MEASURING THE THICKNESS OF THE SILVER LAYER WHEN ELECTROPLATING PLATES FOR DAGUERREOTYPE
When electroplating silver onto copper or other metals for use in the daguerreotype process, it is valuable to know how to determine the thickness of the resulting silver layer deposited onto the plate. This can be critical in determining if you’ve achieved adequate silver thickness to allow for proper surfacing and polishing of the daguerreotype plate, and will help you determine how resilient the plate will be to repeated wiping and reuse.
PLATING THICKNESS CALCULATOR
Theres is a bit of math involved in determining the thickness of the deposited silver but it’s all quite manageable. I’ve created the calculator on this page to make it easy for you if you’d just like to punch in your numbers and get your results. Sometimes it can be useful to understand exactly what the calculator is doing for you. The information presented on this page explains all of the math and demonstrates how to find these results yourself using only a few simple formulas. Understanding the math will allow you to find your own results without dependence on any tool other than your brain. Understanding the math will also be valuable if you want to change any of the variables here or if you’re using different units of measurement than are provided here and which the calculator is programed to use.
How to Calculate the Thickness of the Silver Layer
To calculate the thickness of the silver layer, you will need to know the following:
The area of the plate (L x W) in centimeters (cm)
The weight of the silver layer
The density of silver
CALCULATING THE AREA OF THE PLATE
To calculate the area of the plate, multiple its length in centimeters by the width in centimeters. If you have the length and width in inches, multiply both by a factor of 2.54 to convert each dimension into centimeters.
Example: If we are working with a 5”x7” plate, we first convert the dimensions to centimeters
5 * 2.54 = 12.7cm
7 * 2.54 = 17.78cm
Then multiply the length in cm by the width in cm to get the area.
12.7 * 17.78 = 225.806 square cm
CALCULATE THE VOLUME OF THE SILVER LAYER
For this, we need to know the density of pure silver. The density of silver is 10.49 g/cm³.
We also need to know the weight of the silver layer. The best way to do this is to weigh the plate immediately before electroplating and immediately after. We’re woking with very small weights here so you will need to use a laboratory grade scale capable of measuring at least down to the milligram (0.001g) but one capable of measuring to 0.1mg (0.0001g) is best.
Laboratory scales are expensive and can be difficult to find so if you do not have access to one, you can use the table provided here to get a close and usable estimate for our purposes. The table provides the weight of silver deposited relative to time at a specific amperage (0.2 Amps - this is generally the amperage you want to use for silver plating at home). Accuracy depends on constant amperage at 0.2 Amps among other things but this should at least give you a close idea if you are using that amperage and as long as you are able to maintain a relatively consistent amperage during your plating process.
To calculate the volume of the silver layer, divide the weight of the silver layer by the density of silver.
Example: For our 5x7 plate, if we’ve electroplated at 0.2 Amps for 10 minutes, our silver weight is 0.134g.
Weight / Density = 0.134 / 10.49 = 0.01277 cubic cm.
CALCULATE THE THICKNESS OF THE SILVER LAYER
To calculate the thickness of the silver layer, divide the volume of the silver that you arrived at in the previous step by the surface area of the plate that you determined in the first step.
Example: For the 5x7 plate with a silver volume of 0.01277 cubic cm and a surface area of 225.806 square cm
Volume / Density = 0.01277 / 225.806 = 0.000056cm
CONVERT RESULT TO MICRONS
To convert the result from centimeters into microns, multiple the result by 10,000.
Example: A plate with a silver thickness of 0.000056cm
0.000056 * 10,000 = 0.56 microns
So with the above example, a 5” x 7” plate that is electroplated at 0.2 Amps for 10 minutes, the resulting thickness of the silver layer will be 0.56 microns.