ANSI Film Holder Details

I know this has been asked before, but I couldn't find a suitable answer in the archives.

Where can I find the ANSI measurements (in millimetres, preferably)for a 5x4" fi lm holder ?

Also, what is the normal thickness of film (Kodak Tri-x)?

Finally, I stripped down a 5x4" film holder a few years ago, but can't remember how the light-trap was constructed. Is it brushes, rubber or felt, or something else.

I'm planning to make some film holders that use a plate instead of film.

Thanks in advance.

David Nash

If you know the ANSI specification (or document number), you can go to www.ansi.org and perform a search. You can search for other text, but you'll get narrowed results if you know the ANSI reference info.

You can also look up design information for particular manufacturers on the US Patent Office web site.

The URL for the US Patent Office is www.uspto.gov.

Sorry for three in a row. These are the correct links: www.ansi.org and www.uspto.gov.

The ANSI document # is Z38.1.51-1951 Inasmuch as this is an American standard, the measurements are in inches. There should be a European standard as well. If you need a specific dimension, let me know and I'll look it up. The light trap is typically a piece of spring metal, cut in such a way as to create "fingers" and covered in velvet. It just press fits in such a way that it straddles the septum. This is just one type. Over the years as the style and materials changed, I'm sure there have been other designs. Hope this helps.

Robert: Could not find the document you gave the number for in an ANSI search, however, I found the following in a search:

http://webstore.ansi.org/ansidocstore/product.asp?sku=ANSI%2FPIMA+IT3% 2E108%2D1998

There the following document is shown: Document Number: ANSI/PIMA IT3.108-1998 Photography (Accessories) - Double Film Holders of the Lock-Rib Type - Dimensions (revision and redesignation of ANSI PH3.108-1988)

That sounds like it. I've obviously got an old, old document. But then again, my film holders are old.

It looks like it’s not on the ANSI site anymore. I’ve uploded an updated version from a table by a guy named Hoover here.

This is the source I use to for the dimensions, to build my DIY holders, for dry plate in my case:

http://home.earthlink.net/~eahoo/page8/filmhold.html

Attachment 176913

pd: Like previous post

The other piece of the puzzle is nominal dimensions and tolerances for sheet film. That can be found in ISO 1012:1998. I’ve settled on ensuring my dry plate dimensions conform to that standard.

There is a corresponding standard for plates, but lists only a small selection of sizes that, with a few exceptions, do not cover general photographic plates - ISO 14548:1998. My guess is the plate sizes listed in 14548 are for holography, x-ray, and observatory astrophotography. I’ve sent an email in to ANSI requesting to expand the standard to be more useful to our type of plate photography.

Pere: Please do NOT rely on the link you cited in post 10. It contains misleading and erroneous information. Most important, the critical depth to film surface is actually the distance from the film holder to the septum. The distance to the emulsion can be as much as 0.012 inches or 0.3mm less. This error can cause a noticeable loss in sharpness when using fast lenses. The exposure height figures are obviously wrong. The figures do not include tolerances, which should be important to anyone relying on them to produce film holders.

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Originally Posted by Jim Jones

Pere: Please do NOT rely on the link you cited in post 10. It contains misleading and erroneous information. Most important, the critical depth to film surface is actually the distance from the film holder to the septum. The distance to the emulsion can be as much as 0.012 inches or 0.3mm less. This error can cause a noticeable loss in sharpness when using fast lenses. The exposure height figures are obviously wrong. The figures do not include tolerances, which should be important to anyone relying on them to produce film holders.

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Jim, I guess you are speaking about post 9.

both links have the same information:

http://home.earthlink.net/~eahoo/page8/filmhold.html

https://temp.animaux.de/filmholders.html

the depth to film surface is the dimension that has a tolerance: +/- 0.1778mm

So for 4x5 the "Depth to film surface" isn't 5.0038 +/- 0.1778mm ???

What's the right depth ???

This is the single dimension that I'm concerned !

I was planing to make a film to GG focus alignment test, but i'd like to know the right depth for 45, 810 and 1114


PD: Thanks Jim, I found it, here there is the information:

http://www.largeformatphotography.info/holders.html

Here it explais the septum vs film discrepance:

http://www.largeformatphotography.in...epth-ANSI-spec

The values for the T measurement shown in post 9 are correct

The label is wrong it should be "depth to septum" In the ANSI listing it is refereed to as the "T" measurement.

