Having found this article, I will assume that you've been on a quest to source scratch-dig comparison sets or paddles, only to discover that the options available are limited at best.
Whether you’re looking to find a better solution, or simply seeking to replace a worn, damaged or lost set, this article has been written to help.
In the next section we summarise all of the available (and discontinued) scratch-dig comparison products that are suitable for supporting visibility based optical surface quality assessment; providing you with key information on the options and where you can procure them.
Notes:
- The options listed are those intended for use when inspecting to the following standards: MIL-PRF-13830B, MIL-C-675C, ANSI/OEOSC OP1.002:2009 (Visibility), or ISO 10110-7 / ISO 14997 (Visibility).
- Red text indicates an inconsistency with the MIL-PRF-13830B standard.
| Available - RedLux - Comparison Reference Set (Cosmetic and Visibility) | |
| Cost estimate (per set) | TBA |
| Description | Single glass panel containing 5 scratches and 5 digs. |
| Imperfection type | Real glass surface imperfections. |
| Scratch grades | #10 #20 #40 #60 #80 |
| Dig grades | #5 #10 #20 #40 #50 |
| Availability/Source | RedLux |
| Available - ThorLabs (Micros Optics) - Scratch-Dig Panel | |
| Cost estimate (per set) | £400+ ($500+) |
| Description | Single glass panel containing 7 scratches and 8 digs. |
| Imperfection type | Photolithographically marked patterns. |
| Scratch grades | #5 #10 #20 #40 #60 #80 #120 |
| Dig grades | #5 #10 #20 #30 #40 #50 #70 #100 |
| Availability/Source | ThorLabs (Micros-Optics) |
| Available - ThorLabs - Optic Surface Imperfection Scratch-Dig Paddle | |
| Cost estimate (per set) | £120 ($150) |
| Description | Single plastic paddle containing 7 scratches and 7 digs. |
| Imperfection type | Moulded plastic surface imperfections. |
| Scratch grades | #10 #20 #40 #60 #80 #120 #160 |
| Dig grades | #5 #10 #20 #40 #50 #70 #100 |
| Availability/Source | ThorLabs |
| Discontinued - ThorLabs (Jenoptik) - SDPK - Scratch-Dig Paddle | |
| Cost estimate (per set) | £100+ ($125+) |
| Description | Single plastic paddle containing 7 scratches and 7 digs. |
| Imperfection type | Moulded plastic surface imperfections. |
| Scratch grades | #10 #20 #40 #60 #80 #120 #160 |
| Dig grades | #5 #10 #20 #40 #50 #70 #100 |
| Availability/Source | Discontinued |
| Discontinued - Edmund Optics - #53-197 - Scratch-Dig Paddle | |
| Cost estimate (per set) | £100+ ($125+) |
| Description | Single plastic paddle containing 7 scratches and 7 digs. |
| Imperfection type | Moulded plastic surface imperfections. |
| Scratch grades | #10 #20 #40 #60 #80 #120 #160 |
| Dig grades | #5 #10 #20 #40 #50 #70 #100 |
| Availability/Source | Discontinued |
| Discontinued - Davidson Optronics D668 Comparison Set | |
| Cost estimate (per set) | £4000+ ($5000+) |
| Description | 10 separate samples representing 5 scratches and 5 digs. |
| Imperfection type | Real glass surface imperfections. |
| Scratch grades | #10 #20 #40 #60 #80 |
| Dig grades | #5 #10 #20 #40 #50 |
| Availability/Source | Discontinued |
| Discontinued - Bryson Optical Corp - Comparison Standard | |
| Cost estimate (per set) | No data available. |
| Description | Single assembly containing 5 scratches and 5 digs. |
| Imperfection type | Real glass surface imperfections. |
| Scratch grades | #10 #20 #40 #60 #80 |
| Dig grades | #5 #10 #20 #40 #50 |
| Availability/Source | Discontinued |
If you are inspecting scratches and digs in accordance with MIL-PRF-13830B, MIL-C-675C, ANSI/OEOSC OP1.002:2009 (Visibility), or ISO 10110-7 / ISO 14997 (Visibility), then there are two sets currently available for consideration; RedLux's Comparison Reference Set and the plastic moulded Optic Surface Imperfection Scratch-Dig Paddle sold by ThorLabs.
Scratch-Dig Comparison Reference Set