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Chemical Sources
USA:
UV Photographics (Raw and pre-mixed collodions, ÜSB Shellac and Sandarac Varnish, and more)
Bostick & Sullivan
Artcraft Chemicals (especially for silver nitrate)
For cheap Iron Sulfate: Kelp4Less on eBay or Bonide on Amazon
Graphic Chemical and Ink (asphaltum)
Rockland Colloid
UK and Europe:
Photo 42 (XXCL and MAD 83-11 shellac varnishes; silver nitrate)
Wetplate Supplies (Kevin Lunham, UK-based)
Silverprint
STE-UK
Rose Chemical
John Brewer Manchester (John@johnbrewerphotography.com)
Old Lab Tech
Western Photo
Restauro Online
Disactis
Mamut Photo
P.C.M.
Kremer-Pigmente (sandarac, shellac, asphaltum)
Australia:
Science Essentials
Labco (Brisbane)
Rowe
Gold Street Studios
Chemical Tips
Silver Bath Maintenance (Alex Timmermans)
Testing Ether for Peroxides (Frances Fullerton)