Here are the original images from CR.

[Nov 2010] There seems to be some confusion in CR over which is which: in the main catalogue listing they are in the order here with B118 shown in full and the bottom of B119 obscured by a handrail. When describing the installation photograph shown below, this is reversed, with B109, B116 and B119 on the 'upper row'; B117 and B118 below, specifically B118 'lower right'. This is significant because I have based the reconstruction so far on the installation version, making the picture top right B119, i.e. the one with the 'Large Red Plane'. Having completed my first draft colour reconstruction of B119 on that basis, I'll stick with that for now.

Paintshop Pro [my pre-Mac days] includes a tool to correct perspectives which gives these results.

This gives a reasonable idea of the layout, though CR does not suggest size. I suppose that if I could obtain a copy of the 1924 Bulletin, depending on the images available, it might be possible to compare the Mondrians with other pictures on show for which sizes are known. There is a copy on sale for $125 at Fatbaba [dead link], but I'll have to try libraries. 

Back to colour identification in a while. Here's progress from Mondrian in New York which has the original picture of the 'Maîtres du Cubisme' exhibition at L'Effort Moderne, Paris. That's clearly the source of the image above because of the handrail obscuring the bottom of B119.

Applying perspective correction to the wall of Mondrians results in the first image. There are five on show, identified in CR as shown in the seond image.

B108 is the picture owned until recently by Yves Saint Laurent.

B116 was in the Stephen Mazoh gallery when the CR was written.

B117 is at the Dallas Museum of Art.

B116 probably offers the most useful reference for guessing the size and colouration of the lost paintings.

The titles provide the starting point: B118 Composition with Large Yellow Plane, and B119 Composition with Large Red Plane.

Size
B116 is 88.5 x 72.5 cm. This hadn't occurred to me until I compared the two versions of B116, but as the photograph was not taken with the camera perpendiclar to the wall, the photograph needs a further adjustment to match that ratio in the image of B116. After puzzling some time with the aid of a calculator, I arrived at this version of the wall.

Note that the light strip on the right side of all the pictures is the edge of the canvas. This should be ignored for the size calulations and, of course, for the colours.

Starting with B119 (Red), this comes out at an estimated 76x65cm

B118 (yellow) is tricker as it is not possible to tell how much of the picture is hidden behind the handrail. The width comes out as 53cm and assuming (fairly arbitrarily) that the proportions of the canvas were similar to B116 (1.22) and B119 (1.17), the height will be around 63cm.

Here's my first attempt at B119.

I'm a bit stuck on the colours to apply and so will concentrate my efforts elsewhere and return to these later. [Nov 2010] After some vacillation on the colours, this is my first draft of B119. I then checked the Catalogue and realised that, as described above, there is some confusion over which is B118 (Large Yellow) and B119 (Large Red). No matter, I'll stick with this rendering for now.

[Feb 2011] And here's a first draft for B118. I'm looking out for a compatible handrail to photograph and paste in. I am rather happier with B118 than B119.