Перевод изображения в красный цвет, сохранив градации яркости

void __fastcall TForm1::Button2Click(TObject *Sender)
{
  Image2->Picture->Bitmap->PixelFormat = pf24bit;
  Image2->Picture->Bitmap->Width = Image1->Width;
  Image2->Picture->Bitmap->Height = Image1->Height;
  Image1->Perform(WM_PAINT, (WPARAM)Image2->Picture->Bitmap->Canvas->Handle, 0);
 
  for (int y = Image2->Picture->Bitmap->Height - 1; y >= 0; --y)
  {
    TRGBTriple* scanLine = (TRGBTriple*)Image2->Picture->Bitmap->ScanLine[y];
    for (int x = Image2->Picture->Bitmap->Width - 1;  x >= 0; --x)
    {
      const BYTE red =  0.322 * scanLine[x].rgbtRed +
                        0.550 * scanLine[x].rgbtGreen +
                        0.071 * scanLine[x].rgbtBlue;
      scanLine[x].rgbtGreen = red;
      scanLine[x].rgbtRed = red;
      scanLine[x].rgbtBlue = red;
    }
}}

 Graphics::TBitmap *img = new Graphics::TBitmap;
 img->Width  = Image1->ClientWidth;
 img->Height = Image1->ClientHeight;
 img->Canvas->CopyRect(TRect(0,0,img->Width,img->Height),Image1->Canvas,TRect(0,0,img->Width,img->Height));
 img->PixelFormat = pf24bit;
 TRGBTriple *rgb = NULL;
 for(int y = 0; y<img->Height; ++y)
 {
  rgb = (TRGBTriple*)img->ScanLine[y];
  for(int x = 0; x<img->Width; ++x)
  {
   rgb[x].rgbtRed = 255;
  }
 }
 Image1->Canvas->CopyRect(TRect(0,0,img->Width,img->Height),img->Canvas,TRect(0,0,img->Width,img->Height));
 delete img; img = NULL;
 
 
/*Либо так, тоже прикольный результат:
   вставить вместо "rgb[x].rgbtRed = 255;"
*/
      const BYTE red = 0.550 * rgb[x].rgbtGreen + 0.071 * rgb[x].rgbtBlue;
      rgb[x].rgbtGreen = red;
      rgb[x].rgbtBlue = red;