Re: reciprocity failure and development times

Gregg wrote:

>> I, too have been noodling this. I've had sucess with taking care of all of
>> the reciprocity corrections at the time of exposure. I process normal.
>>
>> The whole thing about overexpose and under develop, or underexpose to over
>> develop never made sense to me as the conditions under which I shoot could
>> change mid-roll.
>>
>> gregg mcneill

I tried to send earlier today a message I got from a guy at Ilford about
this, but it bounced. I'll try again:

> From: "David A Carper" <David.Carper@ilford.com>
> To: "Shannon Stoney" <shannonstoney@earthlink.net>
> Subject: Re: Reciprocity failure and development times
> Date: Mon, Jun 24, 2002, 6:11 AM
>
>
> Within the range of times which we have tested, ILFORD films do not exhibit
> a sufficient change in contrast to warrant a recommended change in
> development.
> Obviously, if you are using longer times, or working with a very critical
> situation,
> you may find that you will need to modify the development time slightly
> (usually
> giving less development), but you will need to do some testing for your own
> particular situation.
>
> Regards,
> David Carper
> ILFORD Technical Service

I don't know what he means by "longer times." I guess he means longer than
the 200 seconds or so on the Ilford chart. I downloaded a PDF file that has
specs for HP5+ and it had a reciprocity failure graph chart.

I shoot sheet film so I do pay attention to exposure vs development for each
exposure, but as it turns out, it's unnecessary to make additional
corrections with HP5+ in development times for long exposures.

--shannon

----------
>From: "gregg b. mc neill" <gbmcneill@hotmail.com>
>To: pinhole-discussion@pinhole.com
>Subject: Re: [pinhole-discussion] reciprocity failure and development times
>Date: Mon, Jun 24, 2002, 6:55 AM
>

>
>
>>Sorry to have a one track mind, but I am still thinking about whether you
>>need to change your development times when you make long exposures. The
>>theory seems to be that highlights expose more than shadows during long
>>exposures, so that you should under-develop. But, when I do this the
>>highlights look too dull. I am wondering if this "rule" is really true.
>>What do other people on this list do? Do you develop less as you make
>>longer exposures?
>>
>>--shannon
>
>
> _________________________________________________________________
> Chat with friends online, try MSN Messenger: http://messenger.msn.com
>
>
> _______________________________________________
> Post to the list as PLAIN TEXT only - no HTML
> Pinhole-Discussion mailing list
> Pinhole-Discussion@pinhole.com
> unsubscribe or change your account at
> http://www.pinholevisions.org/discussion/
Received on Mon Jun 24 11:19:27 2002