Thanks for all of the input regarding Black 12. The bottom color of this aircraft isn't clear and as I've said at the beginning, this is not intended to be a definitive build of the MiG-3. So without making any claims of accuracy or correctness, I am going with white above and below and see how that turns out.
First I have to finish the preshading and the front fuselage is masked off. Using the technique that I employed on my 109G-10 Erla build, I've added random preshading patterns over the entire aircraft to give the finish a bit of unevenness and depth. The effect is subjective to be sure and I view this in the same vein as some of the "oil filtering" techniques employed as postshading. To mix things up, I used green on the upper wings instead of black, mostly as a test bed.
Here is the starboard wing after multiple passes of highly thinned white. Although it is difficult to see, you can discern the effects of the preshading.
To illustrate how this effect is achieved, here is the port wing in different stages of painting. The white is heavily thinned (Tamiya X-2 White + 90% isopropyl alcohol in approximately 1:8 ratio) so it has to be built up slowly and carefully. Airbrush control is critical here because the thin watery paint has a tendency to pool and run if the brush lingers in one spot too long.
After the first 4-5 passes...
4-5 more passes...
A few more coats...
Port wing finished.
Thankfully this model is quite small so it doesn't take too long to finish the entire aircraft in white. Note the blue gloves... I've been in the practice of wearing latex gloves when doing the camo painting. It really helps to avoid those pesky fingerprints that can mar an otherwise good finish. You may also note the absence of masking on the wheel wells.
For some reason I neglected to take photos of this sequence but I did not like the look of the silver front fuselage. It was much too dark compared to the white finish. So I sprayed on a coat of Alclad White Aluminum over the existing Alclad Aircraft Aluminum... much better but I lost some contrast between panels.
I applied a bit of post shading to the panel lines and edges of the silver. Since the model wasn't given a primer coat, a few imperfections showed up around the canopy. Also some scratches resulted from me trying to remove dust caught under the paint. These imperfections were corrected and the areas repainted. Note that the repaired areas were given a spray of grey before the white, which helped blend the repaired areas into the existing white areas. Otherwise, just spraying white onto the repairs would've resulted in spots of pure white.
Almost ready for decaling!