By using various kinds of contrast masks, the traditional photographer can have far greater contrast control, from
subtle to extreme, on his prints than merely using standard methods such as paper grade or developer changes.
Contrast masking can also be used to affect contrast or brightness in localized areas of the image. Another great
benefit of contrast masking is that the original negative is never subjected to any potentially damaging or risky
chemical processes. In most cases the results of effective masking cannot be duplicated or even approached by
standard printing techniques. Contrast masking can be used in conjunction with variable contrast papers or different
developers to give the photographer practically limitless tools for easily achieving stunning print quality!
Among many professional photographers contrast masking has become the "buzz" word in recent years. This brief
discussion is focused on the use of photographic contrast masking in traditional black and white photography (not
digital). Many of these specialized photographic techniques can also be used for color printing to achieve amazing
print quality results. It is important to note that contrast masking is FAR MORE than just the Unsharp Mask!
Although I shot this 4x5 negative using an orange filter in hopes of increasing the separation between the
radiant clouds and sky, the values were still too close when printing with standard paper grades. I tried harder
paper grades only to find that the delicate clouds took on a harsh and grainy appearance and it was far more
difficult to achieve gentle and subtle values in the print overall. I made a type 2 Fog Mask which worked
beautifully in darkening the sky values without affecting the bright clouds at all. I also did some burning and
dodging with this mask exposure to help emphasize the repeating cloud patterns and maintain a clean and balanced
print. A nice benefit from using this mask is that I could use a softer grade of paper to prevent the overall
values from being too harsh and minimize the appearance of grain in the sky. A type 1 Fog Mask (actually a
by-product of making the type 2 Fog Mask) was used to darken and even-out the values towards the bottom of the
print.
What is a contrast mask?
A photographic contrast mask is typically a sheet of film (usually made by contacting the original negative on it in
various ways) placed against the original negative when printing, or printed separately after the original negative
is printed.
There are three basic types of contrast masks:
Sandwich type masks
These are designed to be placed against the original negative (usually on top of the original negative) so that
the images of both original negative and contrast mask are "aligned" or registered. The print is then exposed
using this negative/mask sandwich. Since this is a negative-plane mask, you can make any size print at any time
without having to remake the contrast mask. Examples of these are Unsharp Masks, Contrast Reduction Masks,
Highlight Masks, Dodge Masks and other special masks for increasing contrast. Except for the Highlight Mask,
these can be registered by eye, but a pin-registration system is very helpful to insure accuracy and speed, and
is usually required for Highlight Masks.
Separate Exposure type masks
These are designed to be printed separately from the original negative exposure. The "mask exposure" that is
given to the printing paper is usually done after the main (original negative) exposure is given to the paper.
Examples of these are Shadow Contrast Increase Masks, Fog Masks (both type 1 and 2) and in some cases Dodge
Masks (if used for a totally different effect than when sandwiched). A good pin-registration carrier system (see
www.MaskingKits.com) is a MUST for all separate
exposure type masks. I use the Precision Pin-Registration Carrier System in all of my printing and masking work.
Paper-Plane type masks
These are placed on or near the surface of the printing paper either during the main print exposure, or after
the main print exposure. They are limited to making the exact same-size print every time, unless the mask is
re-made to fit a different size print. These masks must initially be aligned by eye prior to the printing
session. Once aligned, they can be pin-registered on or near the paper-plane so that re-alignment during the
course of the current printing session is not needed.
What mask does what?
Unsharp Masks
reduce the overall contrast of the original negative and enhance edge sharpness. The effect is very similar to
the digital unsharp mask filter in Adobe Photoshop (or other digital image manipulation software) and indeed the
digital counterpart adopted the name from these long-time traditional methods. A higher contrast paper grade is
usually necessary (even preferable) when using this mask in order to overcome the general flattening effect and
to increase the illusion of sharpness. When over-used, the effect of the unsharp mask can appear too "wired" (to
coin a phrase from photographer Dennis McNutt), giving the image an unnatural appearance. When used judiciously
however, it can open up detail in deep shadows and can result in a crisp print full of detail at the slight
expense of midtone contrast. An unsharp mask is actually a form of contrast reduction mask designed to enhance
the sharpening effect.
