Re: [Gimp-user] help & gray threshold



On 01/17/2013 07:42 PM, Thomas Widlar wrote:

1. I've just downloaded and installed GIMP and GIMP help system for
Win7. When I hover over the action buttons or options, I'm told to
press
F1 for help, but no help comes up. What do I need to do sto connect
GIMP
to its help.

2. My first task is to upgrade some music pages for a composer. He has
grayscale PDFs. The music scanned well but the horizontal staff lines
are a light grey, clear but light. How do I make any pixel darker than
certain threshold value black? How do I set that threshold?

I have no experience with GIMP, just some minimal experience with
MSPAINT. But I'm happy to learn.

Wow, you are starting from "ground zero" here!  But that means
things can only get better - and better, and better.

First thing is to open your PDF files in the GIMP.  You did not
mention a problem with this but if there is one, you might have to
install and configure Ghostscript.  If so, see:

http://sourceforge.net/projects/ghostscript/
http://registry.gimp.org/node/25039 [for this purpose EPS = PDF]

The Threshold tool, for converting grayscale (or other) images to
2-color black and white is at:  Tools > Color Tools > Threshold

Also of interest, a much more subtle tool is the Color Curves one,
at Tools > Color Tools > Curves.  Dragging the diagonal line down at
a point 1/3 of the way in from its left end, and dragging it up 2/3
of the way from its left end, will make the contrast between dark
and light regions much stronger - play with it to see what it can do.

At the top of the Threshold and Curves windows you will see a drop
box labeled "Presets."  This stores a history of past adjustments.
When you find a setting that is "just right," you can reload it by
using this drop down list and selecting the one you want for e-z
consistent results.

And another thing to get used to:  If you do File > Save, the GIMP
will save your file as an .XCF file, which is the GIMP's own native
file format.  To "save as" a PNG, JPG, etc., do File > Export.  In
the dialog that comes up, you can choose the format to save your
file in just by naming your file with the correct extension, i.e.
"example.png"  The GIMP will present the options for saving the file
- i.e. compression / quality, embedded comment if any, etc.

GIMP 2.8 is a fairly new release, and a lot of the newer features
don't have help menu entries yet.  On the other hand, you will find
a lot of very useful tutorials on YouTube.  And of course, if you
are really stuck, you know where to ask.

Welcome to it!

:o)

Steve






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