Half tone screens and half tone negative reproduction

[Struan Gray]

Bob. You sound as if you want to add gravure-style stippling to gum or carbon prints. If you are lucky enough to have some colour gravure workers whose prints you can look at, they will give you an idea of the graphical potential.

With stippled/halftoned techniques it is easy to get posterisation in the transitions to the brightest highlights and/or deepest shadows - you have to control whether and how the plate transitions to no dots or all dot. Traditional gravure has the advantage over most other dot-based processes that the holes (dots) holding the ink can be made to vary in depth as well as density. All the same, most modern gravures I have seen are more 'graphic' in their treatment of tones than a carbon print. Classic gravure for book production and the like used mask-making and/or retouching to avoid this look. High quality CYMK halftone printing also used masks for highlight and shadow protection, and general contrast control. With a digital step, all of this can be combined in one output film for each colour, but without it, things get complex fast, requiring craftsmanship and artistry, and a knowledge of your particular press, inks, and paper for best results.

The Getty Atlas of Photographic Processes has a section on halftone, which gives a good introduction to the possibilities:

http://www.getty.edu/conservation/pu...ons/atlas.html

Otherwise, the best, most detailed information on halftoning I have found has come from books and research papers published in the 50s and 60s. Best of all was John A. C. Yule's 'Principles of Colour Reproduction':

https://books.google.co.uk/books?id=U_QeAQAAIAAJ

[Struan Gray]

PS: I have a set of Polaroid screens. They have metal 'wings' along the side that were meant to be inserted into slots in a special holder, which also had a slot for a Polaroid sheet film holder like the older 500 series models. I found I could just place the screen (carefully) in the opening of an international back, holding it in place with a film holder and the spring pressure from the gg.

The coarsest screen was 65 lpi, which may be a bit fine for t-shirt work.

Note that these are ruled-line screens, which need to be held at some separation from the film to work properly. Modern screens are more often contact screens, which are easier to use, but less flexible (with a ruled-line screen you can adjust contrast by varying the height of the screen).

The screens work, but limit you to 4x5, which is a tad small for a shirt print.

[senderoaburrido]

The coarsest screen was 65 lpi, which may be a bit fine for t-shirt work.

The screens work, but limit you to 4x5, which is a tad small for a shirt print.

My thinking was that I could make an 8x10 litho or heavily overexposed xray enlargement of the halftoned product. From there I could do the t-shirt prints.
The alternative I envisioned was to enlarge the original halftoned product of 4x5 litho film onto a screen. I'm not sure whether that would work, as I'm completely unfamiliar with this process.

[Struan Gray]

If you have space, and if you really want to do this the analogue way, vertical graphics arts cameras like the Agfa Repromaster series usually go for free or peanuts if you can pick up. Find one with lens and halftone screens included and away you go.

I can't help feeling that you're making life unnecessarily hard for yourself though. If your goal was fine-art four colour gravure I could understand, but the very best T-shirt is not going to be able to justify the effort you put in. I personally would concentrate on getting the photograph right, and use a digital step to get it on the shirt.

[senderoaburrido]

I live in Montreal. I know this place used to be a big textile center. Maybe there is a graphic arts camera lying in a back room somewhere. I'll investigate that, thanks.

I know it seems unnecessarily difficult, and unreasonable of me. I just have an interest in doing it how it used to be done as an adventure of sorts. To learn how prints would have been made 30 years ago while simultaneously training myself in what will soon be lost skills. Who knows? Maybe vogue-obsessed youths of the 2030's will even pay me to do it "the old fashioned way".

I run a farm project in the summer to grow crops for myself for no other reason than to farm for fun. I have a habit of taking on activities just for the hell of it.

[Struan Gray]

Excellent attitude!

Have fun.

[barnacle]

I have a habit of taking on activities just for the hell of it.

I suspect that's why many of us are here. Certainly me - what else would account for the LF photography? (Not to mention sidelines like building the camera, rebuilding old cars, paragliding, etc, etc...)

Neil

[senderoaburrido]

I've got a question for those of you who have done this before: Do you know of any books or resources to look at for instruction on this process? I know there must be plenty of manuals out there. If I have a specific title, I can look that up in the library.

[andrewch59]

Hi Senderoaburrido, I have a old process camera in my shed which is 18 x 18 inch square, I am just coming to terms with half tone printing myself. I have a bigger Hunter Penrose camera that I a picking up in December that is also a process camera. It seems the LPI (Lines Per Inch) of the screen is of importance dependant on what kind of material you are going to print on. For me the old comic book dots would be pretty awesome to try. I already dabble in xray film photography so it would seem natural that if I could get a screen made with the lines etched on them I could just expose onto xray film and then make a carbon print which could be used as a printing plate???
Fortunately I have a friend who wants to revive his printing press, so it may be an amicable process for both of us. I think like you it is a way of staying traditional.