Re: Pictorico Bummer

Judy,

Each density difference of log 0.10 is about 1/3rd of a stop, so a
difference of log .20 is 2/3rd of a stop.

Exposure is based on shadow density. So, assume that you had one
negative (Negative A) with a shadow density ready of log .10, and
you know the exposure that makes a perfect print. Now, if you have
another negative (Negative B) with a shadow density value of log
.30, you know that it will need 2/3rd of a stop more exposure.

Assume that the correct exposure for Negative A was 60 seconds.
Negative B will need 2/3 of a stop more exposure, or 100 seconds. A
1/3 stop increase would be 20 seconds, a 2/3 stop increase 40
seconds, and a full stop increae would be 60 seconds.

This applies to all negatives, in-camera or digital negatives.
Unfortunately, you need a UV densitometer to make this type of
reading when working with UV processes. But you can get around it by
test printing step wedges.

Best,

Sandy

>So....how is that done, Sandy? Applying a +2/3 log density
>difference, that is. I know how to try to pry one sheet into two as
>I just recently purchased my first box of Pictorico and my first
>though was, "Gee, this is thick stuff." Or are you talking about
>something other than a digineg?
>
>Thanks!
>Judy
>
>--
>Judy Rowe Taylor
>Mukilteo, WA
>Art is a voice of the heart, a song of the soul.
>www.enduringibis.com
>jude.taylor@comcast.net or judyrowetaylor@enduringibis.com
>
>
>
>
>
>Date: Sat, 20 Aug 2005 04:07:17 +0000
>From: Sandy King <sanking@clemson.edu>
>Subject: Re: Pictorico Bummer
>To: alt-photo-process-l@sask.usask.ca
>MIME-version: 1.0
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>
>2 sheets stuck together? Mark, Mark!! But you know, I tried to pry
>the piece apart because my first thought when I pulled the sheet
>from the package was that it had to be two pieces stuck together.
>But alas, not.
>
>Nope, one really thick sheet, and the other 14 sheets in the package
>are just as thick.
>
>The good news is that I just applied the log correction of +2/3 more
>stop indicated by the UV density difference of 0.20 and the print
>was perfect. Long exposure, but at least the overall density range
>is not different so one can still base exposures on a UV shadow
>density reading.
>
>Sandy
>
>
>
>
>
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>>Sandy,
>>
>>Boy that is a bummer-are you sure you don't have 2 sheets stuck together?
>>
>>I bought a bunch of it quite some time ago in both 8.5 x11 and 13 x
>>19 , so I am still going through that stock.
>>
>>Mark Nelson
>><http://www.precisiondigitalnegatives.com/>Precision Digital Negatives
>>
>>In a message dated 8/19/05 8:49:49 PM, sanking@clemson.edu writes:
>>
>>>I just opened a new box of 13X19" Pictorico and made a negative this
>>>evening. I noticed that the stock was quite a bit thicker than the
>>>previous stock of 13X19" material that I had been using so I decoded
>>>to take a reading of the UV base with my densitometer. It measures a
>>>full log .20 more than the old stock, .16 versus .37.
>>>
>>>What a pain. I have been basing my printing on first making a smaller
>>>negative on 8.5X11" material and then honing in exposure before
>>>making a larger one on 13X19", and getting perfect exposures. That is
>>>now no longer possible due to the change of stock.
>>>
>>>Anyone know if the the thickness of the 8.5X11" is still the same?
>>>
>>>
>>>Sandy
Received on Sat Aug 20 20:47:37 2005