For more uniform materials from the former Gustave De Ridder (1861-1945) collection:

Go to the Gallica site 'Advanced search' page:

http://gallica.bnf.fr/advancedsearch?lang=EN

Change the first search field from 'title' to 'all'; then type 'De Ridder' in the space to the right; click on 'Start search'.

On the left, under the Green 'Type of document' click on 'image (79)'. Voila!

There are 79 separate volumes of plates available from this collection.

Enjoy.

Please Note: These instrucrions are for the English page - EN - but should work for other languages by substituting for the proper word in the other language.