What is "lith" printing, anyway?

Discussion in 'Darkroom Developing and Printing' started by David Nebenzahl, Apr 1, 2004.

  1. After reading the recent thread on this subject here, I must confess I don't
    know what the hell "lith" means.

    I used to think it simply meant extremely high-contrast prints, or prints made
    from high-contrast negatives, since this is the type of processing used in
    photolithography (see below). But now I can honestly say I don't know what it
    mens.

    By the way, a word or three on the word "lith". Pardon me if this bores any of
    you, who already know all this stuff, to tears, but as a working
    "lithographer" I feel entitled to give this (ahem) lecture.

    By "lithographer", I mean I am an offset press operator. The fancy snob
    50-cent version of this term is "offset lithography". I'll explain the
    "offset" part in a moment, but "lithography" refers to the historical origins
    of this printing process.

    Lithography, which is still practiced by artists (not by commercial printers
    like myself), is literally "printing from a stone" (from the Greek "lithos",
    stone). In this process, a large rectangular stone is dressed flat and
    polished smooth. The artist draws on this polished surface with tools
    (pencils, crayons, etc.) which leave a greasy mark on the surface: these marks
    become the printed image. The process is based on the principle that oil and
    water don't mix. The image parts of the stone (the marks made by the artist)
    are receptive to the printing ink, which is oil-based, while the non-image
    parts are receptive to water, which repels the ink.

    To pull a print, the stone is first covered with a thin film of water. Then
    ink is spread over the stone using a brayer (roller). The ink only sticks to
    the image areas, while the water repels the ink everywhere else. After putting
    paper over the stone, the whole business is run through a press, making a
    print. (You can see the impression made in the paper by the stone in a
    lithographic print.)

    "Offset lithography" uses the exact same process, except that nowadays instead
    of stones, we use metal (or plastic) plates which are made photographically or
    by laser imagesetters. Like the stones, these plates are perfectly flat: the
    image area is not raised in relief, as it would be in letterpress printing (or
    sunk beneath the surface as it would in gravure printing). Like the stone, the
    non-image areas of the plate are hydrophilic/ink-repelling, while the image
    areas are hydrophobic/ink-receptive. The printing press has one set of rollers
    that apply water (actually a mixture of water and other stuff collectively
    referred to as "fountain solution") and another set of rollers (the "form
    rollers") that apply ink.

    Why "offset"? Unlike stone lithography, where the paper is pressed directly
    against the printing surface, an offset press first prints the image on an
    intermediate surface, a smooth rubber sheet known as a "blanket". The blanket
    then transfers the image to the paper. This is better than direct printing
    because it keeps a lot of the water from being transferred to the paper, which
    would make it quite soggy, and prevents paper dust and powder from grinding
    the image off of the plate. It also makes the printing plates "right-reading",
    rather than reversed as letterpress plates are.

    Just a few more notes, to bring this to some semblence of on-topicness. I said
    that the plates used in offset printing are made photographically. This is
    where "lith" film came in: the pre-press person first shot the camera-ready
    artwork in a large camera known as a "process camera", using lith film
    (Kodalith, for instance) to create an extremely high-contrast negative with
    only totally open areas corresponding to the black image, and totally black
    areas of background. After being "stripped" (cut and placed on a masking
    sheet) and "spotted" (where the inevitable dust spots were "opaqued out" by
    hand using red paint and a small brush), the stripped-up "flat" was placed
    against a photosensitized metal (aluminum) plate, "burned" in a plate burner
    using an electric arc lamp, then developed. Plate development could be done in
    ordinary room light (assuming you do it quickly) with a solution that removed
    the plate's coating from the non-image areas, leaving a colored (purplish or
    blue) image. Then the plate could be mounted on the press.

