Digital BW, The Print

I recently installed a Niagara III CIS with MIS pigment inks.
I had a tough time getting it going with lots and lots of bad nozzle 
checks and cleanings...before I learned I just had to let the thing 
rest overnight to settle down.

I find that if I don't print for a few days the nozzle checks are 
really bad and I have to do two cleanings, then run a test print to 
get the thing going.

My question is...the images from my Canon A80 routinely show as 180ppi 
when shown full size in Photoshop.  I would like to print them at a 
higher resolution, but same number of inches.  Does it do any good to 
resample for higher resolution?

Isabel

> From: Isabel Cutler [mailto:billswife_1999@...]
>
> I recently installed a Niagara III CIS with MIS pigment inks.
> I had a tough time getting it going with lots and lots of bad nozzle
> checks and cleanings...before I learned I just had to let the thing
> rest overnight to settle down.
>
> I find that if I don't print for a few days the nozzle checks are
> really bad and I have to do two cleanings, then run a test print to
> get the thing going.
>
> My question is...the images from my Canon A80 routinely show as 180ppi
> when shown full size in Photoshop.  I would like to print them at a
> higher resolution, but same number of inches.  Does it do any good to
> resample for higher resolution?

Not usually. On some printers, certain images that have fine regular detail
may result in moire if the resolution doesn't divide evenly into the
resolution of the printer. For instance, Epson desktop machines resample
everything to 720ppi and the wide format ones resample to 360ppi, using
"nearest neighbor". Dunno what Canon does. But images that show moire are
rare. Be aware, though, that fixing this only requires resampling to a
submultiple of the printer's resolution.

If you have an image that has really sharp edges in it, you might be able to
improve the sharpness of large prints by using the Genuine Fractals file
format. You save the file, then reload it at a larger resolution, and it
manages to translate some of the highest spatial frequency components
upwards so that sharp edges remain sharp at the higher resolution. But
remember that it's really inventing image data, in a manner that works well
sometimes but not always.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@...

I have not been any more impressed with Genuine Fractals than any 
other iterpolation scheme... others swear by it...

If your driver does use nearest neighbor interpolation you *should* 
gain a lot by upsampling yourself.  Image Print uses bicubic.  Don't 
know exactly what Canon or Epson uses.  I have not seen any noticable 
improvement upsampling before sending images to my 1160... but I 
haven't spent that much time testing it since I am generally happy 
with what I get and managing huge files isn't much fun on my 3 year 
old computer.

The main advantage that I can see to upsampling before printing is 
that you get a chance to sharpen your interpolated image and then 
more or less print exactly what you send your printer instead of 
letting the driver do it's magic.

Here is a sales pitch from QImage that seems compelling:

http://www.ddisoftware.com/qimage/quality/

but even using their software, my friend can't really show any *real 
world* proof that you will get better prints using this technique.

No interpolation scheme is going to be *better* for all images and 
all higher order interpolation schemes *soften* your image.

mark

...
> > My question is...the images from my Canon A80 routinely show as 
180ppi
> > when shown full size in Photoshop.  I would like to print them at 
a
> > higher resolution, but same number of inches.  Does it do any 
good to
> > resample for higher resolution?
...

Thanks, Paul and Mark...I guess I will be printing at the 180 that 
the A80 shows when I open an image directly from the card.
Isabel

I have followed this and the earlier discussion about what resolution printers resample  
images to in preparation for dithering.  

My question is as follows:  if the Epson desktop printers resample to 720ppi, is there 
any advantage to sending the printer images at 720ppi in the first place?  By this I 
mean either not downsampling below 720ppi (if enough pixels are available from, say, 
the scan to meet the required image dimensions at 720ppi) or using PS to do the up-
sampling rather than the printer driver.  I am using an Epson 2100.

> > My question is...the images from my Canon A80 routinely show as 180ppi
> > when shown full size in Photoshop.  I would like to print them at a
> > higher resolution, but same number of inches.  Does it do any good to
> > resample for higher resolution?
> 
> Not usually. On some printers, certain images that have fine regular detail
> may result in moire if the resolution doesn't divide evenly into the
> resolution of the printer. For instance, Epson desktop machines resample
> everything to 720ppi and the wide format ones resample to 360ppi, using
> "nearest neighbor". Dunno what Canon does. But images that show moire are
> rare. Be aware, though, that fixing this only requires resampling to a
> submultiple of the printer's resolution.
> 
> If you have an image that has really sharp edges in it, you might be able to
> improve the sharpness of large prints by using the Genuine Fractals file
> format. You save the file, then reload it at a larger resolution, and it
> manages to translate some of the highest spatial frequency components
> upwards so that sharp edges remain sharp at the higher resolution. But
> remember that it's really inventing image data, in a manner that works well
> sometimes but not always.
> 
> --
> 
> Ciao,               Paul D. DeRocco
> Paul                mailto:pderocco@i...

> From: Steve Kale [mailto:stevekale@...]
>
> My question is as follows:  if the Epson desktop printers
> resample to 720ppi, is there
> any advantage to sending the printer images at 720ppi in the
> first place?  By this I
> mean either not downsampling below 720ppi (if enough pixels are
> available from, say,
> the scan to meet the required image dimensions at 720ppi) or
> using PS to do the up-
> sampling rather than the printer driver.  I am using an Epson 2100.

The resampling done by the driver may be dumb, but on most images it doesn't
matter. You may find an image that results in moire, if its resolution
doesn't divide evenly into 720, but I haven't yet. If you do, then you can
use PS to resample, because it will actually do interpolation.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@...