To locate when a defect arose, compare any surviving flat-print evidence with the finished canvas and record where the mark sits relative to folds, corners and the image. That distinction matters because the appropriate correction can be quite different. Start with the original approved image and any production-stage photographs or test pieces, then document the finished object without dismantling it. A visual clue can guide an investigation, but it should not be presented as proof of when or how the damage occurred.
Compare the printed image and any earlier production evidence
Establish which artwork file and proof were approved, and look for the alleged flaw in them. An apparent scratch may be a deliberate graphic element, a textured scan or a defect already captured in the source photograph. If a flat printed sample or a pre-stretch photograph exists, compare the same position with the finished canvas. Make sure the comparison accounts for crop, orientation and wrap, because a feature may move from the front onto a side during finishing.
If the source file is clean but a flaw is visible in a pre-stretch print, the printing or handling stage before assembly becomes a reasonable area to investigate. That still does not identify a precise cause such as ink contamination or a damaged nozzle. Ask the print professional for relevant production records, material details and any retained test strip. Do not infer the manufacturer's equipment or coating process from the canvas appearance alone.
A narrow diagonal streak appears near the lower-left corner after stretching. An earlier workshop photograph of the printed sheet shows the image before it was folded, but that image is low resolution and does not establish whether the streak was absent. Examine the original approved file, dated production photographs and the finished corner, noting where the streak crosses the edge. A repeated mark on the flat sheet suggests a different step from a new crease at the fold. Keep competing explanations open until actual production records are checked.
Study where the flaw sits on the finished support
Inspect the canvas in diffuse light, especially near corners, folds, edges and stretcher contacts. A crease concentrated at a wrapped corner may raise a different question from a repeated line extending across the full image. A surface mark near a staple line or outer frame may deserve investigation of assembly and handling. Record its position relative to the picture and physical edges. Do not pull fabric, remove staples or press on the back to reproduce the mark.
Consider whether the flaw tracks the geometry of stretching. Local tension changes or a fold can create patterns near the corners that are not visible in the central field. A defect across several unrelated image regions might point elsewhere, but only an object-specific examination can establish the distinction. Photograph the full front, sides and relevant close-ups with consistent scale and orientation. If the support itself is unstable, stop handling and seek qualified help.
Preserve evidence and agree on the next inspection
Create a short timeline with the approved file date, printing or proof date where known, finishing date and delivery date. Add photographs from each stage without editing away details. Describe what was observed and when, not what you assume happened. A trained printer may need to inspect the substrate and print record; an art conservator may be appropriate for a valuable or physically damaged object. Their roles are not interchangeable.
A practical report identifies the defect's shape, size, position and visual impact at normal viewing distance. Note whether any prior file or photograph shows the same feature. If the producer proposes re-stretching, cleaning or applying a coating, request an explanation of the risks and why that treatment is appropriate for the actual materials. Do not accept a home remedy simply because it appears quicker than a formal production review.
The strongest conclusion may still be that the stage of introduction is undetermined. That is preferable to inventing certainty. A documented comparison can narrow the possibilities and guide a sensible resolution, whether it involves image correction, production inspection or specialist intervention. What matters is preserving the artwork and the evidence while separating observable facts from hypotheses.