Newsgroups: comp.graphics
Path: utzoo!utgpu!topix
From: topix@gpu.utcs.utoronto.ca (R. Munroe)
Subject: Re: TIFF better than PICT?  Why?
Message-ID: <1991Jan5.035444.28219@gpu.utcs.utoronto.ca>
Organization: UTCS Public Access
References: <1991Jan3.065804.17254@msuinfo.cl.msu.edu> <1991Jan4.020120.16318@gpu.utcs.utoronto.ca> <1991Jan4.171654.6337@msuinfo.cl.msu.edu>
Date: Sat, 5 Jan 91 03:54:44 GMT

In article <1991Jan4.171654.6337@msuinfo.cl.msu.edu> raja@cpswh.cps.msu.edu writes:
>
>I'd like to thank everyone who posted those
>extremely informative follow-ups to my first
>question about PICT-2.
>
>Actually, the reason I asked those questions
>was in the hope (unsuccessful so far) of answering
>a different question.  So maybe I could just
>ask the original question itself:
>
>I have been using a flatbed scanner (Howtek
>Scanmaster) with Laserpaint II on a Mac, to
>scan images in 24-bit color.  Now, Laserpaint II
>allows you to save the scanned images in many
>different formats, such as PICT, TIFF, or
>encapsulated PostScript.  At first I used to
>save them in PICT format.  Someone told me that
>"PICT loses information" and that TIFF would
>give better results.  (This turned out to be
>true.  The very same image, saved as TIFF
>and transferred to a Sun, is much superior to
>a version saved as PICT).  Why so?
>
>Thanks in advance (again),
>
>
>Narayan Sriranga Raja.

Newsgroups: comp.graphics
Subject: Re: TIFF better than PICT?  Why?
Summary: 
Expires: 
References: <1991Jan3.065804.17254@msuinfo.cl.msu.edu> <1991Jan4.020120.16318@gpu.utcs.utoronto.ca> <1991Jan4.171654.6337@msuinfo.cl.msu.edu>
Followup-To: 
Distribution: 
Organization: UTCS Public Access
Keywords: 

In article <1991Jan4.171654.6337@msuinfo.cl.msu.edu> raja@cpswh.cps.msu.edu writes:
>
>I'd like to thank everyone who posted those
>extremely informative follow-ups to my first
>question about PICT-2.
>
>Actually, the reason I asked those questions
>was in the hope (unsuccessful so far) of answering
>a different question.  So maybe I could just
>ask the original question itself:
>
>I have been using a flatbed scanner (Howtek
>Scanmaster) with Laserpaint II on a Mac, to
>scan images in 24-bit color.  Now, Laserpaint II
>allows you to save the scanned images in many
>different formats, such as PICT, TIFF, or
>encapsulated PostScript.  At first I used to
>save them in PICT format.  Someone told me that
>"PICT loses information" and that TIFF would
>give better results.  (This turned out to be
>true.  The very same image, saved as TIFF
>and transferred to a Sun, is much superior to
>a version saved as PICT).  Why so?
>
>Thanks in advance (again),
>
>
>Narayan Sriranga Raja.

It would be helpful if you could describe the differences.  Are the PICT images
banded or dithered?  If so, they are probably not 24-bit images - which would
explain the lower quality.

There are a couple of reasons why the images might be 8-bit:

1.  The scanner software was developed before 32-Bit Color QuickDraw was 
    released.

2.  The scanner software is looking for 32-Bit CQD but it is not installed
    so it falls back to saving PICT files in 8-bits.

There is no reason that a 24-bit TIFF image should look any different
from a 24-bit PICT image - especially if they were created with the same
software (case in point: PhotoShop).

Bob Munroe
topix@utcs.utoronto.ca