Re: Dumb 4x5 copy lens question

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From: Ken Sinclair (photo1@telusplanet.net)
Date: 05/18/00-09:45:29 AM Z


Doug,

>* What focal length lens would I need to do copy work, probably copying
>prints in the 8x10" size, some smaller, some slightly larger.

For an 8x10 print to 4x5 copy negative you're looking at an approximate
0.5:1 magnification, which means that you will need a bellows extension of
~50% of the focal length of your installed lens (and ~1 stop) increase in
exposure from your indicated. While it might be "proper" to use a flat
field lens, I have been using either a 240 Grandagon, 150 and 210 Sironars
without any difficulties.

>any comments on this 4125 Pro Copy film, either?

Rate the 4125 at ISO 12 for tungsten, and process by time or inspection in
red safelight in HC110 dilution E... either tray (~4.5 min@ 20°C) or tank
(~6 min @20°C with agitation at 1 minute intervals) for the allotted
time... which will vary slightly (usually) depending on the paper that you
are going to print to. Exposures can be up to about 10-12 seconds without
running into receprocity failure.... I have gone to about 16-20 seconds on
occasions without running into noticeable problems

If you have not used 4125 in the past, I would respectably suggest that you
run some tests beforehand, to get your exposure/development "in control"
for the paper you will be printing to.

I have a friend who swears by Ilford Commercial (also an orthochromatic
film) for copy work... but I have not tried it.

Ken

[||/\/\/\/\/\/\|| Ken Sinclair RBP, FBPA
[|| ||-| Applied Photographic Services
[|| || | Lethbridge,
[|| || | Alberta, Canada,
[|| ||-| (403) 381-1654.
[||\/\/\/\/\/\/|| photo1@telusplanet.net
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