diff --git a/JFSphoto.py b/JFSphoto.py
index 3ca3008..0699c07 100644
--- a/JFSphoto.py
+++ b/JFSphoto.py
@@ -564,18 +564,48 @@ class Jfsphoto (object):
             self.ax1.plot(t, s, linewidth=0.6)
         self.canvas.draw()
 
+    def check_requirement(self):
+        ok = True
+        if self.nm_checked.get() == 0:
+            ok = False
+            tk.messagebox.showerror('[nm]','You need to check calibration [nm]\n or first calibrate the instrument')
+        else:
+            s=''
+            s1=''
+            if (self.darkline_checked.get()==0):
+                s = ' Please take a darkline messurement first \n'
+            if  (self.baseline_checked.get()==0):
+                s1 = ' Please take a baseline messurement first \n'
+            if (len(s1)>0 or len(s)>0):
+                ok = False
+                tk.messagebox.showerror('ToDos',s+s1)
+        return ok
+
     def do_methods(self,panel):
         
         def cb(event):
-            x = tree.selection()[0].split(' ')
-            nm = tree.item(x[0])["values"][1]
-            ## nm -> point
-            p = (nm - self.nm_left)*(1/self.nm_step)
-            print(f'nm {nm} point {p}')
-
-            #panel.bcollect.invoke()
-            #self.df['m1']=config.rxData16
-    
+            if self.check_requirement() == True:
+                # get selected and save values
+                name = tree.selection()[0]
+                val= tree.item(name)["values"]
+                # get parent for nm 
+                x = name.split(' ')
+                nm = tree.item(x[0])["values"][1]
+                ## nm -> point
+                p = int((nm - self.nm_left)*(1/self.nm_step))
+                #print(f'nm {nm} point {p}')
+                s1 = str(val[2])+' '+tree.item(x[0])["values"][2]
+                s = 'Is a Cuvet for '+x[0]+' in concentration\n of '+s1+' in the photometer ? '
+                if  tk.messagebox.askokcancel(title='Messurement', message=s):
+                    panel.bcollect.invoke()
+                    self.df['m1'] = config.rxData16
+                    d = self.df.iloc[p]['darkline']
+                    b = self.df.iloc[p]['baseline']
+                    w = self.df.iloc[p]["m1"]
+                    #print(d,b,w,d-w, np.log10(b/(d-w)))
+                    val[3]= np.log10(b/(d-w))
+                    tree.item(x, text=name,values=val)
+            
         
 
 
@@ -640,7 +670,7 @@ class Jfsphoto (object):
             stp = e6.get()/e5.get()
             for i in range(1,e5.get()+1):
                 na = e1.get()+' '+str(i)
-                tree.insert(e1.get(),'end',na,text= na ,values=(i,'',stp * (i),0.0))
+                tree.insert(e1.get(),'end',na,text= na ,values=(i,'',stp * (i),0.0),tags=('cb'))
             s= ",".join(str(x) for x in tree.item(e1.get())["values"])
             for items in tree.get_children(e1.get()):
                 ss = ",".join(str(x) for x in tree.item(items)["values"] if len(str(x))>0)