A list of the skills for brushing pictures in the SS Source Shichen action of "Arknights Tomorrow" . Recently, many players don't know how to brush pictures. I hope everyone can refer to the content compiled by the editor.
Let’s talk about the specific material drops first.
OD-6: Soil 83.6% + Device 66.8%
OD-7: Light manganese ore 66.75%
OD-8: Grinding stone 57.7%
If you look at it purely from the perspective of the probability of dropping, it feels that they are all the same. In fact, the physical difference is not that big, and it is the same no matter which one you brush. However, this time it is special because the 6th picture is a drop of dual materials, and The material level is not that high, so I usually choose the last two materials to grind. But no matter what you brush, the drops will definitely be higher than the main line.
Generally, the last two materials are used. Whether they are purple chips or floor tiles, the priorities of these two materials are almost the same. The gaps are quite large. There is no big difference between them, so I personally recommend two. Brush as much material as you need, or balance the quantity according to the amount of materials you have.

In summary, you should make free choices based on your own material gaps. Look at your inventory, and if you are short of it, you can get more of it. You don’t have to worry about the probability of dropping it. If you have more of it, you will naturally go for that one. The probability has been stabilized and balanced. Another thing to mention is that OD-8 is very unstable due to the level mechanism. If you find it troublesome and cannot stabilize the idle process, I suggest you go for OD-7 without thinking.