During this period, i.e. in the 15th century, mainly two types of mediums were used to execute the underdrawing – fluid and dry. The fluid medium, some type of ink or a black pigment mixed with oil-based binding agent, was applied to the surface with a brush or pen. The underdrawings in dry mediums were executed with charcoal, black chalk or metalpoint. Since the artists workshops of the era were also commercial enterprises, the creation of the works of art was carefully considered, and as a rule, in addition to the master (or masters) various helpers – journeymen, apprentices, and assistants – were involved in different roles. For this, mechanisms had to be employed to optimise the work process thereby enabling a larger circle of executors to carry out the master’s intent. For example, various methods were developed for transferring the small-scale or life-size (so-called cartoon) sketches onto the prepared surface. Templates were also used to execute repetitive elements and ornamentation.
On the Tallinn altar produced by the Rode workshop, the existence of a very dense and detail-rich underdrawing was established, which was used to compose the entire painting in detail. The structure of the underdrawing corresponds to the traditions of the 15th century: the contours of the details and main light-dark areas are outlined along with the shaded areas that are indicated with dense hatching strokes. In places, the fabric folds are marked with characteristic hook-shaped terminations, which are, however, only visible on some of the figures. The drawings seem to have been executed with a fluid medium characteristic of 15th-century traditions, using either a brush or pen. Although the use of dry medium that allowed for greater spontaneity gained popularity in the second half of the 15th century, Rode seems to have remained true to tradition.
Two stages are observable in the execution of the underdrawing. Firstly, the main elements of the composition were drawn on the ground with relatively fine (brush) lines, and the light-dark areas marked with rapid uneven hatching. Thereafter, the main accents (although mostly for the fabric folds) were emphasised using a fluid medium of a somewhat different consistency (which appears darker under the infrared light) by using considerably more impetuous and wider lines.
In some places, the underdrawing seems to be sketchier and more spontaneous, and in others, it seems to carefully follow a given scheme. The usual practice of the artists’ workshops at that time was to use sketches by the master-artist that the assistants transferred to the prepared surface. It is quite natural to assume that in order to produce such a huge commission that needed to be completed rapidly (in 3 years), Rode needed a larger than usual team of assistants and well-thought solutions to realise his vision. However, no clear signs have been found that would indicate the specific method used to transfer the preparatory drawing.
If in the case of the draperies, fabrics and various attributes/items, one could assume that a given diagram was followed, then in the case of the figures, faces, and feet, the drawing is considerably sketchier, more intermittent, searching and constructed with a network of dense and spontaneous freehand lines. Often, slight changes in the placement of the hands and faces are noticeable, as are corrections in the outlines, and a searching for the right position.
Several compositional changes have also been made during the painting process and an entire series of initially planned details have been left out.
If the underdrawing of the Tallinn retable is carefully composed, filled with details and many smaller and larger compositional changes, in a sense, the underdrawing of the Lübeck altar is its opposite. The figures are indicated only with a few exact lines and hatching and they correspond almost completely to what appears on the painting layer. A slightly sketchier, but again a laconically executed, freehand underdrawing is visible on the outer wings and predella. At the same time, the character of the drawing and the nature of lines fully correspond to the St. Nicholas retable and, based on the extremely similar nature of the paint layer, confirm its attribution to the same master.
If the St Nicolas retable has a very dense and detail-rich underdrawing filled with details and many smaller and larger compositional changes, in a sense, the underdrawing of the St Lukas retable is its opposite. The figures are indicated only with a few exact lines and hatching and they correspond almost completely to what appears on the painting layer. A slightly sketchier, but again a laconically executed, freehand underdrawing is visible on the outer wings and predella, which has very similar style to the one on St Nicolas altar.
How does one explain the great differences in the relative importance of the underdrawings of the Tallinn and Lübeck retables? One could speculate that this can be connected to the story of how the paintings were commissioned and executed. Realizing the retable for Lübeck was apparently one of the most significant commissions for Hermen Rode, since it was to be installed in St. Catherine’s Church in his hometown, on the altar of the Guild of St. Luke, the most important organisation for artists and glaziers. The importance of the commission is confirmed by that fact that the master apparently painted his own portrait on the retable along with his signature – Hermen Rode – on the figure’s collar. Considering the importance of the commission, one can assume that the artist made a greater than usual contribution to the execution of the retable himself and made less use of his helpers. This means that, as such an experienced and capable master, he had no need for such a thorough preliminary composition.
On the other hand, the St. Nicholas’ retable was a commission from Tallinn, a faraway Hanseatic town. It was also huge in size and the completion deadline was relatively short. From the documents we know that the commission for the retable was dispatched to Lübeck in 1478 and the completed work arrived here in 1481, i.e. a maximum of three years was spent on the execution. Considering the volume of the work – from the acquisition of the materials and construction of the frame to the carving of the all the extremely fine details – the painting process had to proceed quite rapidly. The master probably involved a considerably larger team than the few assistants that could usually be found in an artist workshop at that time. In order to carry out the master’s plan, a thoroughly prepared composition was required in the form of a sketch and underdrawing. Can we assume that more hands were involved already during the transfer of the underdrawing than just the master himself (examining the nature of the fabric folds, one can assume that some mechanical transfer method was used), but when it comes to the faces, hands and other more complicated parts the master’s own inquisitive freehand line is visible? Although it is almost impossible to identify different handwritings in the painting layer, it is quite likely that it was executed by a larger group of assistants. The very detailed underdrawing created the precondition for this.
This may also be the reason why many tiny details were left out in the final painted composition, for which no clear ideological reasons seems to exist. Was the delivery deadline for the altar approaching quickly, the work had to be dispatched to Tallinn and therefore some of the planned details had to be eliminated?