Adhesive holders

[Drew Wiley]

You know the saying, Bob... If you want something done right, ya gotta do it yourself! Nearly all my lab gear is either personally made or somehow modified. Lenses would be the exception. Gosh I had to pull teeth and twist arms with a lot of companies to not only get direct access to engineers, but more importantly, the right engineers, not too long ago when I was still a distributor, at least in terms of the person in charge as a buyer. The last ten years I was doing mostly contractor tools. Festool engineers were a dream to work with, Makita depended on the division - they had both aerospace-level engineers and sheer idiots, depending on whether the intended market was industrial or home-center. Bosch was undergoing an internal war between its traditional professional division and the bright-eyed, bushy-tailed geeks and bean counters who wanted to junkify everything. So-called US companies had already become blatant outsourcers and didn't give a damn about anything except the CEO's next golden parachute. Glad it has ended and I can now concentrate on my own toys.

[Tim V]

I'm reviving this thread because I'm going to give this a go. I've paid for an 8x10" holder to "sacrifice" and have placed an order for the 928 tape. Fingers crossed it's actually available here in New Zealand...

The picture here of the actual Sinar holder seems to have a square shaped sheet of adhesive, with quite a bit of non-adhesive area at each end. To those who have done this modification themselves on an older holder, how much surface area do you cover?

Also, has anyone tried cutting away just one of the film guides? I'm guessing leaving one guide in place might be a good way to help line up the film in the dark against one edge, aiding in dropping the film flat? Having not handled the adhesive tape yet and not nowing exactly how sticky it is, I'm a little skeptical of it's ability to keep a large sheet of film in place. I strongly suspect however that this concern is unfounded else others wouldn't bother doing this modification in the first place.

Lastly, after laying the film in place, do you apply any pressure to make sure it's stuck? Do you wear powder free nitrate surgical gloves or anything? Any tips for this crucial part of the process on how to make sure it's not only flat, but the emultion remains pristine?

I'm wanting to use this adhesive back to keep a sheet absolutely flat for ultra long exposures (12 hours plus) as have experienced MAJOR popping in tests, leading to very weird (if sometimes kind of cool) ghosting effects.

[Tin Can]

Makes sense to me Bob.

I have checked GG placement on many cameras and holders.

Please consider revealing the Zero GG manufacturer, the resulting furor may be interesting.

Yet not the last word in ' best' or finest engineering as you imply from your Kodak Quick Load comments.

GG specs are in a range for very good reasons. Stack up differences are what matter.

Drew,

Several years ago Kodak engineers cameto my office to measure the gg placement on current, at that time, Linhof cameras.
On that trip they also went to Toyo at MAC and Sinar.

Somewhat after that trip they called to tell me that they were coming out with something called Readyload film and needed to know the gg placement for cameras commonly available, they made other trips to visit other manufacturers and distributors. They found that one camera had, what they called, a 0 gg placement no, it wasn’t Linhof, and that since film sags they needed to determine the average gg placement on current cameras.

When you use an adhesive or vacuum back the film can not sag and your gg may need to be re-positioned.

And yes, they did tell me which camera had a 0 gg but that info I will not pass on.

[Bob Salomon]

Makes sense to me Bob.

I have checked GG placement on many cameras and holders.

Please consider revealing the Zero GG manufacturer, the resulting furor may be interesting.

Yet not the last word in ' best' or finest engineering as you imply from your Kodak Quick Load comments.

GG specs are in a range for very good reasons. Stack up differences are what matter.

A Japanese camera.

[Tin Can]

A Japanese camera.

That was my guess.

Thank you

[Drew Wiley]

Tim, I doubt you can do it by cutting away just one inner fin. The film has to be set straight down. A small amount of perimeter space between the adhesive strips and film edge is OK, like Sinar did it.

[Tim V]

Thanks, Drew.

[Pere Casals]

Well, given my own results from adhesive holders (both mine and Sinar's are simply modified Lisco holders with only about 2 mil of added adhesive thickness),
...
I would take a small fortune to get 3M to custom cut another batch of full-sized sheets of the correct Post-It adhesive

I managed to shot 9x12cm sheets in 4x5" holders by simply spraying 3M Re Mount glue in the septum, worked perfectly. I made a cardboard mask to not reaching the frame with the spray, that glue dose may be well used for a dozen of sheets, but before reloading it has to be checked. One can remove the glue with a solvent (that not damages the septum's paint).

After removing the exposed sheet I placed a dummy sheet in the sprayed area to protect the glue until the holder is reloaded.

The 4x5 holders have septum depth specified with a 7 mils tolerance, 2mils are not too much, but I'd say that spraying the glue on the septum adds a lower negligible thickness.

[MartinP]

I recall seeing a vacuum-based film-flattening 8x10" DDS which had the non-film side modified to look like funnel in the middle. One was meant to suck through a tube, via the funnel, through holes made in the septum, to get the film flat for the exposure. I assume it was homemade. At the time I didn't think to ask what the guy did for, say, a sixty-second exposure. Very possibly there was originally a small electric vacuum pump involved of course. Is this the sort of thing meant when posters have mentioned vacuum-holders earlier in this thread?

[ETA. The adhesive based idea seems much simpler and more practical.]

[Bob Salomon]

I recall seeing a vacuum-based film-flattening 8x10" DDS which had the non-film side modified to look like funnel in the middle. One was meant to suck through a tube, via the funnel, through holes made in the septum, to get the film flat for the exposure. I assume it was homemade. At the time I didn't think to ask what the guy did for, say, a sixty-second exposure. Very possibly there was originally a small electric vacuum pump involved of course. Is this the sort of thing meant when posters have mentioned vacuum-holders earlier in this thread?

[ETA. The adhesive based idea seems much simpler and more practical.]

Check the old Hoffman Vacumm Holders or the Linhof ones.