At backside of Phra Somdej Wat Rakhang would have various characteristic of traces which occurred from
1. By equipment using when scraping off or pressing at backside.
2. By natural shrinkage and drying of amulet texture
Unique characteristic of traces caused from equipment which are oftenly seen in Phra Somdej Wat Rakang
1. Trace from betel leaf : in Thai called "Roi Kabmark". The small lines in vertical or horizontal depending on direction of placing the leaf at backside of amulet, then squeezed in order to make it tighten equally to mould. After removing betel leaf out, trace was seen from betel leaf such in pictures.
Betal Leaf Trace
2. Trace from wood plank : in Thai called "Roi Kradan" causing from bringing wood plank placed at backside of amulet and then squeezing to make it tighen. After removing wood plank out, trace on wood plank would be appeared on backside.
Wood Plank Trace
3. Trace from fine teeth of comb : in Thai called "Roi Whee Sanieat" causing decoration at backside by using teeth of comb. Ancestor believed that using teeth of comb for protection from bad evils. Trace can be appeared in vertical or horizontal and lines are bigger than betel leaf trace.
Fine teeth of comb trace
4. Trace from knife : causing from scraping for decoration at backside to be smooth by using knife.
4.1 If processing when texture was too much drying, knife will be stumble and not smooth which appeared twist trace with spacing in step by step as ladder, in Thai called "Roi Bandai" 
Stumble by knife trace
4.2 If scraping by knife when texture was still moist, soft and not dry, texture will be smooth backside or in Thai called "Lank Reab".
Smooth backside
4.2.1 Trace from rolling of hard grain materials : causing from scraping decoration at backside to be smooth by knife and some hard grain material were rolled on surface while texture still wet then, occurred rolling trace look comparatively like crab climbing in Thai called "Roi PooTai"
Rolling of hard grain materials trace which look comparatively like crab climbing
5. Sweeping Trace : Mould for Somdej Wat Rakang were carved from strong rock of some kinds. The Somdejs had been made by impression - to - mold process, their backside were leveled or flattened by sweeping with a small trowel. After the amulets had been brought out from the mould, four extension wings of them were cut by bamboo knife or "Tok" This is why the sweeping trace is seen on every good-conditioned Somdej Wat Rakang. The edge cracks caused by trowel sweeping.
Four extension wings were cut by bamboo knife
Crack at the edges caused by leveling or flattening effort using a small trowel.
Unique characteristic of trace caused from natural shrinkage and drying of texture
1. Porous : causing from
* Decay of natural organic materials and falling out by aging process. This occurred porous holes on surface
* Chemical reaction between shell lime and water while amulet still wet which emitted air bubble from inside. When texture was dried, it remained porous on surface
Porous
2. Natural Shrinkage Trace : causing from drying and shrinkage of amulet texture by aging process which occurred splitting off texture on surface in shallow track. Likely, worm is biting the fruit and making shallow track on fruit pulp, in Thai called this trace "Roi Nondont" (worm biting fruit)
Natural shrinkage in shallow track which look comparatively like biting mark in fruit pulp by worn
3. Small Holes : causing from decay of organic material mixtures by aging process e.g., pieces of fruit or small piece of solid materials e.g minerals, etc were falling off which made surfuce being small holes. Likewise, the hole on moon so, in Thai called "Moon Holes" 
Small holes from falling off materials mixture which look comparatively like holes on the moon surface
4. Wrinkle Trace : Causing from shrinkage of texture when removing amulet out from mould despite it still wet. Once amulet was dried, surface would be shrinked and wrinkled which look like steamed custurd in Thai called "Roi Sangkayha". 
Wrinkle Trace which look comparatively like steamed custard
5. Splitting out Trace : Causing from flattening whole surface at backside by using wood firstly, and next step bamboo knife was used to scrape both 2 sides before cutting edges. After dried, texture was shrinked and splitted out trace into 2 sides vertically from scraping decoration which look like trace of centipede feet when climbing on sand, in Thai called "Roi Teentakaab"
Split out trace which look comparatively like trace of centipede feet
CONCLUSION : BACKSIDE TRACES ARE NATURAL MARKINGS THAT HELP MUCH IN AUTHENTICATION
