diff --git a/README.md b/README.md
index f431c6c..45f28a0 100644
--- a/README.md
+++ b/README.md
@@ -118,6 +118,28 @@ res_img = img.max(img2)
 
 ```
 
+## Contrast operations
+
+Contrast types are defined in the Contrast enumeration:
+
+```
+floatimg.Contrast.SQRT
+floatimg.Contrast.POW2
+floatimg.Contrast.COS01
+floatimg.Contrast.COS010
+```
+
+To apply contrast:
+
+```
+# Return a new image
+res = img.contrast(value, floatimg.Contrast.SQRT)
+
+# set contrast in-place
+img.contrast(value, floatimg.Contrast.SQRT, True)
+```
+
+
 
 ## Development
 
diff --git a/floatimg/__init__.py b/floatimg/__init__.py
index b765067..61beb52 100644
--- a/floatimg/__init__.py
+++ b/floatimg/__init__.py
@@ -10,6 +10,7 @@ from floatimg.image import (
     create_from_dump,
     create_from_png,
     fileinfos,
+    Contrast
 )
 
 __version__ = "0.0.1"
diff --git a/floatimg/image.py b/floatimg/image.py
index 248001e..4bc696f 100644
--- a/floatimg/image.py
+++ b/floatimg/image.py
@@ -1,4 +1,7 @@
+"""Binding bases"""
 import ctypes as ct
+from enum import Enum
+import logging
 
 from floatimg.settings import LIB, PATH_ENCODING
 
@@ -9,6 +12,16 @@ RGB = 3
 RGBA = 4  # may not be used
 RGBZ = 99  # may not be used
 
+############################################################################################################
+# Contrast enumeration
+class Contrast(Enum):
+    NONE = 0
+    SQRT = 1
+    POW2 = 2
+    COS01 = 3
+    COS010 = 4
+
+
 ############################################################################################################
 # Type mapping
 class C_FloatImg(ct.Structure):
@@ -33,6 +46,8 @@ C_FloatImg._fields_ = [
 
 ############################################################################################################
 # declaration of input / output types for C binding of core functions
+
+# fimg-core.c
 c_fimgcreate = LIB.fimg_create
 c_fimgcreate.argtypes = (ct.POINTER(C_FloatImg), ct.c_int, ct.c_int, ct.c_int)
 c_fimgcreate.restype = ct.c_int
@@ -99,6 +114,7 @@ c_fimg_rgb_constant.argtypes = (
 )
 c_fimg_rgb_constant.restype = ct.c_int
 
+# fimg-file.c
 c_fimg_dump_to_file = LIB.fimg_dump_to_file
 c_fimg_dump_to_file.argtypes = (ct.POINTER(C_FloatImg), ct.c_char_p, ct.c_int)
 c_fimg_dump_to_file.restype = ct.c_int
@@ -122,7 +138,7 @@ c_fimg_add_rgb.argtypes = (
 )
 c_fimg_add_rgb.restype = ct.c_int
 
-# operators
+# # fimg-operators.c
 c_fimg_add_3 = LIB.fimg_add_3
 c_fimg_add_3.argtypes = (
     ct.POINTER(C_FloatImg),
@@ -180,6 +196,35 @@ c_fimg_get_maxvalue = LIB.fimg_get_maxvalue
 c_fimg_get_maxvalue.argtypes = (ct.POINTER(C_FloatImg),)
 c_fimg_get_maxvalue.restype = ct.c_float
 
+# contrast
+c_fimg_square_root = LIB.fimg_square_root
+c_fimg_square_root.argtypes = (
+    ct.POINTER(C_FloatImg),
+    ct.POINTER(C_FloatImg),
+    ct.c_double,
+)
+c_fimg_square_root.restype = ct.c_int
+
+c_fimg_power_2 = LIB.fimg_power_2
+c_fimg_power_2.argtypes = (ct.POINTER(C_FloatImg), ct.POINTER(C_FloatImg), ct.c_double)
+c_fimg_power_2.restype = ct.c_int
+
+c_fimg_cos_01 = LIB.fimg_cos_01
+c_fimg_cos_01.argtypes = (ct.POINTER(C_FloatImg), ct.POINTER(C_FloatImg), ct.c_double)
+c_fimg_cos_01.restype = ct.c_int
+
+c_fimg_cos_010 = LIB.fimg_cos_010
+c_fimg_cos_010.argtypes = (ct.POINTER(C_FloatImg), ct.POINTER(C_FloatImg), ct.c_double)
+c_fimg_cos_010.restype = ct.c_int
+