The ANSI/PIMA IT3.108-1998 I downloaded from ANSI years ago agrees with Richard Ritter and includes the metric T distance of 5 +/- 0.178 mm for holders 2x3 to 4x5. For 5x7 it is 5.79 +/- 0.254mm. For 8x10 it is 6.60 +/- 0.406 mm. For 11x14 it is 8.43 +/- 0.406 mm. For 14x17 it is 8.13 +/- 0.406 mm. Some sources give slightly different dimensions, apparently from converting between metric and inches. Someone could do this site a great service by verifying, consolidating, and publishing correct information on film holder dimensions in an appropriate place.

I’m happy to doublecheck all the values and update my table if you are OK to share the ANSI file.

I'd like a look at the ANSI standard as well. I went to ANSI's website to buy the damned thing and eliminate the confusion only to find they no longer have a listing for "ANSI/PIMA IT3.108-1998 American national standard for photography (cameras) : double film holders (lock-rib type)-- dimensions". The closest-sounding thing they have a listing for is "MIL-H-3526C NOT 1 Holder, Photographic Sheet Film, Double, Lock Rib". For $25, I'd like to know that's an equivalent document before I spend the money.

Found a breadcrumb. The standard we're looking for had a proposed status change to Withdrawn in January of 2003. This was under the care of something called the International Imaging Industry Association (I3A). The I3A was a merger of Photographic and Imaging Manufacturers Association (PIMA) and the Digital Imaging Group in 2001 but I3A was disbanded in 2013. So it looks like IT3.108-1998 isn't a standard ANSI provides (or even keeps track of) anymore and even the group responsible to killing it has died.

If anyone actually has a copy of IT3.108-1998, I'd very much appreciate being given a copy since it can no longer be obtained through ANSI.

Thanks for the insight!

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Originally Posted by williaty

If anyone actually has a copy of IT3.108-1998, I'd very much appreciate being given a copy since it can no longer be obtained through ANSI.

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Me too!

IMHO this post solves the thing: http://www.largeformatphotography.in...post164959IMHO.

As the "Depth to film surface" here http://home.earthlink.net/~eahoo/page8/filmhold.html

is in reality "the depth to the septum" then the manufacturing of the holder is well determined.


The distance from GG to the film surface is in fact a parameter of the camera back, not of the holder.

In fact the holder cannot have the "Depth to film surface" technically specified because it will vary depending on the thickness of the film we use !!!!

With glass plate holders this was not an issue, because a flange is ensuring the position of the emulsion surface.

In the case of film, the reference surface ensures the position on the back of the film, so the emulsion position has an slight variability depending on the film thickness, that I guess is of little relevance in practical conditions. But confusion comes from that...

(this is IMHO)

I’d think the variance in the thickness of the film should be well within the tolerances. I have no data though.

Still I’d love to see the original ANSI spec, especially to see if there are more details.

Quote:

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Originally Posted by animaux

I’d think the variance in the thickness of the film should be well within the tolerances. I have no data though.

Still I’d love to see the original ANSI spec, especially to see if there are more details.

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The tolerance is for the Septum position, not for the film position, the Septum can be at the limit of the tolerance because manufacturing variability, plating flatness, etc.

The actual tolerance we have for film surface position is on film DOF, considering our desired CoC, measured from the GG inner side.

Then we will not place exactly our film surface where the frosted GG surface was, because we have a variability from the holder (septum) tolerance added to the film thickness variable and flatness miss.

There is an specification missmatch between the GG position from the flange vs the "depth to the septum". This difference is just the "theoric" film thickness.

IMHO this is the source of all confusions, one value is for holder manufacturers and the other one is for camera manufacturers. The discrepance allows Kodak and Ilford to put the emulsion on a plastic base of a certain thickness.

Regarding that, perhaps the thick RX film may require a focuss correction, I don't know if RX shooters are aware of that...

I've used sheet film varying from .004 to .010 inches thick. This, in addition to the +/- 0.007 tolerance in the "T" dimension and the 0.012 width of the film slot, makes precise positioning of the film impossible. Some of the alternate methods of accurately positioning the film are mentioned here :https://www.photo.net/discuss/thread...holders.29599/. Another possibility would be a film holder with the film pressed from behind into close contact with a glass plate. The glass plate may need anti-newton ring surfacing on the rear and multi-coating on the front. What a pain to keep it clean! Perhaps some of the techniques needed to fabricate integrated circuit masks could be modified to be practical in sheet film holders, but that's beyond my experience.

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Originally Posted by Jim Jones

[... snip helpful information ...] Another possibility would be a film holder with the film pressed from behind into close contact with a glass plate.

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That's one method used for a 5" military aerial camera: the film is tightly pressed against a Réseau plate, exposed, the pressure plate is withdrawn, film advanced - repeat. I have such a plate and it is amazing. Unfortunately I can't remove the fiduciary markings. :)

Jim good analysis method but your conclusion about tolerances doesn’t jive with reality. If it was impossible to position film at the proper distance then we’d rarely see focused images at say (DoF calc) f/16 without Herculean efforts on the part of the photographer to select and trim/shim film holders and the specific sheets of film.

