8mm Forum: Newer Acetate focus problems

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Posted by Chip Gelmini (Member # 44) on February 22, 2006, 05:16 PM:

I have been collecting super 8 for a very long time. I have run acetate and polyester for so long, it is difficult for me to solve this new problem.

Can anyone tell me why, newer select prints of acetate with sound striping are running out of focus? The given problem....when spliced to polyester, major focus adjustments are required.

WHY?

These prints I have aquired from Steve Osborne and I believe they are from CHC in Cleethorpes.

They are:

Rupert & The Frog Song
Mr. Bean Goes to a Premiere
Chubb Chubbs
Various Dolby Stereo Snipes

Even after multi runnings and 3 Filmguard screenings I am having this problem. Any information would be greatly appreciated. The pressure springs on the front gate of the Elmo ST1200HD that I use seem to be just fine. Older acetate prints from years ago are not giving trouble.

Thanks in advance.

Chip

Posted by Adrian Winchester (Member # 248) on February 22, 2006, 06:20 PM:

I've always thought that this was liable to be a problem, if you splice the two together, because I believe polyester stock is usually thinner. So I'm more surprised that you have not found the same thing with your older acetate films.

Posted by Michael De Angelis (Member # 91) on February 22, 2006, 07:10 PM:

Chip,

As you know, there are many variables to take into consideration.

I do not have any prints from CHC, but I always need to
touch up the focus between prints.

It's not what you have failed to do with film treatment, it's
only that the stocks are different, and a slight touch up
on the focus is due between the different stocks.

Have you changed the lens on your setup?
A faster lens, will make this incident more noticeable between stocks.

Some lenses such as the Elmo 1.0 lens, has less depth of field.
It is more difficult to keep films in focus.

But it seems that the newer stock that CHC is using is
different than what you may have been accustomed to using in the past.

I have also found the longer or warmer the lamp is running will also affect the focus.

I don't know if this answers your questions, but I hope it was helpful.

Michael

Posted by Kevin Faulkner (Member # 6) on February 23, 2006, 01:22 AM:

Polyester stock is thinner than Acetate and also most poly stock had laminated stripe I believe? The films coming form Dearann and CHC have paste stripe whcich is probably thicker. The stripe is on the base of the film which sits against the fixed film gate so any variations in stripe thickness along with film thicknes will shift the focus.
This is why Noris and one or two others had the fixed part of the gate on the lens side so that the emulsion side was allways the same distance from the lens. Variations in thickness wont show up in that arrangement.
Earlier Poly and Acetate print stocks were the same thickness.
Todays Acetate stock is thinner than the earlier stocks I know that contradicts what I said at the start but the spec of film has changed over the years.

Kev.

Posted by John Clancy (Member # 49) on February 23, 2006, 05:42 AM:

Kev, the present acetate prints coming from CHC have laminated stripe applied at the lab. That is possibly what makes the stock appear thicker than acetate stock from years ago.

Posted by Kevin Faulkner (Member # 6) on February 23, 2006, 07:46 AM:

I think it is probably down to stripe thickness. Yes I forgot that Derann arent applying the stripe to CHC's prints now. Thinking about it Derann have been applying paste stripe to all their poly prints.
If the CHC laminate stripe is thicker then that would give the prob that Chip has mentioned.
Chip, it looks like you will have to stay close to those focus controls.

Kev.

Posted by Chip Gelmini (Member # 44) on February 24, 2006, 11:32 AM:

Thanks guys for your inputs. Somehow, I expected to read Kevin's final comments about this. It's just a bummer, because I run with two machines and I've taken the time to buy 3 reels of Dolby snipes, cut them up and insert at the ends of short reels and/or on the front of feature reels. Imagine a quick focus adjustment just seconds before changeover, then back again between formats and big reels!

I really like the Dolby snipes. I've been using them sort of, as feature presentation snipes. My other complaint about them is they are not stereo sound on super 8. I understand CHC does not have stereo dubbing equipment, so that's OK, but still alittle dissapointing. By the way for those of you who don't have these buggers, they are great graphics and look positively stunning in scope. You get five prints on one reel, 2 scope and 3 flat. Between formats there are duplicate graphics, but all 5 screened there are atleast several different versions. My personal favorite the very last one, flat, that has a helicopter flying through downtown, and the word Dolby is built into the theater's building design.

CG

Posted by James N. Savage 3 (Member # 83) on February 25, 2006, 11:21 AM:

Chip- I purchased the helecoptor dolby clip on another reel a few years back and had Robert Aragon re-record it to stereo- now it sounds a-m-a-z-i-n-g! Check with Robert to see if he's still re-recording.

Nick.

Posted by Mark Norton (Member # 165) on March 02, 2006, 10:23 AM:

I have this reel too.The Dolby steam train is my favourite but it is the mono sound that lets it down. I have managed to re-record the "Helecopter" one from video and this is now the business with sound comming from the surround speakers.
Does anybody know where to sorce the sound for re-recording the others? Also I seem to have the same focusing problem with these.

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