Facial Skin Layered
Mapping
Part 7.0 – The Diffusion Map
Before You Begin
Have your work file open in Photoshop. Have your model open in AM.
Introduction
After light reflects off you model, the diffusion map
is the final map that it will pass through before it is seen by the
camera. This map makes all the
difference in the world. Without it the
amount of light that is reflected by a crack, wrinkle or pore or, hard skin or
soft skin is the same. The diffusion map
needs to contain information about ever detail but then we already have this.
- In
the Bump layer set, duplicate the Pore layer and drag it into the Diffuse
layer set above the Diffuse Base layer.
- Change
the Blend mode to Overlay.
- Do
Merge Down (<ctl>e).
- This
map contains all the information the Diffuse map needs so lets preserver
it by duplicating it, renaming the duplicate Diffuse Base Save and then
locking and hiding it. It should be
below the Diffuse Base layer.
- As
is this will create a very nice diffuse map adding much reality to all but
the deep wrinkles – these will be too dark. Ideally we keep the smoother and subtler
areas and decrease the wrinkles as well as all darker areas.
- Zoom
in and with the eye dropper select the darkest color you can find on the
image.
- Do
Select->Color Range.
Set the Fuzziness at zero and slowly increase it until only the
wrinkles and other darker areas are showing (Figure 7.0.1). Click Okay. Press <ctl>j to move this
selection to a new layer above this layer.

Figure 7.0.1
- Now do Adjustment->Brightness/Contrast and
adjust the Brightness to +35 or to where these dark areas are lowered to
where they are only slightly darker then the rest of the gray range
(Figure 7.0.2).

Figure 7.0.2
- Reduce the Opacity to 90%.
- Generate a new map, add it and change the map
type and also lower the map percentage.
Human skin tipically has a diffusion of 80% to 90% which, in AM and
the gray scale values in this map, means 10% to 20%. Start at 15% and test and adjust.
Go to Part 8.0 –
Tweaking the Maps