Leaf vein length per unit leaf area (VLA; also known as vein density) is an important determinant of water and sugar transport, photosynthetic function, and biomechanical support. A range of software methods are in use to visualize and measure vein systems in cleared leaf images; typically, users locate veins by digital tracing, but recent articles introduced software by which users can locate veins using thresholding (i.e. based on the contrasting of veins in the image). Based on the use of this method, a recent study argued against the existence of a fixed VLA value for a given leaf, proposing instead that VLA increases with the magnification of the image due to intrinsic properties of the vein system, and recommended that future measurements use a common, low image magnification for measurements. We tested these claims with new measurements using the software LEAFGUI in comparison with digital tracing using ImageJ software. We found that the apparent increase of VLA with magnification was an artifact of (1) using low-quality and low-magnification images and (2) errors in the algorithms of LEAFGUI. Given the use of images of sufficient magnification and quality, and analysis with error-free software, the VLA can be measured precisely and accurately. These findings point to important principles for improving the quantity and quality of important information gathered from leaf vein systems.The leaf vein system delivers water, nutrients, and signals throughout the leaf, and sugars and signal molecules back to the rest of the plant, and supports the lamina mechanically (Roth-Nebelsick et al., 2001; Sack and Scoffoni, 2013). The leaf vein length per unit leaf area (VLA; also known as venation density) has key implications for leaf development, physiology, and ecology. In typical angiosperm leaves, the venation system is constructed of three orders of major veins (i.e., one or more first-order [1°] veins entering the lamina from the petiole, second-order [2°] veins branching off along the 1°vein length, and third-order veins forming a mesh in between) along with one to several additional orders of smaller, minor veins that complete the mesh throughout the leaf, typically bounding loops known as areoles (Ellis et al., 2009). The total VLA including both systems is positively related to physiological performance (e.g. hydraulic conductance and photosynthetic rate per leaf area; for review, see Brodribb et al