Get the original light / color in custom shader

Hi there, I am in a middle of doing something and I created a custom shader, complete out of chance (just changing lines of code, without knowing anything about shader scripting)! This shader is in combination with another material that is used as mask for my shader's material.

To set things straight:

• An object is rendered with a mask material. This material makes this object transparent on screen. Whatever object is being hidden by the 1st object in the scene, it is not visible to the camera, unless it is rendered with a material that uses my custom shader.

• My custom shader also applies green screen rejection (meaning anything is green, it is transparent.

• Finally I have to add that as texture I use "render texture" from another camera.

So I want the video (with green screen transparency) that is being revealed behind object1 to be at the same color that is in the captured video,and not darker or lighter.

This is the shader for the mask (applied on object 1):

 Shader "Stencils/Masks/StencilMask_1"
 {
     SubShader 
     {
         Tags { "RenderType"="Opaque" "Queue"="Geometry-100"}
         ColorMask 0
         ZWrite off
         Stencil 
         {
             Ref 1
             Comp always
             Pass replace
         }
         
         Pass
         {
         CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
             
             struct appdata 
             {
                 float4 vertex : POSITION;
             };
             
             struct v2f 
             {
                 float4 pos : SV_POSITION;
             };
             
             v2f vert(appdata v) 
             {
                 v2f o;
                 o.pos = UnityObjectToClipPos(v.vertex);
                 return o;
             }
             
             half4 frag(v2f i) : COLOR 
             {
                 return half4(1,1,0,1);
             }
         ENDCG
         }
     }
 }
 
  

And this is my custom shader:

 Shader "Custom/ChromaStenciled" {
 
     Properties{
         _MainTex("Base (RGB)", 2D) = "white" {}
     _AlphaValue("Alpha Value", Range(0.0,1.0)) = 1.0
         _Color("Main Color", Color) = (1,1,1,1)
 
     }
         SubShader{
         Stencil{
         Ref 1
         Comp equal
         Pass keep
         Fail keep
     }
         //Tags{ "RenderType" = "Transparent" }
         Tags{ "Queue" = "Transparent" "RenderType" = "Transparent" }
         LOD 200
 
         CGPROGRAM
 //#pragma surface surf Lambert
 #pragma surface surf Lambert alpha
 
         sampler2D _MainTex;
     fixed4 _Color;
     float _AlphaValue;
 
     struct Input {
         float2 uv_MainTex;
     };
 
     void surf(Input IN, inout SurfaceOutput o) {
         fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color * 3;
         o.Albedo = c.rgb;
         //    o.Alpha = c.a;
 
         if ((c.g <= 0.65f && c.b >= 0.45f && c.r <= 0.65f && _AlphaValue == 0.0) || (c.g >= 0.6f && c.r <= 0.68f && c.b <= 0.68f && _AlphaValue == 0.0)) //Blue Rejection - Green Rejection
         {
             o.Alpha = 0.0;
         }
         else
         {
             o.Alpha = c.a;
         }
         }
         ENDCG
     }
 
             Fallback "VertexLit"
 
 }

Can anybody help me with this?

Thanx..