What is astoundingly clear after duplicating some imagery from our model the Gospel Book of Durrow is that this is a time consuming and hard process.
The Celtic knot work and interlace that occurs in the images was far too complicated to accurately replicate. This implies that the monks had training in how to create these very intricate forms. They understood how to look at their line work and make sense of the ways the lines move under over and around each other in a continuous form. This is just an observation, after staring at the interlace designs for several hours, but they seem, somehow reminiscent of plant forms that would occur in nature. Perhaps suggesting that the insular artwork present in the Gospel Book of Durrow is based on a long and complicated tradition of replicating these forms because of their significance to earlier medieval people.
However, I digress, the drying times for the pigments mixed with the egg yolk or the egg white binder was10 minutes. However, the India ink can take longer, 20 minutes to fully dry. The egg yolk binder paints acted like our modern acrylic paints and formed a thick glossy, colourful layer on the page. Though, you still have to be careful because the addition of this paint can make the India ink smudge, even after three hours of drying time. Two layers of this paint had to be added to get an equal coat.
In contrast, the egg white binder paint performed more like our modern watercolor paints. This meant that even after three coats of the paint the colours were not as brilliant or saturated as those mixed with the egg yolk binder. This paint also had a more severe reaction with the India ink, which would cause it to smudge on a much greater level even after drying for the same three hours.
While the paint mixtures sit the pigments will settle to the bottom and have to be continuously mixed back into the water and binder. It is also very hard to measure out equal parts of pigments, water and binder to mix together to make consistent paints!