Here’s a color palette based on your request for a typographic poster using Helvetica and Garamond with high to medium contrast.

json
{
  "palette_name": "Typographic Contrast",
  "colors": [
    {
      "name": "Deep Charcoal",
      "hex_code": "
          
          #333333
       "
    },
    {
      "name": "Soft White",
      "hex_code": "
          
          #FFFFFF
       "
    },
    {
      "name": "Rich Burgundy",
      "hex_code": "
          
          #9B1B30
       "
    }
  ]
}

Palette Description:

This palette features a deep charcoal for bold text, soft white for background clarity, and rich burgundy for accentuation, creating a striking contrast suitable for a typographic poster.

Do you have any specific themes or messages for the poster that you’d like to convey?