On the contrary, you can get well focused shots at f/5.6 for 4x5 as long as your ground glass is shimmed properly, with whatever holder you slap in there loaded with who knows what and over a wide range of temperatures (thermal expansion).

So what are the real tolerances stack-ups controlled to? They *must* be less than .005” or so if you start digging into the math.

Quote:

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Originally Posted by Jim Jones

I've used sheet film varying from .004 to .010 inches thick. This, in addition to the +/- 0.007 tolerance in the "T" dimension and the 0.012 width of the film slot, makes precise positioning of the film impossible.

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Anyway it's very difficult to adjust 0.2mm with the focusing adjustment, and if the subject has some depth then it's irrelevant... also for sure a regular view camera has more than a 0.2mm alignment mismatch from corner to corner.

I guess than regarding film flatness it is important to have it curled in a way that that sides are elevated compared with center, in that way it remains perfectly flat, in the same way that paper in easels.

Another way is spraying 3M Re Mount glue to emulate Sinar adhesive holders...

This thread also is reminding me that there's a good reason I find it a bit frustrating to shoot portraits with a 150mm f/2.8 on 4x5"!

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Originally Posted by williaty

This thread also is reminding me that there's a good reason I find it a bit frustrating to shoot portraits with a 150mm f/2.8 on 4x5"!

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If we listen to Pere, we all must give up and let Pere take all the pictures.

Sorry Pere, but the detail you extend is often overbearing.

Your posts make good reading yet are very difficult to conceive.

Don't stop! Just think. :)

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Originally Posted by Randy Moe

If we listen to Pere, we all must give up and let Pere take all the pictures.

Sorry Pere, but the detail you extend is often overbearing.

Your posts make good reading yet are very difficult to conceive.

Don't stop! Just think. :)

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Randy, it is not mandatory to read all what I post, that's optional :)

Anyway this has been an interesting thread, there is a discrepance in the GG to flange vs depth to Septum specification, what's me I finally learned why.

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Originally Posted by Pere Casals

Randy, it is not mandatory to read all what I post, that's optional :)

Anyway this has been an interesting thread, there is a discrepance in the GG to flange vs depth to Septum specification, what's me I finally learned why.

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I think the loss of ANSI continuity is a problem.

I collect film holders, or rather for a year I collected film and plate holders. Many variations. I have Hasselblad film holders, Hassy quality, spring backed plate septem 2.5 insq. Sharp negs. PITA

Horseman sold a camera that only can accept a wood holder, not a plastic one, missed it by that much...almost invisible with both in hand. PITA

And up to ULF. Big variations. PITA

I have measured many holders and cameras. I have a Deardorff S11 Factory 11X14 back that is 0.125" short, meaning too close to GG. I had a new one made. I could have shimmed. PITA

What we need is what we used to reverse engineer auto engine parts. I never used it, as it had a dedicated user in a clean room. But I would love to see what really is going on, on the septum surface. PITA

The company was USA based and owned, copycat was invented here. Stealing Engineers a favorite ruse. Counterspies. Spy vs Spy. PITA

After a while we just want a product, fix it next iteration. PITA

So it goes.

PITA = pain in the ass

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Originally Posted by Randy Moe

I think the loss of ANSI continuity is a problem.

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Aparently the ANSI-spec has been transfered to the PITA, with all its infamous consequences.

Unsatisfied with Edward A. Hoover’s extract of the specifications, I created a more complete table of the measurements with my own illustrations. It’s in original metric units though.

Now available at the same address here: https://temp.animaux.de/filmholders.html

May the tinkering begin!

Quote:

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Originally Posted by animaux

Unsatisfied with Edward A. Hoover’s extract of the specifications, I created a more complete table of the measurements with my own illustrations. It’s in original metric units though.

Now available at the same address here: https://temp.animaux.de/filmholders.html

May the tinkering begin!

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Where did you find the original document to develop yours from?

Well done!

As good as it gets. That's a compliment.

I find 'H' slightly tight. Many existing holders have greater 'H' as my Kodak sheets are loose. 0.007" film plus emulsion.

I realize it's a min value. I hope new 'makers' realize that.

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Originally Posted by williaty

Where did you find the original document to develop yours from?

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A friend had a copy.

Quote:

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Originally Posted by Randy Moe

Well done!

As good as it gets. That's a compliment.

I find 'H' slightly tight. Many existing holders have greater 'H' as my Kodak sheets are loose. 0.007" film plus emulsion.

