Porta Aperta publishes practical, technical explanations of how trading cards, playing cards and custom cards are constructed. Our coverage connects caliper, core, opacity, stiffness, coating, lamination, printing, cutting and corner radius to the way a finished card feels, bends, shuffles, wears and looks.
Research and source selection
We match the source to the claim. For material and production specifications, we prefer paper and card manufacturers, coating and laminate suppliers, print and converting-equipment documentation, and professional printer specifications. Current product details, policies and other changing facts should come from current first-party sources where practical. Secondary and community sources can add context or identify practical issues, but estimates and user reports are not treated as manufacturer specifications.
Technical claims are considered in the context of the exact construction discussed. A GSM figure alone, for example, does not establish caliper, stiffness or finished-card behavior. When measurements are available, we identify units and relevant conditions. Environmental variables can matter, as explained in how humidity changes paper card thickness and feel. Calculations should be traceable rather than presented as unexplained results.
Evidence, illustrations and evaluation
We distinguish among researched explanation, generated illustration and documented firsthand evidence. Research-based conclusions draw on sources, specifications and technical reasoning. Generated diagrams, scenarios and sample calculations are explanatory aids, not observations or test results. Claims about purchases, equipment use, measurements or product testing require documented evidence.
We do not assume that every product discussed has been personally tested. Comparisons of commercial cards identify whether information comes from measured samples, manufacturer specifications or community estimates. Recommendations consider the variables relevant to the reader’s task. We state meaningful limitations or uncertainty when they could change the conclusion.
Attribution, opinion and commercial relationships
We attribute specifications, study findings and company claims when the source matters to understanding the statement. Editorial analysis and opinion are presented as judgment, with the supporting evidence or practical reasoning made clear. A relevant affiliate, sponsorship, ownership or other documented commercial relationship is disclosed on affected content. That relationship does not replace evidence or remove the need to explain tradeoffs.
Corrections and updates
We aim to correct material factual errors and update content when specifications, products or policies change. Readers can report a possible error by emailing contact@porta-aperta.org with the page address, the statement in question and any supporting source. We review the underlying evidence and revise the affected content when a correction is warranted.