Notes on the Macintosh ColorPos Photoshop Plug-In, Version 1.02a 3/30/8
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Version 1.02 introduced ColorPos to the Mac.  At this point we have not found the time to produce a ColorPos for Mac manual, but we have decided not to delay the release any longer.  For those of you impatient with instructions, you may skip to Installation below and probably be OK.  The operation of the Mac version is very similar to ColorPos for the PC but the Mac-specific parts are similar to ColorNeg for the Mac.  The manuals for these are available on our web site<br>
http://www.c-f-systems.com/Plug-ins.html<br>
and we have placed any leftovers in the Addendum manual.  Please understand that ColorPos never requires the new Scantique plug-in mentioned for use with ColorNeg.
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ColorPos 1.02 is an Adobe Photoshop plug-in intended to maintain color integrity while making the initial, largest corrections to a positive image, such as a scanned image of a color slide or a print, or an image from a digital camera. ColorPos is distributed as a fully functional demo version on our web site (http://www.c-f-systems.com/Plug-ins.html).  ColorPos has tools that can be used to characterize problem images.  For more critical work there is a comprehensive color balance system with CC (color compensation) filter readouts, familiar to many photographers. 
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ColorPos 1.02 introduced a real breakthrough in the ease with which satisfactory results can be obtained from problem positives with checkered histories.  Click a gray area - preferably very light gray to nearly white - and slowly scroll the FilmData control.  When the overall image looks best, you have a Film Type number for that negative.  Version 1.02a introduces the ability to adjust color balance by directly scrolling CC (Color Compensation) values or even by typing in CC values.  The CC concept is central to understanding three-primary color photography systems, which, after all, is what you are working with whether you use film or a digital camera. Your images may contain "millions of colors" but every single one of those millions of colors is a mixture of just red, green, and blue.   See the Addendum Manual for a complete description of CC scrolling and entry and FilmData control.  
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The Macintosh version of ColorPos requires OS X to work and has been tested with Photoshop 7, Photoshop CS, CS2, and CS3 on the PowerPC platform and with Photoshop CS3 running native on the Intel platform.
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The following explains the basics of using ColorPos.  The manual has more detail on these basics as well as a clickable Descriptive Table of Contents guiding the reader to full explanations of the many powerful features that are also available in ColorPos including the ability to easily match a series of pictures taken under similar conditions.
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Installation
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Download the zip archive ColorPosMac102.zip file.  Expand the zip file into a folder on your desktop.  Locate the proper plug-in file archives for your Mac/Photoshop combination:
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Photoshop 7,CS, or CS2: ColorPos.plugin CW.zip<br>
Photoshop CS2 or CS3 PowerPC: ColorPos.plugin XC PPC.zip<br>
Photoshop CS3, PowerPC or Intel: ColorPos.plugin XC UNI.zip<br>
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Note that with some versions you have a choice. 
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Put the proper ColorPos plugin archive (zip) file in the Photoshop filters folder, which typically can be found by clicking Applications, double-clicking Adobe Photoshop x (where "Photoshop x" specifies the version of Photoshop), then double-clicking Plug-Ins and finally double-clicking Filters.  Put the zip archive in the Filters folder and double-click to release the ColorPos.plugin file.  Photoshop will automatically configure for ColorPos the next time it is started.
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Auxiliary Files
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Of necessity ColorPos for Mac uses an odd convention for the folder location of the other files found in ColorPosMac10.zip, such as ColorPos.colorintegrity and colorintegrity.grayscale.  The location varies with the version of Photoshop, please see the manual, Installation, for full details.  (For the present, the ColorNegMacManual will give you the information you need.)
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Obtaining the Raw Image
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The working file must be in 16-Bits/Channel RGB mode (scanners which scan at 12-Bits/Channel and produce a 16-Bits/Channel file are fine).  Most scanners deliver positive scans as "gamma-corrected" images by default.  "Linear" scans are also permitted - in fact, encouraged - but are not required.  (If the scan is linear, ColorPos must be informed by checking the Linear Input checkbox - see under Selection Control Panel).  A linear scan will look very dark or otherwise strange but ColorPos will fix that.
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If the original is produced using Photoshop RAW, the objective is to read as 16-Bits/Channel and do as little damage to the image as possible before sending it to ColorPos.  Our normal procedure is to set Brightness (which is not actually brightness) to 50, which we believe is the most neutral value.  Set Contrast, Saturation, Exposure, and Tint to 0.  Don't even think about using the "Calibrate" settings in RAW.  Set them all to zero.  They seem specifically designed to destroy color integrity.  If you are having trouble getting highlight detail, set Exposure to a negative value, like -0.5 or -1.0.  (See <br>http://www.c-f-systems.com/16BitSecret.html for further details.) 
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Some versions of Photoshop RAW have a "Curves" tab with a selection on a pulldown called "Linear."  "Linear" is the selection that you want, but do not be fooled.  This is another case where Adobe has chosen to take a term with a well-established meaning in the field and have it mean something else.  What you get by selecting "Linear" here is actually a "gamma-corrected" image, so do NOT check ColorPos's Linear Input checkbox.  In this case "Linear" mearly means that you are avoiding yet another opportunity for RAW to distort the image colors.
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If the scanner or digital camera will not deliver a 16-Bits/Channel image, it is permissible to convert an 8-Bit/Channel image to 16-Bits/Channel using Image->Mode->16-Bits/Channel (this is not true for the companion plug-in ColorNeg).  If you must convert an 8-bit image, the manual has several rules which will lead to better results if they are followed.  
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Starting ColorPos
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Once you have a good 16Bits/Channel image in an active Photoshop window, the rest is simple.  From the Photoshop Filter menu: Filter->C F Systems->ColorPos.  The C F Systems entry should be near the bottom of the Filter menu.  There will be a short delay as ColorPos builds tables describing the image, then a dialog will appear.
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At this point the image should be nearly correct - sometimes it is satisfactory as is.  To explore the next, simple level of ColorPos capability, you will see to the right of the scrollbar control a checklist of ScrollBar options.  "Lightness" should already be checked.  Use the scrollbar to set the approximate lightness you desire for the image.  If the color balance needs to be adjusted, the easiest and often most effective method is to find a patch in the preview image that should be gray (colorless) and click on it.  "Gray" can be anywhere from quite dark to nearly white but avoid areas that are completely white.  If possible, click several gray patches and see what happens to the image, choosing the best result.   
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With a good positive image, in most cases that is all that is required for satisfactory results.  However, ColorPos has many features designed to give you a high degree of control over the appearance and quality of your color photographic images while retaining the color integrity of the image.  See the manual for more information.  
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Demo Version
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ColorPos is distributed as a demo version our web site (http://www.c-f-systems.com/Plug-ins.html).  The demo version of ColorPos embeds a gridwork in the images it produces.  In general, this gridwork is not obtrusive enough to prevent evaluating the results and in fact we expect that some less critical users may find the results usable as is.  To unlock the demo version and eliminate the gridwork, a key code may be purchased via our web site: <br>
http://www.c-f-systems.com/Plug-ins.html<br>
where you will find a paragraph starting in larger type:<br>
"Purchase ColorNeg and ColorPos for Mac." <br>
Clicking this will take you to a secure site where you can purchase a "ColorNeg for Mac Family" key code. The SAME key code can be used on up to three computers owned by the same person or company and will unlock the Mac versions of ColorNeg and Gamsat (if and when GamSat becomes available - we do currently plan to issue it) as well as ColorPos.