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  1. #231
    kb3lms's Avatar
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    For backing paper, try Pacon 57305 Fadeless Art Paper, 48" x 50' roll, Black. You can get it from Amazon or any number of other places fairly cheap. A roll should last a long time.

    It is an opaque 20lb paper, like stadard white office paper, black on one side and white on the other. One layer will pass some light but two will not. You cut strips to the same shape and size as a manufactured backing paper and put the black side towards the film and the white side out. You can write frame numbers and whatever else you like on the white side. Put a layer of scotch tape around the ends where they fasten to the spools as the paper is not as strong as regular backing paper and will tear if you don't give some reinforcement but that was the only strength problem I have had.

    I have changed homemade several 620 size rolls in room light with no problem. (The emulsion used was a batch of TLF#2 @ ISO ~20.) I had no issues with the red frame number window on the camera but the emulsion was not spectrally sensitized, either. There were no problems with edge fog.

    -- Jason
    All this has happened before, and all this will happen again.

  2. #232
    kb3lms's Avatar
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    Grain

    IDK about being able to produce acceptable grain for smaller sizes. As I have mentioned elsewhere, I take scraps from my 120 size coatings and cut them up as sigle size 35mm frames. The grain is certainly noticeable, but not that bad. "Front Flower Bed" is my favorite 35mm example:

    https://www.dropbox.com/s/jmljo9oh57...tFlowerBed.jpg

    This was scanned on my Nikon LS-40 through Vuescan. It's been printed as an 8x10 and the grain is OK. Being non-modern film it is a little hard to print, though, and I don't feel that I've gotten a really good print but that's OT.

    It seems logical to me that as we all gain more experience the emulsions will get better. What is important is for all of us trying these things to keep posting / sharing what we learn.

    -- Jason
    Attached Thumbnails Attached Thumbnails FrontFlowerBed.jpg  
    Last edited by kb3lms; 11-07-2012 at 02:47 PM. Click to view previous post history.
    All this has happened before, and all this will happen again.

  3. #233
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    Yesterday at GEH I actually got to lay eyes on an old Kodak perforater ...... in the labs down here I've come across these two little film splitters with stickers that say RIT on them. They are for splitting 4" film down to 35mm, and the other is for splitting 35mm down to 16mm....
    Hey Chris,

    Could you snap some pictures of these gadgets? It would be great to see what they look like.


    Now, as far as punching is concerned, making a small punching block may be harder than you think. One of my projects that has held up my emulsion work was trying to punch 35mm because that is what I ultimately want, too. I was trying to punch acetate with 6 pairs of holes spaced for 35mm. Have not yet tried PET but I would expect it to be harder to do. Issues I came across:

    1) Quite a bit of pressure is required to punch more than about 6 holes so you need a fixture with some leverage. I would expect PET would need more pressure.

    2) Hanging chads are a real problem and they are hard to avoid without having to cut them off manually. Chads may be less of a problem with PET.

    3) Round holes did not work reliably in any (Pentax SLR) camera I tried. Lot's of problems with jamming. You need a rectangular hole but I don't think it needs to exactly match the ANSI spec. There is some tolerance.

    I had no real machining tools to do this and was just working with a dremel tool, nails (with the point cut off and then modified with a v-notch in the face) for the pins and aluminum for the die. So, I am not saying it cannot be done, these were just some issues that I found.

    -- Jason
    All this has happened before, and all this will happen again.

  4. #234
    Photo Engineer's Avatar
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    Jason, that photo is quite good, but I can see the grain. Did you notice that there was quite a bit of flare as well? This would need a good AH dye or absorber dye. And, unfortunately would cost you up to 1 stop in speed. This increases the speed / grain ratio even more than I mentioned in my previous post.

    Just FYI, the attached item shows how we make emulsions, coat film, and do the final operations of slitting, chopping, perfing and spooling. My thanks to the unknown artist who did this.

    PE
    Attached Thumbnails Attached Thumbnails Film Making.jpg  

  5. #235

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    Originally Posted by Steve Smith

    The rotating dies method is the way to go if you are doing a lot of film and want to run fast. The flat die method would be easier for a hand operated, low quantity production run.
    Quote Originally Posted by AgX View Post
    The funny thing is that it is just the other way round the industry does it...

