What are Ortho Litho films used for (currently)?

[dcy]

I have three closely related questions:

1) What are Ortho Litho films used for?

I don't mean historically. I know that in the past they were used for copying, like in newspapers, or to copy documents. I wonder what market exists today. I use them to make large negatives for cyanotype, but I don't imagine that's a large enough market to merit the product's existence.

2) Why are they called "litho"?

I am familiar with lithography for the manufacture of semiconductors. I am vaguely aware of the lithographic technique for making stone lithographs. I am also vaguely aware of a darkroom technique called lithographic printing. None of these seem to involve film.

3) Is Inkpress Media Regent Royal Hard Dot an ortho litho film? (link, link)

It has broadly the same properties (orthochromatic, low ISO, very high contrast). The words "ortho litho" do not appear in the description, but it talks about pre-press applications which sounds to me like one of the traditional uses of ortho litho films. The description also mentions ACD chemistry, which also appears in the technical datasheet of Arista Ortho Litho.

Thanks for the help.

 

[MattKing]

2) Why are they called "litho"?

I am familiar with lithography for the manufacture of semiconductors. I am vaguely aware of the lithographic technique for making stone lithographs. I am also vaguely aware of a darkroom technique called lithographic printing. None of these seem to involve film.

Lithography was an integral part of the printing industry - newspapers, books, magazines, posters, banners et al.

That was the material that lithographers used to make the high contrast negatives necessary for "burning" the plates used to print on offset presses - the presses that were used to print much of the printed material seen by the world for a very long time.

They were also used to create the half-tone dot negatives that made photos possible in the newspapers printed with the older, lead type systems.

Lith (darkroom) printing only has its name because the high contrast developers used by lithographers happen to have another, not designed for use - when highly diluted, and with some papers, and when combined with unusual levels of exposure and extremely extended development times, you sometimes achieve really interesting results. As far as I'm aware, those effects were only stumbled upon after the printing industry mostly stopped using the old processes.

I actually have a small amount of direct experience with lithographic materials: using big horizontal cameras to make the half-tone negatives and the page size negatives of composed text and image windows, putting them together, burning the composite onto UV sensitive plates, "developing" the plates with intriguing smelling colourful goop, installing the plates on to offset presses and running lots of paper through those presses.
I actually have on my shelf a book that I did all of that for, including the binding.

 

[Paul Howell]

In the past films and plates were ortho, that's why when you look at landscapes taken in the 1800 and early 1900 the sky is blank, red sensitive, blue blocked like using a dark blue filter on pan films. Orth film rendered foliage well, as well along with pale skin tones, there was an othro Trix for black and white portraits. Orth film is very fine gain so for those who are looking to make large prints it can be useful. Others want to use for very high contrast prints. I'm not sure about Inkpress, I just ordered film which included a roll of Foma Ortho 400 for an experiment. Here in the low desert many clear days, want to experiemnt with landscapes. If orth film is as fine gain as is reported with 1/2 frame maybe possible up to 11X14.

 

[revdoc]

The Inkpress film is a lith film, as is the Arista film. In addition to the printing industry, they were also used in darkrooms to make masks for special printing techniques, such as inserting part of one image into another.

These films vary quite a bit. They can have different speed, different contrast and different Dmax, or respond to different developers. In the print industry they were often used with lith developers that promoted infectious development, producing two tones: dead black and clear film. They're designed for rapid processing (e.g., 30 seconds development time with developer at 30C), and have a very thin base that lets you contact print with either side up. You can often also expose it through the back.

I don't know why other people use it, but it can be used in camera as a very cheap large format option, in which context it might the the only affordable option for ULF It can be used to enlarge smaller format negatives for contact printing. I've done both with the Arista film, and it worked well in both cases. One other nice thing is that it will show some sky detail in landscapes.