diff --git a/coretk/coretk/dialogs/colorpicker.py b/coretk/coretk/dialogs/colorpicker.py
new file mode 100644
index 00000000..ded652a0
--- /dev/null
+++ b/coretk/coretk/dialogs/colorpicker.py
@@ -0,0 +1,150 @@
+"""
+custom color picker
+"""
+import logging
+import tkinter as tk
+from tkinter import ttk
+
+from coretk.dialogs.dialog import Dialog
+
+
+class ColorPicker(Dialog):
+    def __init__(self, master, app, initcolor="#000000"):
+        super().__init__(master, app, "color picker", modal=True)
+        self.red_entry = None
+        self.blue_entry = None
+        self.green_entry = None
+        self.hex_entry = None
+        self.display = None
+
+        self.red = tk.StringVar(value=0)
+        self.blue = tk.StringVar(value=0)
+        self.green = tk.StringVar(value=0)
+        self.hex = tk.StringVar(value=initcolor)
+
+        self.draw()
+        self.set_bindings()
+
+    def draw(self):
+        edit_frame = ttk.Frame(self)
+        edit_frame.columnconfigure(0, weight=4)
+        edit_frame.columnconfigure(1, weight=2)
+        # the rbg frame
+        frame = ttk.Frame(edit_frame)
+        frame.columnconfigure(0, weight=1)
+        frame.columnconfigure(1, weight=4)
+        frame.rowconfigure(0, weight=1)
+        frame.rowconfigure(1, weight=1)
+        frame.rowconfigure(2, weight=1)
+        label = ttk.Label(frame, text="R: ")
+        label.grid(row=0, column=0)
+        self.red_entry = ttk.Entry(
+            frame,
+            textvariable=self.red,
+            validate="key",
+            validatecommand=(self.app.validation.rgb, "%P"),
+        )
+        self.red_entry.grid(row=0, column=1, sticky="nsew")
+
+        label = ttk.Label(frame, text="G: ")
+        label.grid(row=1, column=0)
+        self.green_entry = ttk.Entry(
+            frame,
+            textvariable=self.green,
+            validate="key",
+            validatecommand=(self.app.validation.rgb, "%P"),
+        )
+        self.green_entry.grid(row=1, column=1, sticky="nsew")
+
+        label = ttk.Label(frame, text="B: ")
+        label.grid(row=2, column=0)
+        self.blue_entry = ttk.Entry(
+            frame,
+            textvariable=self.blue,
+            validate="key",
+            validatecommand=(self.app.validation.rgb, "%P"),
+        )
+        self.blue_entry.grid(row=2, column=1, sticky="nsew")
+
+        frame.grid(row=0, column=0, sticky="nsew")
+
+        # hex code and color display
+        frame = ttk.Frame(edit_frame)
+        frame.columnconfigure(0, weight=1)
+        label = ttk.Label(frame, text="Selection: ")
+        label.grid(row=0, column=0, sticky="nsew")
+        self.hex_entry = ttk.Entry(
+            frame,
+            textvariable=self.hex,
+            validate="key",
+            validatecommand=(self.app.validation.hex, "%P"),
+        )
+        self.hex_entry.grid(row=1, column=0, sticky="nsew")
+        self.display = ttk.Label(frame, background="white")
+        self.display.grid(row=2, column=0, sticky="nsew")
+        frame.grid(row=0, column=1, sticky="nsew")
+
+        edit_frame.grid(row=0, column=0, sticky="nsew")
+
+        # button frame
+        frame = ttk.Frame(self)
+        frame.columnconfigure(0, weight=1)
+        frame.columnconfigure(1, weight=1)
+        button = ttk.Button(frame, text="OK", command=self.button_ok)
+        button.grid(row=0, column=0, sticky="nsew")
+        button = ttk.Button(frame, text="Cancel", command=self.destroy)
+        button.grid(row=0, column=1, sticky="nsew")
+        frame.grid(row=1, column=0, sticky="nsew")
+
+    def set_bindings(self):
+        self.red_entry.bind("<FocusIn>", lambda x: self.current_focus("rgb"))
+        self.green_entry.bind("<FocusIn>", lambda x: self.current_focus("rgb"))
+        self.blue_entry.bind("<FocusIn>", lambda x: self.current_focus("rgb"))
+        self.hex_entry.bind("<FocusIn>", lambda x: self.current_focus("hex"))
