Suggested resolution to use for illustrations + lagginess when using brushes
What resolution do you suggest I should use for illustrations? I am currently using 640 dpi however I feel that a high resolution would create a lot of lagginess when I use big sizes for brushes like: airbrush and watercolour. I really want to know how I can reduce those lagginess because I prefer shading smoothly without any lagginess to interrupt it.
Resolution doesn't mean much if you don't say the canvas size. Canvas size and resolution go hand in hand. For example: a canvas that is 7 inches by 10.375 inches at 445 ppi is identical to a canvas that is 10.375 inches by 15.75 inches at 300 ppi.
To determine the best resolution for your work, you need to decide what the illustration will be used for; how will it be viewed? If you are printing the illustration then 350 ppi at print size should be enough for color work. 350 - 600 ppi for line art.
If you plan to post your work online then you need to determine what the optimal resolution for artwork online is. For example: the iPad 12.9 inch Pro has a resolution of 2732 X 2048 pixels (240ppi).