Re: [APML] Photoshop image scaling; was: Dumb question time

["Bert Katzung" <katzung1@attbi.com>]

Hi Scott:
I agree completely.
Bert

Bert Katzung
katzung1@attbi.com
www.astronomy-images.com

----- Original Message -----
From: "R. Scott Ireland" <ireland@gate.net>
To: <astro-photo@seds.org>
Sent: Wednesday, December 11, 2002 7:33 AM
Subject: RE: [APML] Photoshop image scaling; was: Dumb question time


> Hi Bert,
>
> > maybe I'm missing something, but unless I start with a
> > resolution that
> > permits Photoshop's Scale to Fit Media to reach the paper
> > dimensions without
> > dropping much below 200 to 300 ppi, I get a very blocky result.
>
> You're not missing anything.  That's the point exactly.
>
> What we are really talking about here is how to determine the least number
> of pixels needed to make a good looking print of a given size.  The
> traditional rule of thumb has been to maintain 250 - 300 ppi at your print
> output size for maximum quality.  Craig indicates that this number may
even
> be as low as 150 ppi.
>
> If the ppi drops below whatever threshold you decide works for your
printer
> and your eyes, then you must re-sample to maintain reasonable quality.
> Photoshop's bicubic resampling works very well in this regard (checkbox
> found in the image size dialog).
>
> As I mentioned earlier, and Craig mentioned it too,  it is probably better
> to make your paper size changes in the image size dialog box (keep
> "constrain proportions" on) and not use the "scale to fit media" function,
> as this may distort the image somewhat.
>
> Also, I would not recommend applying unsharp masking or grain reduction
> until you have done your resizing.  In the event you do have to re-sample,
> this should give better results.
>
> Best regards,
>
> Scott
>
> website:  http://www.rsiphotos.com/
> email:  ireland@gate.net
>
>
>
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