| 1/00 | Etching metallic material by chemical means |
| 1/02 | Etching metallic material by chemical means Local etching |
| 1/04 | Etching metallic material by chemical means Local etching Chemical milling |
| 1/06 | Etching metallic material by chemical means Sharpening files |
| 1/08 | Etching metallic material by chemical means Apparatus, e.g. for photomechanical printing surfaces |
| 1/10 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) |
| 1/12 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Gaseous compositions |
| 1/14 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions |
| 1/16 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions Acidic compositions (C23F 1/42 takes precedence) |
| 1/18 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions Acidic compositions (C23F 1/42 takes precedence) for etching copper or alloys thereof |
| 1/20 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions Acidic compositions (C23F 1/42 takes precedence) for etching aluminium or alloys thereof |
| 1/22 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions Acidic compositions (C23F 1/42 takes precedence) for etching magnesium or alloys thereof |
| 1/24 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions Acidic compositions (C23F 1/42 takes precedence) for etching silicon or germanium |
| 1/26 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions Acidic compositions (C23F 1/42 takes precedence) for etching refractory metals |
| 1/28 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions Acidic compositions (C23F 1/42 takes precedence) for etching iron group metals |
| 1/30 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions Acidic compositions (C23F 1/42 takes precedence) for etching other metallic material |
| 1/32 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions Alkaline compositions (C23F 1/42 takes precedence) |
| 1/34 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions Alkaline compositions (C23F 1/42 takes precedence) for etching copper or alloys thereof |
| 1/36 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions Alkaline compositions (C23F 1/42 takes precedence) for etching aluminium or alloys thereof |
| 1/38 | Etching metallic material by chemical means Etching compositions (C23F 1/44 takes precedence) Aqueous compositions Alkaline compositions (C23F 1/42 takes precedence) for etching refractory metals |