Pinarello decal work
If you don’t have access to high quality automotive paint and a spray booth, you can get good results painting sections of a downtube with a high quality spray enamel.
Mask off the area with blue painters tape. Wet sand up to 1000 grit then start with a good primer. You want to get rid of the pits and pockets for the decals. Move on to about five coats of a high quality lacquer or enamel. Next step is most important and often neglected. Wet sand with 1000 grit sandpaper and then buff with white automotive rubbing compound. This will creatimg a glossy smooth surface for the decals. If you don’t do this, you will get air pockets under the decals.
Wait about 1 week. You want to give the paint time to harden and de-gas. Then, apply decals and coats with duplicolor crystal clear enamel. Laquer is took aggressive for decals. You may choose to wet sand at this point, but I was happy with the results without it.
This method works well for unique situations where you have sections with different colors. You could do this to the whole frame, but it will be labor intensive and the paint with easily chip. If you want a repaint, pay someone and do it right with automotive polyurethane (if you also want decals under clearcoat) or get it powdercoated for about $150 (most durable, but no decals or clearcoat option).