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  1. #11
    Photo Engineer's Avatar
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    Quote Originally Posted by sanking View Post
    135mm Tmax-100 has a thicker base than 120 Tmax-100. That is true of most films. This adds more B+F density but does not change the characteristics of the film.

    I only mentioned thate I like T-MAX 100 in 120 size because I don't use it in either 35mm or LF, becaue 1) I don't use 35mm format at all, and 2) the film has a UV blocking base that makes it unsuitable for printing alternative processes.

    Sandy
    Sandy;

    Last I coated, all 35mm films and 120 films were on a 5 mil support, and 4x5 were on 7 mil support. The 5 mil is used to facilitate turning the sharp turns in the cameras, and allowing longer lengths to be spooled onto a roll. The 4x5 is designed to prevent buckling in the holder as are all ULF sizes.

    The use of UV or no UV may cause a change of a few microns, but this is peanuts beside 5 mil or 7 mil.

    PE

  2. #12
    David A. Goldfarb's Avatar
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    Even if the emulsions are the same, you might find you like a certain emulsion at a certain enlargement factor, but not at another. For instance, you might like the tonality of Tri-X in medium or large format, where the grain isn't as much of an issue.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
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  3. #13

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    Quote Originally Posted by Photo Engineer View Post
    Sandy;

    Last I coated, all 35mm films and 120 films were on a 5 mil support, and 4x5 were on 7 mil support. The 5 mil is used to facilitate turning the sharp turns in the cameras, and allowing longer lengths to be spooled onto a roll. The 4x5 is designed to prevent buckling in the holder as are all ULF sizes.

    The use of UV or no UV may cause a change of a few microns, but this is peanuts beside 5 mil or 7 mil.

    PE
    Ron,

    This surprises me. I thought it was you who told me that Kodak put their 35mm films on a thicker base than 120. Guess I got it mixed up.

    Sandy

  4. #14
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    Well, enlarged to the same proportion and viewed at an equivalent (for image size) viewing distance, the grain and sharpness from the 35mm should differ from the MF image. You see the grain stays constant in size, but is made larger when you print 35mm. OTOH, the micro contrast of a 35mm image is higher giving the image more apparent sharpness.

    I have posted data on this from the article by Kriss in another thread.

    PE

  5. #15
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    Quote Originally Posted by sanking View Post
    Ron,

    This surprises me. I thought it was you who told me that Kodak put their 35mm films on a thicker base than 120. Guess I got it mixed up.

    Sandy

    Sandy, you reminded me of this. I'm going to the lab and measure it. I'll post the figures in a bit.

    PE

  6. #16
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    Ok, I measured color and B&W 35mm and they are 5 mil + a hair. A fine hair for B&W and a thick hair for color. The 120 film was the same as the 35mm, or 5 mil + a hair. The sheet film was 7 mil + a hair. Same as for 35mm, the 'hair' varied for color and B&W. I have a roll of uncoated support and it is virtually 7 mil on the dot. That is the stuff from the formulary that I coat my 4x5 sheet film on.

    I have been using a 35mm strip to calibrate my coating blades to 5 mil. They are quick and easy to use and 0.1 mil or thereabouts is not much of an error. I use sheet film to calibrate to 7 mil undercut. So, I thought I remembered right and if I said otherwise, sorry.

    I would like to add that SO films are often coated on 2 mil support in order to load more film into cameras used for space missions and etc.

    PE

  7. #17

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    If both size negs were properly focused in camera and we can eliminate that as a cause of lack of sharpness in the print then it's puzzling. I have focused 120 and 35 negs with a grain focuser and while the grain in 120 isn't quite as easy to focus as in a 35mm neg it isn't that hard either. There are a number of things to try/questions to ask yourself:
    1. Is the grain focuser correctly focused? The Paterson for instance has a focusing line across the eye piece. You move the upper part of the focuser like a telescope until the line is sharp and tighten the body at that point. Even if you wear glasses normally you can dispense with these for focusing as long as the line is sharp without glasses.
    2. Focus at max aperture
    3. If there is/are letters/figures on the neg such as notices, car number plates etc, use these or alternatively use lines in the neg such as fence posts, windows etc especially where a light area meets a dark area.
    4. Turn off the safelight to avoid diffusing the enlarger light.
    5. When the grain begins to come into focus, continue to alter the enlarger bellows until it gets to the point where the grain becomes slightly fuzzy again and then re-adjust to the sharpest point again. That way you know you have go to the sharpest point.

    Best of luck

    pentaxuser

  8. #18
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    Just thinking out loud here....

    MF lenses may have different contrast and resolution than the lenses for 35mm equipment, so a film may be better suited to your needs in one of the formats.

    The other factor that might require consideration is that the geometry of the film may affect development somewhat.

    In particular, your method of agitation may interact slightly differently with the larger surfaces presented by 120.

    There may also be slight differences resulting from the fact that 35mm has sprocket holes, and that each "layer" of the 35mm film on the reel may be closer to the next one due to the longer length of a 36 exposure roll.

    I would think that each of these development effects would be small, but may be apparent.

    Any thoughts about this?

    Matt

  9. #19

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    Quote Originally Posted by sanking View Post
    Ron,

    This surprises me. I thought it was you who told me that Kodak put their 35mm films on a thicker base than 120. Guess I got it mixed up.

    Sandy
    Over the years I've always "known" that roll film is thinner than 35mm. From the recent pdf of Neopan400, the only 120 size film I use, the thickness of 35mm is 0.122mm and the 120 is 0.104mm.

    From the latest pdf for Ilford Delta400, the 35mm is 0.125mm and the 120 is 0.110mm.

    From the Kodak pdf dated September 2001 the thickness of 35mm Tri-X is 5-mil and the 120 film is 3.6 mil.

    So it seems that things are now different, at least for the new Kodak films (or perhaps just some of them).

  10. #20

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    First, when it comes to negative quality, there is really no substitute for square inches. Bigger negatives generally give better pictures.

    There have been some differences between 35 mm and 120 films in the past. That seems to be disappearing. The reason for the differences, when they occur, is the structure of the film. 120 film have a dead black paper backing. The back of the film is protected from the pressure plate, and the black backing helps prevent reflections. (This is not the case for 220, which is more like 35 mm.) 35mm films needed protection from the mechanical parts of the camera that touched the film back and the often rougher handling the film got from the 35 mm transport mechanisms. They also needed a more aggressive antihalation system (usually a soluble gray color on a back coating, and sometimes a gray colored film base). Most of the differences had to do with the antihalation coating and overcoatings. But even when the emulsions were the same, the differences in these other things made for a somewhat different look and sometimes different processing. To compensate, sometimes the emulsion was changed a bit. The more modern films are tougher, and antihalation techniques have improved, so the films can now be more the same.

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