Contrast Reduction Masks
raise the general shadow values of the image so that detail in dark shadows is not lost. Upper midtones and
highlights normally remain untouched. Edge sharpness is slightly enhanced, usually to a degree that is subtle
and seamless. The use of this mask does not normally require a higher contrast paper grade although sometimes it
can be helpful. These masks don't have quite as severe of a "flattening" effect on local detail in broad shadow
areas as pure Unsharp Masks sometimes do. Because of that, this is a preferable mask to use instead of the
Unsharp Mask when a sharpness enhancement is not of primary concern. Modern litho films, particularly Arista
APHS sold by Freestyle Photo, are perfect materials for contrast reduction masks as the abrupt shouldering
effect of litho films is extremely beneficial to the appearance of the final photographic print (this material
will prevent excessive detail flattening in the final print).
Highlight Masks
add density and contrast to the highlight values of the negative. This results in an increase in the brilliance
and contrast of highlights in the print. The result is usually seamless and can be quite striking, making it
possible to achieve crisp, luminous glowing highlights without affecting the other values of the photograph. It
can easily be customized to affect only certain highlights while leaving others untouched.
Dodge Masks
are usually placed in sandwich with the original negative when exposing the print. Handmade dodge masks require
sketching or painting on a sheet of clear film or Mylar in the areas you wish to dodge. A textureless diffusion
material (Duratrans or Fujitrans is the ideal substance) is used in the glass carrier as a diffuser to soften
the edges of the mask so that it's effect is seamless on the print. Inkjet dodge
masks, made with the computer and an inkjet printer, represent the ultimate in dodge
masking, and can even mimic the effect of a highlight mask or contrast reduction mask at times.
Shadow Contrast Increase Masks
enhance the depth of fine black detail in the print. This may very well be the "king" of all photographic masks
and was "discovered" in the late 1980's by Dr. Dennis McNutt and Mark Jilg. It can be used to overcome any
flattening effects from the use of Unsharp Masks or Contrast Reduction Masks. It can also be used in conjunction
with softer paper grades to bring life into otherwise dull shadows. It can be used in conjunction with dodging
as well, enhancing the luminosity of dodged shadow or lower midtone areas by helping to "key" the shadow values
of the print with fine black accents. These masks require a precise pin-registration system in the enlarger. See
www.MaskingKits.com. The effect of this mask is
beautifully seamless and can end the persistent problem of dull, flat, lifeless shadows. It can help create very
tactile and visually stunning shadow values.
Fog Masks
are extremely useful masks as well. This method of precision flashing will diminish the brightness of
distracting highlights or bright spots on the photograph, such as a bright sky filtering through tree branches
in a forest scene, or a bright rock in an area of the print that might distract the viewer. It can also darken
skies and smooth-out uneven sky values. It is extremely useful as a local fogging tool, and because it is a
photographic method (not hand-made), precise flashing can be done without affecting adjacent areas. The effect
is seamless if not over-done, and its use can contribute to a smooth and eloquent photograph. It is probably the
easiest mask to make and use but it requires a pin-registration carrier system. A variation of this mask called
a type 2 Fog Mask is used to darken and smooth-out midtone areas of an image while protecting bright areas, such
as clouds.
Paper-Plane Masks
are large sheets of either photographic film or other material which are placed on or slightly above the paper
surface. These can be made by hand or by actually exposing large sheets of film. Depending on how they are made,
they have different uses. The most common use is localized flashing or fogging of specific areas of the print.
There are some limitations to this type of mask, most notably that each is custom made for a specific print
size. This masking technique is particularly useful when printing small format negatives.
At first glance it may sound like photographic contrast masking is difficult and time consuming. Quite the opposite
is true. Anyone can make effective masks of any type as long as the basics are learned. With even a little
experience, these methods can become quite intuitive, just like printing! And - a densitometer is not necessary for
any of these procedures! Freestyle Photo's Arista APHS litho film is the perfect film for all kinds of masks. This
film is capable of attaining extreme contrast and density required for masks such as Shadow Contrast Increase Masks
and type 2 Fog Masks, yet it can also achieve very soft contrast required for masks such as Unsharp Masks. Dektol or
similar paper developers, in various dilutions from 1:1 to as much as 1:50 or more (stock developer to water) can be
used for developing this film to make any of the above masks. It is a remarkable, versatile and cost-effective
product.