I’m just a hobbyist and these are my experiences…
Using pencils for weathering isn’t new, but it’s new to me. I tried a few of AK Interactive’s Weathering Pencils recently. I wanted to see how to best use them in a freight car build. In most modeling articles I have read they are applied near the end or at the end of the weathering process.
But when I tried them this way, they left a sheen; after all they are just grease pencils. This did not appeal to me, so I tried something else…
I made up some samples from Evergreen freight car siding (1″ x 2″ size), painting them in my standard AK mixture for red brown (https://1935to1945homodeller.wordpress.com/2022/10/29/period-freight-car-colors/).
The method that I like best, for now, is to apply these pencils in the “pre-weathering” stage, before glossing for decals. I find that the gloss varnish better preserves the appearance of the pencil application. The final flat varnish will eliminate the greasy look that I do not care for.
After the gloss varnish, I applied a black oil wash and then some Tamiya TS-80 Flat Clear lacquer spray.
As expected, the black oil wash muted the tones some, and I like the effect. A thinner oil mixture would show more of the pencil application. I think I will be using these pencils mostly on wood sheathed cars.