reflect practical experience.