An ambitious approach to restoration, especially of works on paper supports, can be very counterproductive.
In the case of Bedřich Hawránek’s fine watercolor, which has of course accumulated damage in its existence in the form of yellowed paper from photo-oxidation, glue on cardboard, minor foxing-microbial stains and altered older retouching in the centre of the painting, the healthiest thing a restorer can do is to hold back.
A major intervention would have to involve treatment with the presence of moisture, which the technique in question does not allow. It is entirely appropriate to let go of perfection and perform minimal treatment. Minor retouching and choosing to remount with archival quality glass allows for maximum exclusion of the UV component of light degradation of the paper.
Any attempt to improve the artwork could negatively affect the appearance of the original in pencil and watercolor, an exemplary work by Hawránek of landscape painting of the second half of the 19th century.