+# contrast function map
+CONTRAST_FUNC_DICT = {
+    Contrast.SQRT: c_fimg_square_root,
+    Contrast.POW2: c_fimg_power_2,
+    Contrast.COS01: c_fimg_cos_01,
+    Contrast.COS010: c_fimg_cos_010,
+}
+
 ############################################################################################################
 class FloatImg:
     """
@@ -212,6 +257,7 @@ class FloatImg:
     #######################################################################################################
     def destroy(self):
         """destroy the underlying structure. automattically called at instance destruction"""
+        logging.debug("Destroy %s", self)
         assert c_fimg_destroy(self.c_img) == 0
 
     #######################################################################################################
@@ -322,7 +368,6 @@ class FloatImg:
         assert c_fimg_minimum(self.c_img_p, img.c_img_p, res.c_img_p) == 0
         return res
 
-
     #######################################################################################################
     def max(self, img):
         """return a new image with maximum pixel values per channel between current and parameter"""
@@ -346,6 +391,18 @@ class FloatImg:
         """return the maximum value for any channel in the image"""
         return c_fimg_get_maxvalue(self.c_img_p)
 
+    #######################################################################################################
+    def contrast(self, max_value, contrast_id=Contrast.SQRT, in_place=False):
+        """"""
+        func = CONTRAST_FUNC_DICT[contrast_id]
+        dest = None
+        dest_c_img = None
+        if not in_place:
+            dest = self.clone(False)
+            dest_c_img = dest.c_img_p
+        assert (func(self.c_img, dest_c_img, max_value)) == 0
+        return dest
+
 
 ###########################################################################################################
 def fileinfos(fname):
diff --git a/tests/contrast.py b/tests/contrast.py
new file mode 100644
index 0000000..0c40ba3
--- /dev/null
+++ b/tests/contrast.py
@@ -0,0 +1,35 @@
+import floatimg
+import logging
+
+
+def test_square():
+    width, height = 5, 5
+
+    color = [127.0, 127.0, 127.0]
+    img = floatimg.create_rgb(width, height)
+    img.fill(color)
+    img.put(2, 2, [200, 200, 200])
+
+    result_dict = {
+        floatimg.Contrast.SQRT: (
+            [225.83180236816406, 225.83180236816406, 225.83180236816406],
+            [179.9583282470703, 179.9583282470703, 179.9583282470703],
+        ),
+        floatimg.Contrast.POW2: (
+            [156.8627471923828, 156.8627471923828, 156.8627471923828],
+            [63.250980377197266, 63.250980377197266, 63.250980377197266],
+        ),
+        floatimg.Contrast.COS01: (
+            [226.83277893066406, 226.83277893066406, 226.83277893066406],
+            [126.71460723876953, 126.71460723876953, 126.71460723876953],
+        ),
+        floatimg.Contrast.COS010: (
+            [100.2235336303711, 100.2235336303711, 100.2235336303711],
+            [254.99032592773438, 254.99032592773438, 254.99032592773438],
+        ),
+    }
+
+    for contrast_type, (center, outer) in result_dict.items():
+        res = img.contrast(255, contrast_type)
+        assert res.get(2, 2) == center
+        assert res.get(2, 3) == outer