Re: dpi of scans/jpg's: 300 or 72?

I just finished a Photoshop class taught by one of the printing companies my
office uses and learned a few interesting things that may help at some
point.

1.  When scanning (for print), scan at a resolution of 300 dpi times the
enlargement/reduction factor.  For example, if you have a 3x5 picture and
you want to use it for print at 3x5, scan it at 300 dpi.  If you want it to
use it for print at 200% of the original size, scan at 600 dpi.  If you want
to use it for print at 50% of the original size (and you know you'll never
want to print it bigger), scan it at 150 dpi.  After sizing it to what you
want in Photoshop, resample it to 300 dpi.  Never give them anything larger,
it will take too long to rip and will not look any better.  Don't give them
anything smaller, it won't look good.

2.  If you're not sure, scan it at too high a dpi and let Photoshop
downsample it to 300.  NEVER UPSAMPLE A GRAPHIC.

3.  Never give a printer a jpeg.  Never give a printer a jpeg.  Never give a
printer a jpeg (our teacher repeated this three times to make sure we
remembered it).  Save all your scans as tiff's and convert the tiff's to
jpeg.  Save the tiff's in case you need to print them at some point.

We're just beginning to do all the layout, design, scanning, etc. of our
corporate magazine in house and we've decided to scan all photos smaller
than 8x10 at 600 dpi to be put in a photo library.  That way, if we wish we
had a bigger copy of a photo, we'll have it.  And I can just downsample
everything to 72 dpi for the web.

Oh, and one more thing.  The color ink jet/laser/solid ink printer in your
office is probably not calibrated correctly.  So when you print a proof on
it, then send your job to the printer and the colors look completely
different, it's because YOUR printer is printing incorrectly.  Theirs is
most likely printing perfectly.  To check, make a box and fill it with 60%
Cyan, 50% Magenta, 50% Yellow and 12% Black.  When this prints, it should be
a perfect gray.  If it looks pinkish or greenish or blueish, your printer is
off.  HP ink jets are notorious for this.

This may not be of any use for those of you who never need to deal with
printed media, but for those of us for whom art needs to do double duty,
this may be of some use.  Printers can be really rude to web people, so
maybe this will save some of you from getting yelled at.  And if your
printer does yell at you, take your business elsewhere ;-)

Mike Eovino
Webmaster
Estes Express Lines
http://www.estes-express.com

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