I don't really get how the horizon effect is something that could be confused/conflated with the effect of dazzle camouflage. The horizon effect is described as a predictable bias in angle estimation, relative to the true angle, when a ship is viewed such that it's near the horizon. This presumably always applies to the view from a periscope, so it would be ever present in any remotely reasonable test of dazzle camouflage (whether to a neutral control or to conventional camouflage patterns). They just say that Blodgett’s control was "too vague to be useful", but it would have to be a truly <i>terrible</i> control to lead to the suggested confusion, e.g., comparing dazzle camouflage through a periscope to conventional camouflage viewed from above.