1. A method for processing a document, the method comprising: selecting common and variant content from the document wherein the variant content includes content for a plurality of variants; automatically converting the common and variant content into a layered version document; checking whether some variant content violates one or more conditions; automatically modifying the some variant content in response to the condition(s) being violated; wherein the condition further comprises a condition that could cause a rendering of the document to violate an undesirable appearance condition; wherein the condition comprises painting a color intended only for common content; and wherein automatically modifying the some variant content comprises associating the some variant content with an error layer of the layered version document.