What resolution for 40 x 60" canvas print?

[robgo2]

It is a landscape image that is going to be printed on canvas by a commercial lab.  I do not know what printer they use.  They recommend 300dpi generally, but that will make for a very big file with a print this large.  The print will be suspended from the ceiling or on a wall and will be viewed at distances ranging from 5 - 25 feet.

Thanks,
Rob

[Slobodan Blagojevic]

Some labs claim 100 ppi is sufficient for canvas.

[dgberg]

Almost everyone of my large canvases are all printed at 180.
For example a D800 73mb raw resampled to 40x60 @180 ppi comes out to a 445mb file.
No reason at all to go larger. (Although you could.)
You could just as easily go lower as Slobadan says.

[Bart_van_der_Wolf]

It is a landscape image that is going to be printed on canvas by a commercial lab.  I do not know what printer they use.  They recommend 300dpi generally, but that will make for a very big file with a print this large.  The print will be suspended from the ceiling or on a wall and will be viewed at distances ranging from 5 - 25 feet.

Hi Rob,

With reference to my earlier post, a rule of thumb (105-210 PPI at 1 metre, depending on subject contrast) for my average vision (with optical correction) acuity suggests 69 - 138 PPI input should satisfy a 5 feet (or more) viewing distance. Given the size of the the print, and how good they are at upsampling, you could leave the final output device upsampling to them, or do it yourself to whatever their equipment PPI requirements are. Something like 11-46 MPix as input, before final output device resampling, should do.

The benefit of resampling yourself is that you have control over the output sharpening that needs to be applied after the upsampling.

Cheers,
Bart

[Slobodan Blagojevic]

Bart,

I assume your rule of thumb refers to glossy prints (the most demanding for sharpness)? Canvas prints, due to their surface texture, should be more forgiving, no?

[Bart_van_der_Wolf]

Bart,

I assume your rule of thumb refers to glossy prints (the most demanding for sharpness)? Canvas prints, due to their surface texture, should be more forgiving, no?

Hi Slobodan,

Maybe. IMHO it depends a lot on the particular structure. In my experience, canvas is also capable of showing considerable detail, especially where the structure is relatively flat (maximum depth or height) instead of on a texture slope of a fiber.

My tests of other (e.g. matte) media, in a search of potential negative effects on output resolution when printing my resolution test target on less reflective surfaces (to avoid distracting reflections), shows me that resolution doesn't suffer as much as some would like us to believe. Even on matte media (e.g. Hahnemühle Photo Rag Matte FineArt, which has some structure), it can still resolve single line spaced 600 PPI structures. The only thing canvas adds is a bit of a slope where the detail is printed, but other than changing direction, it doesn't really diffuse that much (unless it is very coarse). The surface structure adds a bit of randomness, a visual distraction that can hide only a bit of the lacking detail. IMHO, of course ...

I do know that I'm a bit more critical than most ...

Cheers,
Bart

[canvaspro]

Dan hit it on the head.  Size your canvas to the size you want it to be printed.  Contact your lab if you are doing an image wrap because you may need to crop the image so that it is 3 - 3.5" larger than print size for the depth allowance.  Then change your DPI to 180.  Canvas prints beautifully at 180 DPI and anything higher just isn't necessary.

Best of luck,
Eric

Canvas Press

[Schewe]

My tests of other (e.g. matte) media, in a search of potential negative effects on output resolution when printing my resolution test target on less reflective surfaces (to avoid distracting reflections), shows me that resolution doesn't suffer as much as some would like us to believe.

I agree as it relates to matte vs. glossy and the need for good (optimal) resolution. Clearly, it's easier to see the differences between lower and higher resolution output on glossy media, but depending on how smooth the surface of the matte media is, something like a hot press fine art paper can use just about as much resolution as you can through at it. When you get an irregular surface like a cold press watercolor paper, the texture is more "forgiving" of lower resolution images, but the question is, what is "good enough". I think that depends on the media and the image.

I really don't have enough experience printing on canvas to say much about optimal and minimum resolution for canvas...all I know is I've seen a lot of canvas prints that look really good with lower than optimal resolution and I've seen a lot of canvas that looks like crap with lower resolution. A lot comes down to the image, what sort of texture it has, how well the original capture was made and the noise and sharpening applied and how the image was resampled for the final printed size and what resolution the printer was set for. I would say that 180PPI for the image rez would be a minimum...some people claim that setting the printer rez to 720 (for Epson) is "good enough" for canvas...but I'm not sure, I just don't have the experience...