    Actually it would be even harder to achieve high precision with rotating tools.
    AgX, the system I saw used rotary dies - they were trying to get out of the "flat die" method, which nevertheless was also used for automatic high production use. It's just that the advantages of the rotary system made it worthwhile; there is no risk of rubbing against machinery - with a rotary system, the moving film web can just "kiss" against the punch/die set which is moving at the same speed. Note that this was some years ago, when professional film production was probably at a peak.

  6. #236
    kb3lms's Avatar
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    Hi PE, that frame was scanned at 2900 dpi or whatever the Nikon does so you get the warts and all. Optically printed at 8x10, it looks about like Tri-X. I consider this to be a starting point. At least this batch did not go through the spoiling dept like the last one.

    The flare is what makes it different! Seriously, I have some thoughts on AH, but as you say they all would cost speed.
    All this has happened before, and all this will happen again.

  7. #237
    Brian C. Miller's Avatar
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    Quote Originally Posted by Photo Engineer View Post
    Just FYI, the attached item shows how we make emulsions, coat film, and do the final operations of slitting, chopping, perfing and spooling. My thanks to the unknown artist who did this.
    The art style looks like it was done by one of the "usual gang of idiots" at Mad Magazine. The one I'm thinking about did the last page in the magazine, before the "fold-up" page.

    (Memorable: man walking down the street past various shops and signs: "Phonebone's Glasses" with a huge pair of glasses, "Phonebone's Umbrellas" with a huge umbrella, "Phonebone's Wigs" with a huge wig, "Phonebone's Bandanas" with a huge bandana, "Phonebone's Shoes" with a huge pair of shoes. Then the fellow rounds the corner and there's a giant standing there wearing the glasses, holding the umbrella, wearing the wig and shoes, and the bandana is wrapped around his waist. Another sign reads, "Phonebone.")

  8. #238

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    Quote Originally Posted by kb3lms View Post
    Now, as far as punching is concerned, making a small punching block may be harder than you think. ... Issues I came across:
    ...
    2) Hanging chads are a real problem and they are hard to avoid without having to cut them off manually. Chads may be less of a problem with PET.
    ...
    3) Round holes did not work reliably in any (Pentax SLR) camera I tried. Lot's of problems with jamming. You need a rectangular hole but I don't think it needs to exactly match the ANSI spec. There is some tolerance.

    I had no real machining tools to do this and was just working with a dremel tool, nails (with the point cut off and then modified with a v-notch in the face) for the pins and aluminum for the die. So, I am not saying it cannot be done, these were just some issues that I found.
    Jason, thanks for the reality check. These are some of the issues I would expect. I think the solution to "hanging chads" is in extraordinary precision in the centering and clearance between punch and die. I'd guess that the speed of the punch is also a factor, as might be use of a high vacuum below the die set.

    Re: round holes: I don't think these are at all desirable for film transport (in cameras, etc). But "round" makes it simpler for a home machine shop to make punch and die sets, and to have these precision-aligned (within reason). It wouldn't be necessary to have the rotational alignment near perfect, as it would be with rectangular punches.

    I'm sure it can be done, I'm just saying the reality is a lot more difficult than it appears.

  9. #239
    Steve Smith's Avatar
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    Something we are about to experiment with at work for cutting 0.125mm polyester is a chemical etched tool. This might be suitable for small scale perforation punching and would be cheaper than a traditional male and female die set and probably cheaper than a steel rule die.

    Everything you ever wanted to know about cutting tools but weren't interested enough to ask: http://www.dieco.com/index.php/ddin-...-in-diecutting


    Steve.

  10. #240
    Photo Engineer's Avatar
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    AFAIK, Kodak made or had made for them, custom perfing and slitting and chopping equipment. The dies were replaced on a regular basis. The ones I saw were rotary.

    The cartoon style is Don Martin.

    And Jason, yes, we lose speed and that is why I said that this puts us in a worse position for speed/grain. We would probably turn an ISO 100 material with TriX grain into an ISO 25 - 50 material with TriX grain. Then the question is, is this suitable for 35mm. Probably not. For 120, probably but maybe marginal. For 4x5? Probably just right. But, IDK until I do the experiments. I have the AH dye here. It is an Oxonol dye that dissolves in developer.

    PE



 

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