What is the maximum print size of an image that will retain perfect image quality in a canvas print?
This depends on a number of factors like exposure, illumination, camera shake, and resolution.
But a simple thumb rule will give you the idea about print size from your digital image. Just divide the image length in pixels by 70 and you will get the approximate print length in inches, and similarly for image width. So if your image size is 2800 pixels by 2100 pixels, you may expect an enlargement up to 40″ by 30″.
The megapixel count of your camera too can give a rough approximation of the highest print size at good quality. A 5 megapixel camera, with an image size of 2580 pixels by 2048 pixels, will give you a 36″ by 28″ print at most. For a 7 MP camera (3072 pixels by 2304 pixels), the print size can go up to 44″ by 32″, whereas a 10 MP camera (3648 pixels by 2736 pixels) can let you shoot photos for prints up to 48″ by 40″.
All said and done, if the original image is good enough then the prospects of producing a perfect canvas photo print are actually much brighter.
Always shoot at the maximum image size that your camera allows
Try to make sure that the shot is not over or underexposed and the subject is evenly illuminated.
Try to pick the highest ISO rating. Your camera might choose a default ISO setting according to the situation; you need to use manual override and set ISO 100 and ISO 200.
Setting low ISO could result in camera shake. Make sure that Image Stabilization in your camera is turned on.
Use a tripod as often as possible. If it is not practicable in some situations, try to lean on a wall or a tree. Remember, your legs plus such a support makes a tripod!
Practice holding the camera steady. Holding your breath at the time of releasing the shutter is one good trick.
Use pre focus by half pressing the shutter release button. This reduces shutter lag, and also the chances of camera shake since shooting time is reduced.
If your camera has a viewfinder, whether optical or electronic, look through that instead of the LCD screen at the moment of shooting. Holding the camera away from the body is a less stable position than holding it close with elbows resting against your body. If you prefer using the friendlier LCD screen, switch to the viewfinder after composing the shot.
Shooting and providing the image in PNG, TIFF, RAW or PSD format wherever possible ensures that image quality is better. JPEG is the most popular format, but its image compression increases contrast and a lot of image data is lost.
Finally, you need to find a canvas giclee printer who is willing to devote the time and painstaking effort to touch up your image just so subtly so that it is ready for that perfect enlarged print on canvas.
Happy shooting!
Matthew Barton writes on various topics of photography and you can find his work here Pictures on canvas, Fine Art reproduction and Giclee Printing