ilfolith IH4 film useage?

[Discoman]

I have a box of ilfolith IH4 film that I intended to start working my way through to try it out and get some cheap photos $2 for the unopened box!)
I tried at photo.net to find any sort of help so I could properly expose it in camera, only to be told it doesn't have any sort of rating.
The rest of the replies were even less helpful than that, mainly to the tune of "buy some real film."

What would be a base exposure rating? Is a lith developer necessary, or can I just use the standard D76? I've processed color film in it by using full-strength developer.
I wanted to load up a film holder or two and just go grab a couple pictures from a local state park. About what ISO should I use for the film for estimating sunny 16?
Thanks in advance.

[JoJo]

Even when I did not find any technical specs, this might be an orthochromatic film for graphics art.
The film is ultra-hard in contrast comparable to grade 5 or 6. You will not see much grayscale in the resulting picures.
Normally, such film sensitivity is similar to paper. maybe 3-6 ISO.
If your camera or light meter allows 12 or 15 ISO, additional open the aperture 1 stop or double exposure time.
You can process this kind of film under red light and use standard paper developer. But developing times may vary from 1 minute to 4 minutes, depending on the developer. Best will be to develop the film under visual control and red light.
This film seems to be very very old. It is possible that you get strong fog using standard developer.
Very intense agitation during developing is necessary.

Normally, sheet film for graphics does not have marks at the edge. Under red light, the more bright side is the emulsion side.

Joachim

[Ian Grant]

Thats old film, Ilford sold their Graphic Arts and Medical side to Agfa many years ago.

It's a Lith film so of extremely high contrast even more so than the line films which can sometimes be used to make continuois tone negative. It is orthochromatic.

You'll need to use a very dilute developer to help tame the contrast Maybe D76 at 1+9 would be a good starting point for 3 mins.

Ian

[Simon R Galley]

Dear Discoman,

Ian is spot on, this film is decades old....so 90% sure will be useless, do a test exposure in you garden rate it at 15iso then process in any dilute paper dev. If its not fogged it will be black and white ( lith was for basically photographing text items for print ).

Simon ILFORD Photo / HARMAN technology Limited

[Discoman]

Okay, high agitation and paper developer. I can work on taming contrast if I dislike the effect, assuming it works.
That is for the help.