U of S | Mailing List Archive | alt-photo-process-l | Re: FILTER FACTOR FOR #52



according to the filter wheel I have (The negative Ansel Adams) #52 it's not
mentioned but as others have suggested a starting point of 6 or 7X would
seem reasonnable. A light meter or even a digital camera would also give you
a fair starting point but you need to remember that each film as a specific
response to light from a spectral point of view and this may translate to a
somewhat and may be significantly different filter factor. In the end this
mean that one should make a few test to make sure they have the right filter
factor for the film under consideration. If you intend to digitize your negs
you have much more room to play as long as your scanner can capture the
density range you end up with on the neg, in other word you can over expose
by as much as 3 stops if your scanner can read around 2.5D and even more
stops if it can read around or above 3D and you will still be able to use
the neg and edit the image to your satisfaction. But, if you use the negatif
in the traditional fashion, you need to capture the density range required
by you printing process, otherwise you may be unable to process and print
the neg correctly. The traditional fashion is much less forgivin them the
digital route as you surely know already.


----- Original Message -----
From: "BOB KISS" <bobkiss@caribsurf.com>
To: <alt-photo-process-l@usask.ca>
Sent: Wednesday, July 09, 2008 8:51 AM

> Thanks to all on Alt Photo who replied!
> -----Original Message-----
> From: Liam Lawless [mailto:lawless@bulldoghome.com]
> Sent: Wednesday, July 09, 2008 12:01 AM
> To: alt-photo-process-l@usask.ca
> Subject: RE: FILTER FACTOR FOR #52
> Bob,
> When I forget the factors of the many filters I have kicking around here,
> simply put the offending piece of glass or resin in front of the window of
> my light meter and take a reading... then another without a filter.  Works
> pretty good!
> Wikipedia has an entry for 'Wratten Number' that lists all the commonly
> available Wrattens, and 52 ain't there.  Neither is it in the 'Filter
> Substitution Table' in Wall & Jordan, where they have Wratten 11 and 23A
> light green (and 13 as medium green).  No factors, though.
> Liam
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