    All this is pretty much a thing of the past. Our shop doesn't even use metal
    plates anymore except for critical (like 4-color process) or long-run (>
    15,000 impressions) jobs. Like many printers nowadays, we have a direct
    digital platemaker (DPM) which is networked to our other computers. This
    machine uses lasers to image the plate material which is comes on a big roll
    and is imaged, developed, dried and cut to size by the platemaker. After
    making up the job using the design program of choice (Quark, Adobe
    Illustrator, InDesign, etc.), we "print" the document to our DPM, which spits
    out plates. These plates are polyester with a silver coating, black plates
    with a silvery image. We print from them, then toss them. Other digital
    imagesetters can make metal plates using a similar process.

    Other printers use imagesetters to make film, then burn metal plates from the
    film using traditional techniques. But the days of going through boxes of lith
    film are pretty much over, which explains why the stuff isn't available anymore.


    --
    .... but never have I encountered a guy who could not be bothered
    to make his own case on his own show.

    - Eric Alterman on his appearance on Dennis Miller's bomb of a show
    on CNBC (3/17/04)
     
    David Nebenzahl, Apr 1, 2004
    #1
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  2. lecture.

    Lots of snipping...

    Lith printing, as refered to here, is the development of
    conventional printing paper in diluted lithographic
    developer. The result is not extra high contrast but a
    curious effect of a very warm toned normal image overlayed
    by a high contrast image. The effects of infectious
    devlopment will also often produce speckles. Not all papers
    work well. There is a tremendous amount of stuff on the net
    on this process. The best book is one written by Dr. Tim
    Rudman, I think its title is "Lith Printing". An Amazon
    search for Tim Rudman as author will find it. He also hangs
    out on the Pure-Silver and Alternative Processes mailing
    lists and will answer questions.
    Say hello to the other chickens...
     
    Richard Knoppow, Apr 2, 2004
    #2
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  3. What David describes is true lith printing. A different kind of
    printing is also called "lith." Dr. Tim Rudman has the definitive book
    out about this. Basically, you overexpose a sheet of appropriate paper
    (sterling lith or some regular papers), and you develop by inspection in
    very dilute lith developer. You then snatch the print during
    infectious development occurs. Infectious development is approximately
    logarithmic in speed. It can go quite a while with nothing happening,
    and then bang! You'd better snatch the print at the right moment. You
    can get very interesting results with this process, including very high
    contrast, pixalated shadows, and wildly variable colors. Development
    time is often 5 to 10 minutes, and I've even had to go to 40 minutes to
    get what I wanted. You can see examples in a number of places,
    including Rudman's book, Eddie Ephraum's Creative Landscape Photography
    and elsewhere.

    -Peter De Smidt
     
    Peter De Smidt, Apr 2, 2004
    #3
  4. David Nebenzahl

    Tony Wingo Guest

    Tim Rudman has an introduction to Lith Printing at

    <http://unblinkingeye.com/Articles/Lith/lith.html>
     
    Tony Wingo, Apr 2, 2004
    #4
  5. Tobias Begalke, Apr 2, 2004
    #5
  6. Sorry, I don't read or speak German. Isn't that a little presumptuous of you?


    --
    .... but never have I encountered a guy who could not be bothered
    to make his own case on his own show.

    - Eric Alterman on his appearance on Dennis Miller's bomb of a show
    on CNBC (3/17/04)
     
    David Nebenzahl, Apr 2, 2004
    #6

  7. No, it's not, since the responder clearly was citing the site as
    providing examples of lith printing, which would be useful even if you
    don't speak German. If this is how you respond to people trying to be
    helpful, then people will stop being helpful.

    -Peter De Smidt
     
    Peter De Smidt, Apr 2, 2004
    #7
  8. David Nebenzahl

    Dan Quinn Guest

    I was one of those. My job ended with work at the press; Multilith
    IIRC.
    Prior to the press I took the pictures. The film and 4x5 print
    processing was farmed out. With prints delivered I was back at work
    making ready copy, tacking lith film to the stickyback, setting the
    screen, etc.
    Following that was the lith processing which included checks for
    correct dot formation. I did not burn the plates but did do the rest
    through a press run. Dan
     
    Dan Quinn, Apr 3, 2004
    #8
  9. David Nebenzahl

    jjs Guest

    Oh. How disappointing. I thought you did the old stone litho stuff. :)
     
    jjs, Apr 3, 2004
    #9
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