Digital BW, The Print

> Hi,
> 
> > Austin, thanks for asking - replies inline...
> >
> > > BH,
> > >
> > > > I did a series of tests with my printer, a 1270 using the Epson
> > > > driver.  Short answer: 360 or 720ppi print noticeable better
> > > > than any other resolutions.
> > > >
> > > > Long answer:
> > > > I'm fairly picky.  I usually don't enlarge beyond 4-5x in the
> > darkroom.
> > > > I look at prints from 6" away.
> > > >
> > > > The _image_ resolutions I tested were: 840, 780, 720, 660, 600, 540,
> > > > 480, 420, 360, 300, 240, 180ppi, 8-bit grayscale images printed from
> > > > Illustrator.  I created the different resolution versions by
> > starting at
> > > > 840ppi, and downsampling to each successively lower resolution in
> > > > Photoshop.
> > >
> > > How do you know the downsampling isn't causing the visual
> > difference in the
> > > printout?
> >
> > The image files show no artifacts or moire on screen at 100% pixels.
> 
> OK...but that doesn't mitigate that this is a possibility.
> 
> > >
> > > > My test  image had some thin slightly diagonal lines
> > > > (wood joints) which helped identify differences.  The thing that
> > > > immediately stands out is moiring(?) in these lines at image
> > resolutions
> > > > other than 360 or 720ppi.
> > >
> > > What was the actual original image scan resolution?
> >
> > It was a 6x7 TMX neg scanned @ 3200ppi on an Epson 3200, no
> > "Epson sharpening"
> > applied.
> 
> But what was it printed at, with no downsampling/resampling etc?
> 
> > > > Anyone else have experiences to support/contrast this?
> > >
> > > My tests show that scanning at the native optical resolution of
> > the scanner,
> > > and resizing the image without decimating the image (resampling) yields
> > > noticeably better results than resampling.
> > >
> > > Did you try printing one with no resampling?
> >
> > No, do you mean setting the print size to various resolutions,
> > and printing each?
> > (Each test would be at a different magnification)  I'll give this a try.
> 
> No, simple as printing it the same size as the other prints you made, just
> leaving the PPI to the printer fall where it may.

Ah - I understand now.  At the test's printed size, the image resolution would have 
been 
2400 ppi.  Making a print from this resolution shows no moire effect.  Of course, the 
image is only ~3x3.6"...  I also tried printing a small area of the 
image with no resizing at a particularly bad resolution: 540ppi.  This print shows the 
moire as well, although it is somewhat obscured by the softness of the image at this 
magnification.  

- Brian