What color does the photo printed by the ancient method show after being fully washed?

1. Sir John Herschel found that many iron compounds can be sensitive to light in 184 1-1842.

Second, the blue sun method found that many iron compounds can be sensitive to light. Blue sun drying is the most widely used method in many iron salt prints derived from this discovery.

Third, the blue printing method is also called the iron cyanate (iron blue) printing method, and the most commonly used name is the blueprint printing method.

Fourth, it is often widely welcomed by people, because its chemical composition and treatment methods are very simple, and it has many uses. This basic printing method can generate a white image with blue midtones and shadow parts.

Five, you can use negative or transparent positive to make photos on paper or cloth washed with starch, or other materials.