Modification, also called "modding," is the act of altering the face or body of the doll. Modification usually implies that the changes are permanent, and irreversible changes; however, there are a few temporary additive changes that are occasionally referred to as modification..
Additive vs. Subtractive Modification
Additive modification involves adding new material to an existing doll. The most common additive modifications are closing a doll's eyes by sculpting an eyelid or adding pointed tips to create elf ears.
Pros of Additive Modification
- It may be possible to remove the new material, so this sort of modification is more reversible.
- There is no limit to the amount of material that can be added, so there are no restrictions to the degree of modification possible.
Cons of Additive Modification
- Improper color matching can lead to unsightly differences in color between the modification and the resin.
- Differences in translucency between the new material and resin make additions visible unless they are airbrushed, even with correct color matching.
- Additive modifications are more prone to breakage than resin of the same thickness.
- Most additive materials are heavier than resin; large additions (such as breast enlargement) may unbalance the doll and affect poseability.
Subtractive modification is the removal of resin to alter the appearance. The most common subtractive modification is enlarging or reshaping the eyes by removing part of the eyelid. Other commonly reshaped areas are the nose, jawline, and breasts.
Common tools include a craft knife (such as Xacto), rotary tool (such as a Dremel), and sandpaper of varying grits.
Pros of Subtractive Modification
- Because no material is added, there is no color-matching to be done.
- Subtractive modifications are less likely to break.
- The tools are commonly available.
Cons of Subtractive Modification
- Subtractive modifications are not reversible without adding new materials.
- Some resins have color differences between the surface and newly exposed inner resin that may make even well-finished modifications visible. This is especially true of tan-skin dolls, where even light sanding can expose the lighter-colored resin beneath.
- In poorly cast dolls, cutting into the resin may reveal flaws such as inclusions or air bubbles.
- (Unsubstantiated) Areas that have been sanded may yellow more quickly than unsanded area.
In recent years, temporary scars have been a popular modification.
For these modifications, a customizer may use an acrylic texture paste (or even craft glue) to create raised areas on the resin. These are removable with acetone or other thinners.
Resin is a type of plastic and does not naturally biodegrade. Because of this, resin dust that is inhaled may accumulate in the lungs.
It is recommended that customizers wear a mask or respirator when sanding resin. Sanding underwater (such as by keeping the pieces submerged in a bucket of water while sanding) will also help to keep the dust from entering the air.
Additionally, some resins may release toxic fumes when sanded; it is recommended that sanding be done in a well-ventilated area.
Well-done, aesthetically pleasing modifications can raise the value of a doll. However, poorly done or very character-specific modifications can considerably lower the resale value of a doll.
In most cases, modifications to a limited doll will lower the value of the doll to other collectors.
In the doll community, there is an expectation that any modifications will be disclosed in the terms of sale; undisclosed modifications can be grounds for serious complaints, loss of seller's reputation, or even financial repercussions.