This railroad work was in some way setting the course, being completion and new beginning at the same time, because it seems that with the activity for the enterprise PLM Baldus’ own interest in the commercial perspectives of photography grew even more. He also wants to be closer to his children after the death of his mother-in-law in 1862. For years Baldus had a small company in the Rue d'Assas, with a dozen of employees and assistants, had sold his works in half of Europe, but the rapid development of photography and reduction of production cost opens up new interesting opportunities. He makes series of photographs of Paris and produces stereoscopic images, the latter in large editions with rather ordinary print quality.

Already in 1855 he had developed his own method for photo-engraving. Baldus’ method was precise and flexible, allowing both low pressure and high pressure. He did not register for a patent for his invention and kept the details of his "heliogravure" process as trade secret. He continues to develop the process further, using chromium salt and a bath of ferric chloride.
This is the foundation of his new activity as a printer and publisher. In the late 1860s he publishes large format albums and prints of his photographs of architecture and ornaments of the Louvre and the Palais des Tuileries, just before these buildings are damaged and destroyed during the revolt of the Paris Commune. He also publishes collections of engravings of the work of Cerceau and in the 1870s the „Principaux Monuments de la France".