problems with photo engravings, some lines come out


Hello everyone, I’ve been laser engraving photos, but I’ve noticed that some dark lines came out, they didn’t come out before, I try some adjustments but they don’t go away, I lower the speed, but it doesn’t work, I have my DPI at 318, I’ll leave you Some photos so you can see what I’m talking about, thanks
hola a todos , e estado engrabando fotos en laser , pero e notado que salieron unas linieas oscuras, antes no salian , e escho unos ajustes pero no se quitan, e vajdo la velosidad ,pero no funsiona, mi DPI lo tengo a 318 les dejo unas foto para que ven de lo que hablo, gracias

Maybe check here for all mechanical adjustments you can try: Guide to mechanical adjustments and maintenance