+        self.red.trace_add("write", self.update_color)
+        self.green.trace_add("write", self.update_color)
+        self.blue.trace_add("write", self.update_color)
+        self.hex.trace_add("write", self.update_color)
+
+    def button_ok(self):
+        logging.debug("not implemented")
+
+    def get_hex(self):
+        red = self.red_entry.get()
+        blue = self.blue_entry.get()
+        green = self.green_entry.get()
+        return "#%02x%02x%02x" % (int(red), int(green), int(blue))
+
+    def current_focus(self, focus):
+        self.focus = focus
+
+    def update_color(self, arg1, arg2, arg3):
+        if self.focus == "rgb":
+            red = self.red_entry.get()
+            blue = self.blue_entry.get()
+            green = self.green_entry.get()
+            if red and blue and green:
+                hex_code = "#%02x%02x%02x" % (int(red), int(green), int(blue))
+                self.hex_entry.delete(0, tk.END)
+                self.hex_entry.insert(0, hex_code)
+                self.display.config(background=hex_code)
+        elif self.focus == "hex":
+            hex_code = self.hex.get()
+            if len(hex_code) == 4 or len(hex_code) == 7:
+                if len(hex_code) == 4:
+                    red = hex_code[1]
+                    green = hex_code[2]
+                    blue = hex_code[3]
+                else:
+                    red = hex_code[1:3]
+                    green = hex_code[3:5]
+                    blue = hex_code[5:]
+            else:
+                return
+            self.red_entry.delete(0, tk.END)
+            self.green_entry.delete(0, tk.END)
+            self.blue_entry.delete(0, tk.END)
+            self.red_entry.insert(0, "%s" % (int(red, 16)))
+            self.green_entry.insert(0, "%s" % (int(green, 16)))
+            self.blue_entry.insert(0, "%s" % (int(blue, 16)))
+            self.display.config(background=hex_code)
diff --git a/coretk/coretk/validation.py b/coretk/coretk/validation.py
index c7923229..955a7faf 100644
--- a/coretk/coretk/validation.py
+++ b/coretk/coretk/validation.py
@@ -15,6 +15,8 @@ class InputValidation:
         self.positive_float = None
         self.name = None
         self.ip4 = None
+        self.rgb = None
+        self.hex = None
         self.register()
 
     def register(self):
@@ -22,6 +24,8 @@ class InputValidation:
         self.positive_float = self.master.register(self.check_positive_float)
         self.name = self.master.register(self.check_node_name)
         self.ip4 = self.master.register(self.check_ip4)
+        self.rgb = self.master.register(self.check_rbg)
+        self.hex = self.master.register(self.check_hex)
 
     def ip_focus_out(self, event):
         value = event.widget.get()
@@ -100,7 +104,7 @@ class InputValidation:
                 return False
             for _8bits in _32bits:
                 if (
-                    (_8bits and int(_8bits) > 225)
+                    (_8bits and int(_8bits) > 255)
                     or len(_8bits) > 3
                     or (_8bits.startswith("0") and len(_8bits) > 1)
                 ):
@@ -108,3 +112,29 @@ class InputValidation:
             return True
         else:
             return False
+
+    def check_rbg(self, s):
+        if not s:
+            return True
+        if s.startswith("0") and len(s) >= 2:
+            return False
+        try:
+            value = int(s)
+            if 0 <= value <= 255:
+                return True
+            else:
+                return False
+        except ValueError:
+            return False
+
+    def check_hex(self, s):
+        if not s:
+            return True
+        pat = re.compile("^([#]([0-9]|[a-f])+)$|^[#]$")
+        if pat.match(s):
+            if 0 <= len(s) <= 7:
+                return True
+            else:
+                return False
+        else:
+            return False