Notes on the "Enter Magnification" Photoshop-Compatible Plug-in
Downloaded from ReindeerGraphics.com

The purpose of this plug-in is to provide a simple facility for microscopists 
who use Photoshop to acquire, process, analyze and/or print their images to 
be able to place magnification bars on them. The procedure is to enter the 
image magnification from the keyboard (along with the desired length of the 
magnification bar in microns and the dpi or "dots-per-inch" of the scanner or 
camera used to acquire the image). The program then draws the bar in the 
lower right corner of the image, and labels it, using the current foreground 
and background colors. The plug-in adheres to all Photoshop interface 
requirements and should work in programs such as Image Pro Plus, Paint Shop 
Pro, etc., that obey these conventions.

This plug-in is compatible with, but does not require Fovea Pro or the Image 
Processing Tool Kit. The plug-in is freely downloadable and usable in 
Photoshop and compatible programs, but we request that it not be distributed 
further by users; instead, those wishing to have their own copy should 
download it directly from the ReindeerGraphics.com web site (which will ensure 
that they get the latest version). Both Macintosh and Windows versions are 
available on the web site. The file should simply be placed into the same 
folder with other Photoshop plug-ins, and will appear under the Filter menu 
when the program is next launched.

When the user enters the image magnification (e.g., 1000X), the dpi of the 
camera or scanner used (e.g., 300 dpi), and the desired length of the 
calibration bar (in micrometers), the program calculates the length of the bar 
(reported in pixels). If this is more than 10 pixels and less than the width 
of the image, the bar is drawn in the lower right hand corner and labelled 
with the length, using the currently defined foreground and background colors.

The plug-in saves the entered calibration (pixels per micron) and units 
(microns) for use by the other plug-ins in Fovea Pro and The Image Processing 
Tool Kit, over-writing any other calibration already in effect. This 
information is saved in a file (IPTKPREF) that is used by the other plug-ins 
in Fovea Pro and the Image Processing Tool Kit. If you do not have those 
programs installed, you can simply ignore this file.

A Photoshop 6 Action including this operation can be created and then applied 
either with a function key or as a batch operation to a folder full of images.

The plug-in was written in response to perceived interest as expressed in 
various user forums such as the Microscopy and Microanalysis listserver. It 
does not at present allow for units other than micrometers (although the Tool 
Kit and Fovea Pro do), nor for arbitrary placement of the micron bar 
(although Photoshop cut-and-paste can obviously be used afterwards). If these 
or other enhancements are desired by a significant fraction of users, please 
let us know. Comments and questions can be directed to DrJohnRuss@AOL.com

We hope that while visiting the ReindeerGraphics.com web site you will also 
look at the many other powerful routines for scientific image processing and 
measurement that are available as Photoshop plug-ins, and read the active 
discussion of methods that takes place on our bulletin board.

John and Chris Russ
