Amount of Silver Nitrate Used Per Plate - Wet Plate Collodion

Quantifying Silver Nitrate Consumption in Wet Plate Collodion

Silver nitrate is one of the most significant ongoing material costs in wet plate collodion, yet it’s rarely quantified on a per-plate basis. I wanted to get a clearer picture of how much silver nitrate is actually consumed each time a plate is sensitized, and how that scales with plate size.

To do this, I prepared a small silver nitrate bath and measured its initial silver concentration using a volumetric titration. An acidified sample of the silver bath was titrated with a normalized potassium thiocyanate solution, using ferric ammonium sulfate as the indicator. This method provides a reliable measurement of dissolved silver nitrate and is well suited to tracking relatively small changes in concentration over time.

Once the initial concentration was established, I ran 23 coated plates through the bath using No. Z collodion. The plates were sensitized normally, with no attempt to conserve silver beyond standard working practice. After all plates were processed, I measured the remaining volume of the silver bath and performed a second titration to determine the final silver nitrate concentration.

By comparing the starting and ending concentrations—and accounting for the change in bath volume—I was able to calculate the amount of silver nitrate removed from the bath during use. Dividing that total by plate size yields an approximate silver nitrate consumption per plate.

Video of Process

Results

Based on this test, the average silver nitrate usage per plate was:

• 0.18 g of AgNO₃ per 4×5 plate

• 0.31 g of AgNO₃ per 5×7 plate

• 0.72 g of AgNO₃ per 8×10 plate

As expected, silver consumption increases with plate area. 

Why This Matters

Understanding silver nitrate consumption per plate can help with more accurate cost estimation, bath maintenance planning, and silver minimization strategies. 

This test represents a single working setup—different collodions, bath strengths, temperatures, or handling methods will certainly produce different results. Still, these numbers offer a practical reference point for anyone looking to better understand where their silver nitrate is going during normal wet plate work.

If nothing else, this exercise reinforces what most wet plate photographers already know intuitively: silver nitrate doesn’t disappear—it just ends up on your hands.