They are easy to locate one Moon diameter to the northeast of Beta Canus Venaticorium. Both are reasonably bright and fairly easy to pick out even in light polluted skies. NGC 4490 is visual magnitude 9.8 and NGC 4485 shines less at magnitude 12.5.
Since the view was pretty good, I decided to capture them in a sketch after a long look.
Date and Time: 06-08-2013, 04:30-04:50 UT
Scope: 13.1” f/6 Dobsonian. 21 mm wide field eyepiece 95X
8”x 10” 400 series black Strathmore Artagain paper,
white Conte’pastel pencil, a blending stump, plastic eraser.
Seeing: Pickering 7/10
Transparency: Average 3/5
Temperature: 50°F ( 10°C )