[pure-silver] Re: Contrast paper developer

 Your are right. It is also true that my negative quite grainy when I complaint 
about contast. They are a little over exposed infared negatives. I plan to go 
back to my old condenser enlarger.

regards


Ibrahim Pamuk

  


-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx 
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Richard Knoppow
Sent: Thursday, August 16, 2007 12:23 AM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Contrast paper developer

De: Ä°brahim Pamuk <ibrahim.pamuk@xxxxxxxxxxxxx>
Date: Wed, 15 Aug 2007 11:54:01 +0300
Sujet: [pure-silver] Re: Contrast paper developer
À: <pure-silver@xxxxxxxxxxxxx>

>Hi,

Just one more question, I suppose your condenser enlarger uses a tungsten bulb 
and your diffused enlarger a halogen bulb, am I right ?


Good luck,
Claudio Bonavolta

   I don't thin this would make much difference. 
Tungsten-halogen lamps generally run at about the same temperature as plain 
tungsten. Tungsten enlarging lamps generally are around K3000. The color 
temperature of household tungsten lamps varies with the wattage but is around 
K2950 on average. Standard lamps for color photography are K3200. Photoflood 
lamps are around 3400 but get this high temperature because they are run 
overvoltage and have very short lives.
   AFAIK, no color enlarger has other than tungsten lamps. A cold light lamp, 
particularly the older very blue variety, will seriously limit the range of 
contrast available with variable contrast paper even when a yellow correction 
filter is used.
   The difference in printing contrast between a diffuse source, such as a 
color head with a mixing chamber, and a partially diffusing condenser enlarger, 
such as the typical Omega or Besler, is about one paper grade, but this also 
depends a bit of the grain of the negative. For instance, color negatives have 
virtually the same contrast for both types of sources. The difference in 
contrast comes from the scattering of light by the silver particles, the 
coarser the grain the greater the scattering. This is known as the Callier 
effect.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx


=============================================================================================================
To unsubscribe from this list, go to www.freelists.org and logon to your 
account (the same e-mail address and password you set-up when you subscribed,) 
and unsubscribe from there.

Other related posts: