Redline

Lists every channel actually used on the page — CMYK process plates and spot colors alike, including CMYK content inside placed raster images. Uncheck a channel to knock it out of the artwork above (best-effort: paints its own paths white, so it can't reconstruct other ink genuinely overprinted beneath it). Click a channel's name to isolate and diff it directly against the same channel in the other file. Note: for vector content this is exact; for a CMYK image we can only detect its position/size, not its individual pixels, so it shows as a flat gray placeholder — real per-pixel photo content isn't compared at that level.