Show Screenshot image on GUI, linear color space , Need help

I made a script to take screenshot and display the image on GUI. But since my project has to use linear color space, when I use the screenshot image as Texture2D on GUI, the image become dark. is there any solution for this problem?

     // to capture screenshot//
     Texture2D screenCap;
      screenCap = new Texture2D(1024,1024, TextureFormat.RGB24, false);
     screenCap.ReadPixels(new Rect(Screen.width /2 - 512, Screen.height /2 - 512 ,1024,1024), 0, 0);
     screenCap.Apply(); 
 
 // to see  captured image void OnGUI//
 GUI.DrawTexture(new Rect(100, 100, 300, 300), screenCap);