How to convince a designer the font is too light

Question

I'm not a designer. I dabble, but I have no formal training.
My background is User Experience and User Interface.
A designer has created templates to be used for PDFs. The font is not only light, but the designer has chosen to use a color value that is significantly towards the center of the black/white gradient.
As a result, when I try to read the PDFs that are produced, I have difficulty. I've asked around to other users in my company and they have also complained about the light, gray font.
Unfortunately, the designer is backed up by the brand manager, who claims that the font and color value represents our brand.
If our brand is all about being difficult to use, I would agree, but I need to make the argument that having a document users can read is more important than reflecting a brand.
I'm hoping someone can point me in the direction of some articles or discussions of this issue.

Answer 1

Plenty of folks have discussed this:
Me in article:
http://blog.webink.com/typography-from-points-to-pixels/
Me in video:
http://www.socialstudiesconference.org/node/238
"The Contrast Rebellion," an entire web site devoted to this issue:
http://contrastrebellion.com/
Web usability guru Jakob Nielsen writes:
Use colors with high contrast between the text and the background. Optimal legibility requires black text on white background (so-called positive text). White text on a black background (negative text) is almost as good. Although the contrast ratio is the same as for positive text, the inverted color scheme throws people off a little and slows their reading slightly. Legibility suffers much more for color schemes that make the text any lighter than pure black, especially if the background is made any darker than pure white (Nielsen 2000, p 125).
http://web.mst.edu/~rhall/web_design/color_readability.html
"regardless of the specific color combination, higher levels of contrast appear to lead to better readability (Bruce and Foster 1982; Radl 1980)."