Tom Thomson's Rocky Shore and Sky Summer 1915

Harris and MacDonald planned to sort through Tom's art from the Shack, make comments on the back and distribute what they felt were the best examples of his genius.  This painting is another from that tall pile and displays the distinctive "TT Estate Stamp" on the bottom, front left corner. Some of the paint has since flaked off the wooden panel. Sad, but the story behind this painting is still intact.

Rocky Shore and Sky Summer 1915
Oil on composite wood-pulp board 8 1/2 x 10 7/16 in.
(21.6 x 26.5 cm)
Tom's paint box size. 

Location is the starting point for most Creative Scene Investigations. It certainly helped knowing that Tom did not travel far in the spring of 1915. Most of his painting locations were not far from Mowat Lodge and three square meals a day. The pile of rock in the front left of the painting would be recognizable today if the forest had not grown back to the shoreline. I do not recall seeing that particular knob of Canadian Shield on my paddles but it is certain to still be there. No worries though, the profile of Hayhurst Point and the eastern shore of Canoe Lake are sufficient to brand the vista. 

The weather and the colours were what really attracted Thomson to record this scene. With the easterly viewing angle established, the weather makes sense. The sky was full of large and developing cumulus with a few bands of higher altostratus. It takes time for such cumulus to be generated, so this weather situation was midday at the earliest. The morning would have been sunny and effective at heating up the ground, passing that energy into the hot air balloons that would become the cumulus clouds. The cloud faces were well-illuminated from the south. 

The southerly low-level winds shaping the vigorous cumulus clouds also indicate warm air being advected over Canoe Lake. Tom was likely located within the warm sector of the weather pattern but well to the east of the main band of weather preceding the cold front. 

The stable altostratus bands with cloudy gravity wave crests and clear areas in between as the troughs suggest a thin layer of moisture in an elevated stable layer. These swells would parallel the deformation zone. The location of these characteristic clouds must be the anticyclonic companion of the warm conveyor belt. Note that swells in the cyclonic companion are typically hidden within the thicker layers of moisture found in that rising area of the warm conveyor belt. 

The following graphic summarizes and explains Tom's location within the Conveyor Belt Conceptual Model. The deformation zone and multiple, parallel altostratus swells confirm the anticyclonic companion of the warm conveyor belt as the probable location for Tom's weather observation.

 It would have been a most pleasant plein air experience. I also suspect that there were no biting bugs and that this painting was a late spring experience before Tom turned his attention to fishing. 

Thomson was faithful to the exact shapes of the terrain and the clouds as described above. He did not labour the brush strokes in making those observations while still ensuring that they were accurate. However, it was the iridescence which probably caught his eye. The iridescence is the pastel colours viewed from the edges of the clouds. 

The sun is within perhaps 10 degrees of the iridescent clouds in  
the photo of the diffraction. Tom did not include the sun in his  
painting but it had to be above and to the right of his panel. 

Iridescence is the result of diffraction – a phenomenon that occurs when small water droplets or small ice crystals scatter the sun's light. This common phenomenon is most often observed in mid and high altocumulus or cirrus clouds. The pastel colours are very vivid and haphazardly arranged. Very uniform, small water droplets or small ice crystals individually scattering light through diffraction produce the strongest iridescence.  Larger ice crystals do not produce iridescence. Diffraction was explained in great detail in "Tom Thomson's Moonlight". 

The colours are brighter and more intense if the light source is within 10 degrees of the sun but can extend up to 40 degrees.

The iridescent cumulus clouds with uniform, very small cloud particles on their outer edges confirm that the cumulus clouds were young and vigorously developing while Tom painted. Larger cloud particles are characteristic of older and less robust clouds. This fact allows us to further conclude that the cumulus clouds were just starting to grow as a result of daytime heating. The sun was also within 40 degrees of the central portion of the sketch. These constraints require Tom to be looking toward the sun before solar noon. Tom did not include the sun in his weather observation but it must have been just above and to the right of his field of view.

Inscription recto: 

• l.l., estate stamp Inscription verso: 
• u.c., in graphite, Red Filter; 
• u.r., in graphite, NG National Gallery of Canada, Ottawa (1536) 

Provenance: 

• Estate of the artist 
• National Gallery of Canada, Ottawa (1536). Purchased 1918

There is so much science and nature yet to be discovered in the art of Tom Thomson. Thank you for reading and perhaps together we might preserve the wild places that remain. Tom would have liked that!

Warmest regards and keep your paddle in the water,

Phil Chadwick

PS: Tom Thomson Was A Weatherman - Summary As of Now contains all of the entries to date. 

PSS: Should you wish to have Creative Scene Investigation applied to one of Thomson's works that I have not yet included in this Blog, please let me know. It may already be completed but not yet posted. In any event, I will move your request to the top of the list. If you made it this far, thanks for reading!