My views on the term 'screen accurate'

The term 'screen accurate' has been used quite liberally when refering to props and prop replicas. Often differing definitions of the term lead to quite heated conflicts especially given the anal retentiveness of many prop collectors. To clear up any confusion, here are my views of the term and how they apply to my work.

First off, 'screen accurate' to me denotes that the replica must be externally, visually and dimensionally exact to the prop it is copying and where possible, built using either original found parts, parts copied from original found parts, or from parts custom built using materials visually identical to the original but to the same dims.

How accurate must these dimensions be? For me, it depends on the size of the prop. The smaller the prop, the more accurate the dimensional tolerances have to be. There is a perfectly sound logic behind this. A 0.7mm error on a dimension of, for instance 1mm, is a whopping 70% error based on overall size.  Whereas a 0.7mm error on for instance, K9 or a full sized Dalek is negligible as it would no doubt represent fractions of a percent error. Therefore it can safely be said that dimensional errors must be small, in practical terms. Single figure percentages at most but in this case, microns. These are the tolerances I feel work with my sonic screwdriver replica where visual aesthetics do not suffer. Any greater than that and you will find that the end result will look slightly 'off' even if you cannot pinpoint the exact reason.

Adding sound to something does not make it any less screen accurate as externally it does not suffer since the sound chip is essentially an 'invisible compromise' that adds value but does not detract from visual accuracy. In the same vein, stainless steel and aluminium can look visually identical but stainless steel is harder, heavier and has characteristics more suited to practical usage.