I've looked at lots of images from the civil war period shot on Wetplate. Thousands of images as published in photo books of the civil war, as well as I have books of Matthew Brady and Alexander Gardner.
The coating of the collodion appears to be smooth and even.
Many, many modern wet-plate images appear to have coating defects, streaks, etc. Is this just an issue with technique? Or are the supplies different and not as easy to work now?
If any of you check Shorpy photo on the internet they run a civil war era image several times a week, in addition to later vintage images. Of course you can see dust spots, and sometimes cracks in the original glass plate, but the "coating" appears to be consistent and fairly even.
Just want opinions.