I realize it's a min value. I hope new 'makers' realize that.

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Cheers! Hope it helps! My holders can all take print paper too. I wonder how thick that is.

The main a-ha from the original spec was that most values are min- or max-values.

That's the clearest example of film holder dimensions I've seen. Thanks!
The A min for 8x10 holders looks wrong, though.

Kumar

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Originally Posted by animaux

Cheers! Hope it helps! My holders can all take print paper too. I wonder how thick that is.

The main a-ha from the original spec was that most values are min- or max-values.

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Ya, I looked you up, you do a lot of paper negs.

I just miked processed MG RC at 0.010" I make you convert. All my tools are SAE.

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Originally Posted by B.S.Kumar

That's the clearest example of film holder dimensions I've seen. Thanks!
The A min for 8x10 holders looks wrong, though.

Kumar

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Compare Amin to Gmax on 5x7 doesn't make any sense either. The specs say that the overall length of the film holder has to be a minimum of 100mm-ish (4 inches) past the lock rib. I've never seen a 5x7 holder more than 50mm past the lock rib.

Amin for 11x14 and 14x17 can't be right either as that would make the length of the film holder smaller than the film in the holder!

This is a great service to the large format community. I could never have done as well. A more compact format may be more convenient to the user.

A min for 5x7 through 14x17 are transposed. A min for 5x7 should be 213.92: for 8x10, 295.28; for 11x14, 411.18: for 14x17, 496.90

G min for 8x10 should be 275.34. not 275.53

You have transcribed the T distance for 11x14 and 14x17 exactly as it is in ANSI/PIMA IT3.108-1998 including the inconsistency in the original.

Thanks for your input guys! Will look into it and try to correct the errors later on.

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Originally Posted by Randy Moe

Ya, I looked you up, you do a lot of paper negs.

I just miked processed MG RC at 0.010" I make you convert. All my tools are SAE.

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I did a few paper negatives, I wish I had the time to do a lot of them :·)

I just checked the thickness of Ilford MG IV paper. It’s 0.009" = 0,23mm

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Originally Posted by Jim Jones

This is a great service to the large format community. I could never have done as well. A more compact format may be more convenient to the user.

A min for 5x7 through 14x17 are transposed. A min for 5x7 should be 213.92: for 8x10, 295.28; for 11x14, 411.18: for 14x17, 496.90

G min for 8x10 should be 275.34. not 275.53

You have transcribed the T distance for 11x14 and 14x17 exactly as it is in ANSI/PIMA IT3.108-1998 including the inconsistency in the original.

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Thanks, I’m happy if this helps people building interesting things! It was fun to do this too.

Also, thanks for pointing out the errors. I think I fixed the translocated and incorrect values. Will do a doublecheck later on.

As for the T-inconsistencies for 11×14 and 14×17 — what should be the right values? In the ANSI there is also a table with imperial conversions. Those are identical.

There are some other areas that look suspicious. For example: Why are only negative tolerances allowed for some of the M1/2 values? Should M2 really be 1.57 on 4×5 holders?

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Originally Posted by animaux

Should M2 really be 1.57 on 4×5 holders?

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On my Fidelity and Lisco-Holders M2=1.57mm seems to be correct.

Quote:

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Originally Posted by B.S.Kumar

That's the clearest example of film holder dimensions I've seen. Thanks!

Kumar

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+1

Quote:

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Originally Posted by animaux

Thanks, I’m happy if this helps people building interesting things! It was fun to do this too.

Also, thanks for pointing out the errors. I think I fixed the translocated and incorrect values. Will do a doublecheck later on.

As for the T-inconsistencies for 11×14 and 14×17 — what should be the right values? In the ANSI there is also a table with imperial conversions. Those are identical.

There are some other areas that look suspicious. For example: Why are only negative tolerances allowed for some of the M1/2 values? Should M2 really be 1.57 on 4×5 holders?

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You need to look at current ULF film holder builders who may not be forthcoming.

Some sites have Data.

They can come forward or not.

After all, they are trying to run a business in a shrinking market.

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Originally Posted by Randy Moe

You need to look at current ULF film holder builders who may not be forthcoming.

Some sites have Data.

They can come forward or not.

After all, they are trying to run a business in a shrinking market.

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There is some discussion about 14×17 holders in this thread, with some actual holder builders taking part.

Considering the allowed tolerances for »T« with 14×17 holder add up to slightly more than 4/5ths of a mm, the values mentioned seem to be well within these.

Not sure about ULF, but with 8×10 holders Intrepid is not able to keep up with the demand. I’ve ordered one about 4 months ago, still waiting for it. I think most people who try to build their own holders are mostly not the same ones buying professional holders.