[pure-silver] Re: Kodak vs Ilford

  • From: "mail1" <mail1@xxxxxxxxxxxxxxxxx>
  • To: <pure-silver@xxxxxxxxxxxxx>
  • Date: Sun, 23 Mar 2008 21:06:48 -0700

I use Ilford Ortho plus for black and white masking. It is very easy to work
with under a red safe light.

Jonathan Ayers [mail1@xxxxxxxxxxxxxxxxx]

-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Richard Knoppow
Sent: Sunday, March 23, 2008 5:41 PM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Kodak vs Ilford

At 05:19 PM 3/23/2008, you wrote:
>Bob Pace, with 50 years of experience, years ago developed masking
>techniques for "Gasper Color", which was the fore runner of Cibachrome, has
>written a self published book "Masking for Photographic Processes" This
book
>is a very practical approach.
>
>Knut Kvistad self published a book "Photocomposition, A reference guide"
>This book gets into some of the more esoteric use of masking.
>
>David Doubley self published a book "The Dye Transfer Process"
>This book really explores the techniques of Masking
>
>Howard Bond wrote a definitive series of articles for "Darkroom Techniques"
>The collection presents a detailed discussion of masking in relation to
>Black and white photography. A visit to phototechmag.com
>Might be a source of reprints, and back issues of Howard Bond's articles.
>
>Lynn Radeka wrote a chapter in "Way Beyond Monochrome" about masking
>techniques, then he self published "Contrast Masking Kit" A compilation of
>masking techniques and special procedures. Parts of this originally
appeared
>in Darkroom and Creative Camera Techniques 1989 issues July-August
"Contrast
>Reduction Masks", September-October "Shadow Contrast Increase Masks",
>November-December "Highlight Masks" by Mark Jilg and Dennis McNutt. These
>articles present a great overview with great photos.
>
>
>David Malin wrote a ten page article in Kodak's "techbits" issue #1 1990 on
>image enhancement using unsharp masks.
>
>Barry Thornton's book "Edge of Darkness" chapter 13 "The Mask of Sorrow"
>Eloquently writes about his experiences with masking.
>
>These authors cover the subject well, from the very simple calibrated by
the
>eye ball method to the very exact.
>
>Jonathan Ayers [mail1@xxxxxxxxxxxxxxxxx]

     Thank you, I would not have remembered all these references 
although I am familiar with them.
      Masking for contrast reduction is relatively simple, relatively 
being the operative adverb. If a linear material is used for the mask 
the overall contrast is reduced but the actual curve shape of the 
original can be changed by mask which is not linear in some fashion. 
For instance, highlight contrast can be reduced without much 
affecting the rest of the image by making a mask with relatively high 
contrast and exposed so that only the highlight portion has much density.
      There is another, and much more complex, system of masking used 
for color. These masks are used to correct errors in the color 
filtering of the original and the transmission of the dyes or 
pigments used for printing. Modern color negative materials have a 
self-masking system built-in. The masks are generated automatically 
by using color couplers (the substances that become dye) which are 
themselves colored. When the coupler is converted to dye it changes 
color to the color required by the particular color layer. This 
leaves a positive image in the mask color embedded in the color 
image. The mask color is chosen to neutralize transmission of the 
color of the image by spurious color transmission from the dyes in 
other layers. Most color films contain colored couplers in two of the 
layers. This is why the clear areas of the negative have an orange 
cast. This method of masking is obviously not useable for positive 
images for direct viewing although it _could_ be used for positives 
meant only for duplication. Another, more recent method of masking 
and one used in both positive and negative materials, makes use of an 
interaction between layers. Development in one layer produces 
reaction products which are allowed to migrate to adjoining layers to 
affect the degree of dye generation. Some modern negative color films 
make use of both methods.
       The reason for this masking is that the unwanted transmission 
results in the reduction of color purity and saturation.  Very 
elaborate masking was used for four-color photo-mechanical printing 
to compensate for the ink spectrum. These masks are still used by are 
now generated electronically.
       I should also mention un-sharp masks. These are contrast masks 
which are either exposed or printed in such a way (for instance 
exposing and printing through the support side) that the mask image 
is blurred. The effect is to lower overall contrast with little 
effect on small details. This results in an enhancement of acutance 
or edge sharpness so that textures, etc., look sharper. Since the 
mask is less critical of exact positioning than a sharp mask the 
method was quite widely used for Cibachrome printing.
      Kodak used to make a special film for masking as a component of 
their dye transfer method but all of the dye transfer materials were 
discontinued several years ago. A good substitute is T-Max100 film 
which can be very fine grain and has a suitable spectral response for 
color work.


--
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.

No virus found in this incoming message.
Checked by AVG. 
Version: 7.5.519 / Virus Database: 269.21.8/1339 - Release Date: 3/22/2008
4:43 PM
 

No virus found in this outgoing message.
Checked by AVG. 
Version: 7.5.519 / Virus Database: 269.21.8/1339 - Release Date: 3/22/2008
4:43 PM
 

=============================================================================================================
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: