First I lightly sketched in the background and gave the horse a base coat. Since white is composed of many colours, a whole rainbow had to be laid down.

Next I did the same for the rest of the room, blocking in the underlying colours. The section in the middle was detailed a little.

I then refined the background. It looked very wrong until I roughly filled in the beams with brown. The background was still not complete, but close to.

Now, the completed image. I painted the details of the horse and had to make the horse substantially darker, while still having her appear white. The floor was darkened in some places, lightened in others. I refined the roof beams and then I was finished.

 I like the idea of putting a substantially detailed background into my work, as backgrounds are often neglected in painting.

My references for this image were as follows:

Horse

Background (Northwood asylum)