Re: Print-ready Graphics Problem

["Ed Wurster" <eawurster -at- hotmail -dot- com>]

Comments inline.

----- Original Message ----- 
From: "Goober Writer" <gooberwriter -at- yahoo -dot- com>
To: "TECHWR-L" <techwr-l -at- lists -dot- raycomm -dot- com>
Sent: Tuesday, August 26, 2003 1:22 AM
Subject: Re: Print-ready Graphics Problem


>
> >>> ...copied a screen using ... ALT + Print Screen
> ... [saved in] Windows Paint ... [and]Photoshop
> Elements ... opened both files in Photoshop ...
> Windows Paint was a 96 ppi ... second file was 72 ppi
> ... both BMP files contained the same number of pixels
> ... file sizes are identical. <<<
>
> Right. Perfectly normal behavior.
>

You may say this is normal, but I didn't. I would call it unexpected for
most software users.

If you re-read what I wrote, you may understand the intent, which was to
point out that the same program can interpret a screen capture in different
ways. The capture is a capture, but placing or importing the file into other
programs can yield different results.


> >>> As you move forward with what appear to be
> "typical" screen captures, each subsequent program you
> use can interpret the "standard" file format
> differently. <<<
>
> That's incorrect. The file format is not at issue.
>

I don't understand why this is incorrect. I didn't say the file format was
an issue either. I said the application can interpret a screen capture in
different ways. Read on for one example.


> >>> I think this type of exercise demonstrates that
> there are pitfalls, and the software you use either
> performs the way you expect, or introduces new
> properties which must be understood in terms of what
> happens downstream in your job flow. <<<
>
> No. This exercise demonstrates a misunderstanding of
> physical image size/makeup and dpi. Dpi is an OUTPUT
> setting. It has nothing to do with the file format. It
> has nothing to do with how many pixels make up the
> image. It says "fit x many pixels into a 1-inch space
> when printed". That's it.
>

I was making a general comment about the use of software, and assumptions
that we make in order to understand and solve problems. I'm curious as to
why you took my example, and used it as an example of misunderstanding.
People learn in different ways. Learning by example is ok for some of us,
but obviously not for all.


> The reason you saw two different dpi values is because
> MS "standardizes" (my emphasis, not theirs) on 96dpi
> as a default output setting. Your Adobe product was
> apparently set to 72dpi by default. You can change the
> defaults in the application's preferences.
>

I hoped that the reader would investigate how Adobe handles screen
resolution when it creates new files. Using Photoshop Elements 2 as an
example, the application does have a preference that can be set as the
default for the next new file. However, there is also an option to create
"New from Clipboard." This always creates file at 72 ppi, even when you
change the application default for new files in preferences.

I'm using this as an example of what happens when user makes assumptions. Do
you think this illustrates the point?


> And yes, setting a different DPI setting does nothing
> to the image's file size. Why? It's a setting; a few
> numeric characters in the image format's header that
> defines how the image should be treated by either an
> output device or another application.

Yes, this is the conclusion I hoped the reader would draw. The captured
pixels in two different files are the same. The file size is the same. But
the files are different. The stored output size can be used, interpreted or
manipulated when the file is imported (or placed, or pasted) downstream.


Ed Wurster

http://www.eWurster.com/blog/
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