"Jean-David Beyer" <jdbeyer@[EMAIL PROTECTED]
> wrote in
message news:slrnfhnkan.2sa.jdbeyer@[EMAIL PROTECTED]
> On 2007-10-21, Richard Knoppow <dickburk@[EMAIL PROTECTED]
>
> wrote:
>>
>> "piterengel" <pslaviero@[EMAIL PROTECTED]
> wrote in message
>> news:1192991717.030130.83460@[EMAIL PROTECTED]
>>> Hi, becaise it no more possible to find lith film I need
>>> to try with a
>>> qute common film to obtain very high contrasted
>>> pictures.
>>> I have Efke
>>> KB 25 and Rollei PAN 25 at home. Can anybody suggest a
>>> developer to
>>> have extremely contrasted subjects?
>>> Thanks all
>>> P.
>>
>>
>> The highest contrast is gotten using a lithographic
>> developer like Kodak D-85 which produces "infective"
>> development. However, D-85, and similar developers, use
>> Formaldehyde, which is nasty stuff.
>
> I use Kodak litho film (not much) and one of their litho
> developers.
> It does not contain liquid formaldehyde, but
> paraformaldehyte that
> is a related compound. J.T.Baker have this to say about
> it:
>
> http://www.jtbaker.com/msds/englishhtml/p0154.htm
>
> As far as I can tell, I have never had any trouble with
> the mixed
> working strength developer.
>
>> There are somewhat lower
>> contrast developers, like Kodak D-8, using Hydroxide,
>> which
>> produce very high contrast but not quite what a true
>> lithographic developer gives. I don't think a lith
>> developer
>> is needed unless you are doing true line work.
>> Lith film is still made but I don't know where to get
>> it
>> outside of the US.
>> For pictorial purposes a print developer like Dektol
>> will give you quite a bit higher contrast on film than
>> the
>> usual film developers but at the cost of being quite
>> grainy.
>> Since print developers are cheap and easy to obtain I
>> would
>> try one first to see if the contrast is high enough.
>>
>>
>
>
> --
> .~. Jean-David Beyer Registered Linux User
> 85642.
> /V\ PGP-Key: 9A2FC99A Registered Machine
> 241939.
> /( )\ Shrewsbury, New Jersey http://counter.li.org
> ^^-^^ 18:20:01 up 15 days, 1:56, 1 user, load average:
> 5.22, 5.55, 5.14
Actually, D-85 uses paraformaldehyde, which is a
crystaline form and becomes formaldehyde in solution. It is
a two solution developer, the two parts being mixed just
before use. I don't know if there is a more environmentally
friendly substance that can be used in stead of the
paraformaldehyde. Its function in the developer is not as a
hardener but specifically to promote infectious developemt.
This causes dense areas to develop much more rapidly than
lower densities resulting in exagerated contrast. For the
most part lithographic developers were used for line work
where the negative needed to be either very high density or
clear. Lith developers are also currently used for lith
printing. This is a sort of special effect which has become
popular in the last decade or so. A Google search for lith
printing will give you lots of hits.
For just higher than normal contrast on pictorial film I
think less extreme developers will work fine. One can use
something like Kodak D-8 or D-11 but, as I mentioned before,
probably any print developer will be enough.
--
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@[EMAIL PROTECTED]
|
