Question about canvas size

I've got a 150 cm x 120 cm project coming up that I want 300 dpi. I did a few experiments initially doing it at 25% of the final size at 300 dpi and then using enlarging software (in this case Alien Skin Blowup Photoshop plugin) to bring it up to the final size. It seems to work quite well at retaining the brush detail.

Mind you I will have to work with a small brush when doing the 25% original as the brushwork will look way too big and not realistic on the final copy if I don't.

Hope this helps

Frank

I have a question regarding this issue.

May I ask you if using the image resize feature available in Rebelle with a higher dpi. Rebelle will recalculate and apply new dpi. 

Like for example from A3 150 dpi to Poster 300dpi without loosing quality during the printing process?

Thanks,

Annalisa

Or even A3 300 dpi t A1 Poster 300 dpi. On the screen, it looks right. Do you know if in printing size it will lose quality?