For students, hobbyists, or occasional conversions (≤20 drawings/month), is fully capable and free.
Be wary of "free" software that asks for your email before converting. Many of these are trojan horses for malware or subscription traps. Stick to open-source (Inkscape, QCAD, FreeCAD) or reputable online viewers only. scan2cad free alternative
She opened GIMP (free, open-source Photoshop). With Colors > Threshold , she turned the gray photo into stark black-and-white line art. She erased dust spots manually. Saved as a BMP. or occasional conversions (≤20 drawings/month)