"The most accomplished engravers of the period were engaged to translate his original paintings into stipple engravings, in which the plates are etched with small dots rather than lines. Indeed, Redouté helped refine the stipple engraving process to best capture the subtle effects, luminosity, sheen and dimensionality of his original paintings. Through a method he invented in 1796, the colors were applied to the engraved plate a la poupée before each printing, “giving to our prints all the softness and brilliance of a watercolor,” as Redouté noted. Finally, each print was finished with additional coloring by hand. Redouté’s high standards are evident in the striking way in which the resulting prints capture the subtle delicacy of flower petals and foliage."
'Les Roses' was published in 3 volumes between 1817 and 1824 and the 170 illustrations depict flowers from the Malmaison estate* of Empress Josephine (mostly). The deluxe original editions were very limited in numbers and were financially unsuccessful. A later octavo version proved popular but only about 300 copies were ever printed. A single original print may fetch up to $18,000. Many of the original watercolour paintings by Redouté (which he sold to reduce debt) were lost in the fire at Tuileries Palace* in 1871.
A number of versions of 'Les Roses' are available online. I've opted to display images from NYPL which are probably manipulated with respect to light/colour balance. In the second to last image above you can see a comparison to the Library of Congress version which is available from the Rare Book Room, versus the same flower print from NYPL. The last image is also from the Rare Book Room which have a second version of 'Les Roses' from the Warnock Library. Quite a few commercial print galleries of course have varying quality (and numbers of) prints available.