Re: Ilford EXPRESS paper
<jjs> wrote in message
news:13olf6vie0vhicb@news.supernews,com ...
>
> "Richard Knoppow" <dickburk@ix,net com,com > wrote in
> message news:13ol5oua49m6ue3@corp.supernews,com ...
>>
>> <jjs> wrote in message
>> news:13oiskeojnvdm1c@news.supernews,com ...
>>>
>>> "Richard Knoppow" <dickburk@ix,net com,com > wrote in
>>> message news:13oiq2hgu33rj54@corp.supernews,com ...
>>>
>>>> The ISO speed as given in the data sheet is no
>>>> faster than that for most variable contrast enlarging
>>>> paper. However, the paper is intended for use in
>>>> automatic printing machines where the exposure is to
>>>> relatively intense light for very short times, probably
>>>> less than a second. Most enlarging paper is intended
>>>> for exposures of from about 10 or 15 seconds to a
>>>> couple of minutes, typical exposures being around 15 to
>>>> 45 seconds. This paper is probaby adjusted so that
>>>> reciprocity effects, etc, are optimized for the short
>>>> exposure. This may mean a shift in overall contrast or
>>>> in the spacing of contrast with various filters or
>>>> other differences. I am sure the paper is quite usable
>>>> for normal printing but it may not behave in exactly
>>>> the way the contrast specs would have you expect. Since
>>>> your application is for hand processing I doubt if this
>>>> will cause any significant problems.
>>>
>>> Thank you again, Richard. I have just installed an
>>> Ilford VC head for 4x5 work and will try that paper at
>>> near 1:1 enlargement late next week. I wonder if this
>>> paper has a particularly energetic developer in the
>>> emulsion. I recall one time you posted how one could
>>> tell by having a developer of a simple solution. I would
>>> be most grateful if you could tell us again about that.
>>>
>>> Very Best,
>>>
>>> JJS
>>>
>> Ilford does not indicate if the paper has included
>> developer or not but I suspect it does not. One way to
>> tell is to "develop" a scrap of the paper in a strongly
>> alkaline solution. If there is incorporated developer it
>> will turn black. If not it won't. For the most part the
>> effect of incorporated developer when a normal developer
>> is used instead of an activator is to increase the speed
>> of development somewhat. That is the image will come up a
>> bit faster. It may also extend the capacity of the
>> developer somewhat. Activation results are never quite as
>> good as normal development.
>> From what I can learn from the Ilford material the
>> main and maybe only difference between this stuff an
>> normal VC paper is the optimization for very short
>> exposures. This may not have much effect on longer
>> exposures but you will have to experiment to find out.
>> Also, I expect an e-mail or phone call to Ilford would
>> elicit more information.
>>
>>
>> --
>> ---
>> Richard Knoppow
>> Los Angeles, CA, USA
>> dickburk@ix,net com,com
>
> The whole post is included because it is very important.
>
> One more thing, Richard. Ilford makes an RC paper
> developing machine that takes a print into developer,
> stop, fix and (it appears - no wash!) to a dry print in
> something around a minute to eighty-seconds. I wonder if
> the Express paper isn't intended just for such setups.
>
> Thank you once again for your help, Richard. I believe
> there is a book to be made of your contributions.
>
> Very Best,
> jjs
>
Thanks for the compliment:-)
Do you have a link to the Ilford machine? I am curious
about it. In the past a system called stabilization
processing was used for rapid access prints. This used a
bath in a stabilizer to eliminate the need for fixing and
washing but such prints are not stable for long periods.
While they won't turn black in the light as would be normal
for an unfixed print they will begin to degrade in weeks or
months unless subsequently fixed and washed. I don't think
this process was ever used for RC prints so I am curious
about what the Ilford machine does.
RC can be processed pretty quickly. Say 45 seconds
development, less than a minute for fixing (strong rapid
fixer) and perhaps a 1 minute wash. This is still longer
than the machine but pretty short.
Ilford does not appear to use incorporated developer in
its other RC papers but this may be an exception. There is
some image quality loss when an activation system is used
compared to normal development so I am skeptical it would be
used for photo-finishing.
A call or e-mail to Ilford should settle this.
--
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@ix,net com,com