The following points are listed here as an introduction to the form chosen for the Brief Reports and to the standards applied.
The dossiers for each of the paintings are in principle identically structured. An identification of the object (artist, title, date, signature, technique/medium, dimensions, inventory number) and an illustration thereof including frame, is followed by a summary, which presents all the important information and points of note regarding the painting in a concise form. This text is shown in the right-hand column when a work is selected. All the following details are listed in keywords in order to facilitate an overview and allow comparability.
An exception to the above principle is made for information on the picture support, where the keywords follow different criteria in order to represent the necessary distinctions between wood and canvas picture-supports. In principle we are concerned with the type, size, construction and texture of the support, and with canvas supports, also how it was stretched. For all wood panels the results of a wood-identification process are given (»Methods and Goals). Picture supports of board are always designated as artists' board when company trademarks or similar characterize them unmistakably as painters' requisites. In the English translation, all textile supports are referred to as "canvas", since, unlike the corresponding word "Leinwand" in German, which was specifically avoided, there is no suggestion that "canvas" might imply "linen". Details of standard sizes, manufacturers' marks and dealers' marks point to the fact that the product in question was commercially available. Manufacturers' and dealers' marks are additionally listed in an overview.
Details of the ground relate particularly to whether the artist used pre-primed material or primed the support him/herself, subjected it to additional treatment or modified it. A clear distinction is made in principle only between grounds that were applied before and after a canvas was stretched. Further distinctions have been avoided, as unambiguous assignment as commercial product or artist's own production is often impossible. Details of the binding medium of the ground are largely based on optical assessment. If analytical evidence is adduced, this is noted explicitly.
In the section composition planning/ underdrawing/ underpainting artistically and technically conditioned underdrawings are registered and described, insofar as they could be made visible by the use of intra-red reflectography (»Methods and Goals) . To prove and describe this phase of work, stereo-microscopy can however be used in individual cases, should a loose painting technique allow these underlying traces of the artistic creative process to be seen in visible light. The extraordinarily extensive evidence of painting planning in the Impressionist and Postimpressionist paintings examined in the course of the project is thus documented in the pictorial section of each examination report not just by infra-red reflectograms, but also by macroscopic and microscopic photographs, as well as photographs made with transmitted light and in the ultraviolet region.
Details of the paint-layer are based on intensive macroscopic and microscopic observations of the paint. The characteristic working method of the artist, the manner in which the paint was applied (e.g. wet-in-wet), the way the paint-layer was built up (including any revisions by the artist him/herself), the character of the brushstrokes or other utensils, together with the palette, are the specific features to the recognition of which examinations in transmitted light or with X-rays made important additional contributions. Statements relating to the palette begin with visual descriptions of the various colour tones on the basis of stereo-microscopy. A conscious decision was taken not to use "colour names" based on purely visual comparisons with contemporary pigments. The VIS-spectrometry technique (»VIS-spectrometry article by Dr Oltrogge) allowed numerous colorants (pigments and lakes) to be identified. The colorants thus identified are listed, with question-marks where the measurements did not permit unambiguous identification.
The entry on surface finish includes details on coatings applied subsequent to the paint-layer, and is not necessarily confined to the natural-resin solutions generally known as varnishes, hence the avoidance of this term in the section heading. In view of the fact that today the majority of Impressionist paintings have some kind of surface finish or varnish layer, the question of the authenticity of such finishes, or the original state, as the case may be, is of importance. The condition of an extant surface finish is a second parameter, and includes not just the typical aging phenomena (e.g. yellowing, craquelure), but also the degree of gloss, clues to the existence of more than one layer, remains of older finishes since removed etc.
Particular importance was also attached to the observation and description of the signature. Important in this connexion was the identification of the point in time it was applied (e.g. in the artist's own hand wet-in-wet or only after drying of the paint layer) or proof of a serial, in other words stamped signature applied at some later date. The description and assessment of the signature is often supported, through microscopic photography, by a comparison with signatures on other works.
Examination and description of the (decorative) frame of the works formed part of the examination strategy, but is only dealt with in detail in the Brief Report if it is an authentic frame, which, in the case of the works examined in this project, is rarely the case.
Finally there is a description of the work's state of preservation. Realizing that restoration measures and revisions could distort the interpretation, we have listed the observed changes and signs of aging of the works in brief.
Important literature, for example catalogues raisonnés, publications on painting technique and in certain cases correspondence from which quotations or comparative illustrations have been taken, is listed in a bibliography to each work.
The concise texts are supplemented by up to twelve selected illustrations which were made by high-resolution digital photography in the course of the examinations. These are not typical catalogue photographs, but rather photographs to accompany the searching eye of the conservator and art-technologist. At this point we shall briefly go into the standards applied. In addition to a photograph of the work as such in its frame, the primary purpose of which is identification, the sequence of illustrations begins with pictures of the work recto and verso without its frame (but of course with its stretcher, in the case of works on canvas). The edges are deliberately visible, often containing, as they do, important information. To illustrate the surface relief, an illustration under raking light, on principle from the left, follows. Raking-light indicators are only occasionally visible in the illustrations shown here, reference pictures with raking light indicators are additionally included in the picture's full dossier. These pictures are followed by others under ultraviolet, together with the IR reflectograms, and, where they made a contribution to the result, also transmitted-light photographs and X-rays. Detail photographs of the signature, characteristic features of the painting technique, marks and stamps, as well as illustrations relating to the state of preservation complete the pictorial section. All the details are accompanied by a scale "M", so that the size of the individual details can be verified. This scale is, depending on the motif, either 1 mm (microscopic photograph) or 3 cm.
For legal and copyright reasons, all the pictures can be reproduced only in limited resolution. For on-screen viewing, however, the high resolution can be completely exploited and with the use of the Zoomify tool, the viewer can see what the investigator saw, like for like.