Archived posting to the Leica Users Group, 2001/04/10

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Subject: Re: [Leica] Photoshop help
From: Johnny Deadman <john@pinkheadedbug.com>
Date: Tue, 10 Apr 2001 09:43:40 -0400

on 4/10/01 8:14 AM, Gwpics@aol.com at Gwpics@aol.com wrote:

> I think your problem may be that you are saving at 71 dpi and not 72 dpi thus
> causing a moire effect withthe bands of the monitor. You will always be
> liable to get some mismatch if there are fine lines in the image (I get
> problems for instance with roof tiles on buildings I photograph for my
> clients) but it should not generally be a problem. But I think that 1 dpi
> could be the problem.

I don't THINK this is the problem as the web is blind to dpi and just looks
at the pixels. So 71 dpi is the same as 72 dpi is the same as X dpi. However
worth a try. 

I think saving at 5 quality IS a problem, as I find anything less than 7
gives troubling artefacts. Even at 7 any areas of very fine tonal gradation
like broad highlights (flat skies etc) are going to give posterisation.
That's just jpegs for you.

As a guideline, saving at 7 or 8 quality, an 800 pixel wide jpeg of a
monochrome image will save at about 60k for me, an RGB image more like
130-150k.

Finally, check that your browser isn't set to display colors in some strange
way, like 256 colors or something, as this will result in dithering that
will be really nasty. Check your image in another image editor before
blaming Photoshop. If it looks okay then the problem is with the way your
browser is set up.
- -- 
John Brownlow

http://www.pinkheadedbug.com

Replies: Reply from "Jason Hall" <JASON@jbhall.freeserve.co.uk> (Re: [Leica] Photoshop help)