Acceptable dpi for 70x100 cm print

[kennylovrin]

Hey

I just wanted to ask you guys what you'd find are the lowest acceptable dpi for a print of size 70x100cm. You'd view that from a bit of distance, but do you think I could get away with less than 100dpi?

I'm trying to figure out how big I can go with pretty low res images while still keeping it "nice" from a standard viewing distance.

Are there any ways to "calculate" this?

Thanks guys!

Kenny

 

[thegman]

I just got a 32" canvas done at about 140dpi. The negative itself was not perfect, and it lacks detail up close, but from even a couple of feet away, it looks fine.

I think if it's likely to be looked at from a distance, i.e. perhaps not a hallway side wall, then go for it. Also I guess it depends on content, mine is grungy black and white, maybe a clean, colourful seascape may not have fared as well.

This may be BS, but I found this online:

http://www.diax.nl/pages/perception_printquality_uk.html

 

[Jim-st]

Acceptable for whom? Most viewers will stand back to observe a picture.

But photographers, well.... as the late Bruce Fraser used to say, "in the case of photographers, the ideal viewing distance is limited only by the length of the photographer's nose"

I always try for 180dpi, but have had good results from c.150. I think <100dpi would be pushing it, and maybe should try an uprez. Anathema to some (photographers, mostly) but probably "nice" enough from a standard viewing position. Try printing a crop on A4 and see how it looks

 

[kuzano]

Too bad you live in Sweden...

Too bad you live in Sweden...

Because here in the US, that image would only be 27X39 inches:bang:

It sounds like you are starting with a 10.8 Megapixel image file considering your desired 100dpi print res.

Have you done any looking at software used for "uprezzing" image files. There was a plugin for Photoshop called Genuine Fractals that is now called Perfect Resize 7.0. Here is a link:

http://www.ononesoftware.com/products/perfect-resize/

I've used other resizing UPREZ programs. The intent is that the software to uprez runs an interpolation routine to add pixels to get to your desired number of megapixels.

My goal when uprezzing an image is to achieve a 180 to 200 dpi desired dpi. To do that with your requirements, I would uprez the image to between 18Mp to 20Mp.

You might be able to push 10.8Mp to the desired print size with 100dpi, but that seems like a real push. It would be nicer to be able to give the printer more MP to work with.

A happy compromise might be to uprez to 15Mp and print at 150dpi.

I've had some nice results with this, but remember the nature of the image has a lot to do with how low you can pull off a print in terms of low dpi.

As the previous poster to me said... uprezzing is "anathema" to some photographers. I would have use the words "narrow minded" instead.

If you want to achieve a certain goal and the tools are available by less than desired means, but still acceptable, I call that "open mindedness" and a win-win.

I've had very good results with UpRez software. Plus Genuine Fractals was very popular and I presume with the name Perfect Resize is even moreso, since the name is more appropriate.

 

[back alley]

i wish i understood this stuff...

 

[Dwig]

I do large prints on canvas from scans of 35mm chromes on a regular basis. I work for an art gallery run by a photographer to show/sell his work. I do the scans using an Imacon and do most of the creation of master files and pre-sized files for printing.

Our "habit" is to create 300ppi files for each size print, upsampling the master files as necessary. We currently rely on Photoshop's own Bicubic functions, usually Bicubic Shaper (not Abobe's primary recommendation) but occasionally Bicubic Smoother depending on the image characteristics.

Lately, our most common print size is 29x44" (~75x110cm), but I still frequently (several a week) print 38x58 or 40x60 (~100x150cm). As a rule, these large images are printed on canvas, which we stretch and frame in-house. I find that we can get quite adequate sharpness, given the typical viewing distance of such large prints, despite the fact that the original scan would work out to something in the 120-160ppi range when printed at the 29x44" size.

There is a good series of articles over at TOP that discusses upsampling with an eye to comparing Genuine Fractals and Photoshop's Bicubic family of options. Check out the three installments:

http://theonlinephotographer.typepad.com/the_online_photographer/2008/02/its-bigger-but.html

http://theonlinephotographer.typepad.com/the_online_photographer/2008/03/its-bigger-but.html

http://theonlinephotographer.typepad.com/the_online_photographer/2008/03/its-bigger-bu-1.html

 

[kennylovrin]

Hey

Thanks for the replies!

Unfortunately I only have 6mp to work with, my idea was to try to upscale it using some of the software mentioned above to achieve somewhat higher resolution.

but with so little original data, I really doubt it will make much sense to upscale it to 18-20mp. I think I will have to go smaller print. 😉

The reason I'm asking is that a colleague of mine wants to hand some of my shots from our company holiday on the wall. But I used my R-D1 so it's a bit problematic with the sizes she wants. 😉 (This is the first time digital resolution has been a problem for me, so it's ironic that it is images that I shot with a 6mp camera instead of my 5d 🙂).

Well I guess I'll just have to manage with smaller prints.

 

[Sparrow]

i wish i understood this stuff...

... I wish other people understood it too

Just alter the image size in Photoshop or similar to whatever size you want, the program will automatically interpolate (fill in the missing bits) the image as it process it.

You may gain something by sharpening the result afterwards, but that will depend on what you're printing onto ... I have a 12x18 from a rd1 which is pin-sharp even close up.

If you are printing onto canvas it won't matter, the canvas will only have around 60 threads per inch anyway

 

[thegman]

I think the best advice here is to print a crop at the intended dpi hang it on the wall and see if it looks OK. I read that 12 or 15 dpi is not unusual for billboards, it may end up looking just great.

I would certainly do an upres, better fuzzy than pixelly if you ask me.

 

[ottluuk]

Before the popularity wave of Genuine Fractals and such, some people used incremental upsizing in Photoshop. This means when they wanted to upsize 200%, they did it in several small (10-20%) steps instead of one go and claimed to get better results that way. I'm not sure if this is still useful with today's advanced resampling algorithms but no harm in trying, I guess.

And as others have suggested, you can try printing A4 crops at various dpi values and look at them from some distance. You'll get a general idea how the texture and detail would look.

 

[Roger Hicks]

I think the best advice here is to print a crop at the intended dpi hang it on the wall and see if it looks OK. I read that 12 or 15 dpi is not unusual for billboards, it may end up looking just great.

I would certainly do an upres, better fuzzy than pixelly if you ask me.

YES!

(But don't try to fool yourself by seeing only what you want to see).

Cheers,

R.