Black spots on wet plate collodion

@Donald Qualls ... this is a jump from an old thread, and a question not related at all to pinhole cameras, but I just joined here and they won't let me DM you. So, aplologies for jumping in with a random question. Did you ever figure out the spots on your wet plates a few years back? I have spent the day with those same dark spots on tintypes (after sunning silver, using fresh silver, changing developers...) Your post is the only trouble-shooting reference close to what I am experiencing. Any thoughts are appreciated. Thanks!

Moderator edit: an image was included in this post taken from another thread by @D_Quinn : https://www.photrio.com/forum/threads/help-identifying-marks-wet-plate-collodion-photography.196495/
Please note this image is not original work by @J_Pendygraft

Welcome to Photrio @J_Pendygraft I have split off your post into a new thread; it appeared originally as a response in this thread which it doesn't relate to other than that @Donald Qualls also participated in it: https://www.photrio.com/forum/threads/can-i-make-a-pin-hole-camara-out-of-a-hasselblad-500cm.212151/

There are several people with wet plate experience on this forum; I'll alert in particular @retina_restoration.

Spots as you show usually relate to the following causes:
* Dust etc. due to improperly cleaned plates
* Debris floating in the silver bath that adheres to the plate; periodically sunning and filtering the silver bath tends to help with this.
* Undissolved particulate matter in the collodion mix itself
You mention sunning your silver bath; did you filter it as well?

J_Pendygraft said:

@Donald Qualls ... this is a jump from an old thread, and a question not related at all to pinhole cameras, but I just joined here and they won't let me DM you. So, aplologies for jumping in with a random question. Did you ever figure out the spots on your wet plates a few years back? I have spent the day with those same dark spots on tintypes (after sunning silver, using fresh silver, changing developers...) Your post is the only trouble-shooting reference close to what I am experiencing. Any thoughts are appreciated. Thanks!

Moderator edit: an image was included in this post taken from another thread by @D_Quinn : https://www.photrio.com/forum/threads/help-identifying-marks-wet-plate-collodion-photography.196495/
Please note this image is not original work by @J_Pendygraft

View attachment 399661

Click to expand...

I've never worked wet plate (though I have interest in it, I currently lack the resources to pursue it). I think you're confused who you're replying to.