100 sheets of stolen vellum

[Koen G]

Following Lisa's assessment of the parchment as basically scrap, I wonder why someone would even go through the process of making 100+ bad parchment sheets, which obviously was a lot of work. Why not use paper? I see several scenarios:

1) Lack. The VM was created in an environment where parchment / paper simply was not available. Secluded in a rural place or during a severe crisis, in exile, ...
As Lisa suggested, the author or a community may have produced all materials including ink and pigments DIY style. This is however hard to reconcile with the necessary reference imagery, unless the artist drew everything from memory. Which might explain some (but far from all) oddities. On the other hand, some imagery looks to have been copied relatively faithfully.

These are good questions to ask. Were there maybe places in the first half of the 15th century where paper wasn't all that common yet? Or harder to come by than low quality parchment? 

I can see the appeal of a "self-made" argument. The preparation and application of the pigments also displays low quality and skill, but still sufficient to get the job done. 

I don't think any supposed access to sources is a problem. Access doesn't mean ownership. And even if people, families or institutions owned a number of books, that doesn't mean that they still have the means, ability or desire to buy high-grade materials. It's possible for an individual or institution to have limited financial means, but also have a library: from past acquisitions, inheritance, donations...