Auteur: David G
Date: 20-10-2005 08:40
NEGPOS plug in pour photoshop quelqu'un connait ?
http://www.c-f-systems.com/Plug-ins.html
AutoNegPos 1.0 Notes 9/9/5
Will automatically convert scanned negative images to positive images and preserve color integrity. This AutoNegPos demo will work for 30 days after first usage. To use AutoNegPos after that, you will need to purchase a key from our web site. The key can also be used with several other related plug-ins that are available.
http://www.c-f-systems.com/Plug-ins.html
1. Install the AutoNegPos.8bf in the Photoshop "Filters" folder. See "Installation" below if you need more detailed instructions.
2. You MUST set your scanner to deliver a 16-bit/channel image (that is, 48-bit color rather than 24-bit color). This is not optional. A Linear scan is also greatly preferred. See "Scanning the Negative" below for more information.
3. With a scanned negative image loaded into Photoshop, use the menu item Filters--C F Systems--AutoNegPos. If this filter is grayed out, please review step 2.
4. AutoNegPos has two basic controls, brightness and color. Click the checkbox next to Brightness and the scrollbar will control image brightness, with values 0 - 100. Click the checkbox next to Color and the scrollbar will affect the image color with values 0 - 100. The effect of the brightness control will be roughly similar with all images. The amount of color control will vary from image to image and should be set where the result is most pleasing or natural. The default setting will be satisfactory in the majority of cases.
5. Film Class refers to the general type, brand, and speed of the negative film being scanned. There are six radio buttons named A - F which cover a wide range of commonly used films. Test five or six negatives of the same type of film, using different selections from A-F and varying the brightness and color for each. Usually one setting, say B for example, will be noticeably better than the rest for almost all the negatives in the group. In the future, leave the setting on B for that type of film. If you use more than one type of film, do the same experiment, choosing the letter that works best for each type. Once you have found the best setting for a film type, leave the film class setting alone and do not try to adjust it for individual pictures.
6. That's it. AutoNegPos will hold the A - F setting so the same setting will come up the next time you use AutoNegPos. The check boxes for Hold Over provide this same feature for Color and Brightness. We find it most useful to check the Hold Over box for Brightness, but to let the Color setting be reset to the default each time.
For many commonly used films, AutoNegPos works very well for most negatives, works satisfactorily for the vast majority of negatives and works very poorly for a few negatives. If you find AutoNegPos limiting, you may be ready to try NegPos. The paid version of NegPos will accept the same registration key that you buy for AutoNegPos. NegPos gives you much more complete control over individual negative inversion and also has the tools necessary to calibrate the film types you use to give more accurate inversions. You also can use NegPos calibrations to set up AutoNegPos so that A - F are calibrations tailored to the films you actually use.
When you register AutoNegPos, the "Register" button will change to a "Load Data" button, allowing you to load a "*.negpos" file having calibrations produced by NegPos as explained in:
http://www.c-f-systems.com/Docs/NegPosManual121.pdf
The calibrations are loaded in alphabetical order and the first six replace Film Classes A - F. (The ordering can be readily controlled in NegPos by giving the film calibrations names like "A Kodak ...", "B Fuji ...", etc.)
Installation
We have not provided an installation program, but have taken the same approach as Adobe has in distributing "RAW" conversion plug-in revisions. You have downloaded a zip file which contains these notes and a file AutoNegPos.8bf. All that needs to happen is the AutoNegPos.8bf file needs to be put in the Photoshop filters folder. For an all-default installation, that folder will be
C:\Program Files\Adobe\Photoshop x\Plug-Ins\Filters
where "Photoshop x" specifies the version of Photoshop. If your installation is not the default, you probably already know how to find the corresponding filters folder on your system. If you are unable to find the folder we suggest using the Windows "find files or folders" to locate it. Find files or Search is on the Start menu, and a search for file names of "*.8bf" should locate the folder. The Filters folder should have a number of other files with 8bf extension already in it. Once the AutoNegPos.8bf file has been placed in the folder, Photoshop will automatically configure for AutoNegPos the next time it is started.
Scanning the Negative
Getting a good result requires a good scan of the negative. You MUST set your scanner to deliver 16-bit/channel image (that is, 48-bit color rather than 24-bit color). Yes, Photoshop will convert an 8-bits/channel scanned image to 16-bits/channel, but this will lead to results that are poor and lacking in shadow or highlight detail or both. If your scanner has a native bit depth of only 12-bits or 14-bits/channel, that will usually be sufficient if the scanner will automatically deliver this in 16-bits/channel format. It is also very desirable to scan in "Linear" mode if at all possible. The "Linear Input" box in AutoNegPos is checked by default. If you find it impossible to do a Linear scan, uncheck this box and AutoNegPos will do the best it can to work around this failing.
A good scan will look a lot like the negative you are scanning. It will be a negative image and usually dark; often quite dark if the scan is linear. Some scanners have special provisions to scan negatives. While some of these work reasonably well, in general they are better avoided. Scan the negative just as you would a positive slide, the one difference being that you want a linear scan. Usually scanners have highlight and shadow adjustments. For Linear scans these adjustments should either be off or set so that the highlight and shadow clipping points are far enough outside the image histogram so that no actual clipping of highlights or shadow pixels occurs. If the scan is not Linear, the highlight and shadow adjustments should always be turned off.
Film Scanner
Most film scanners have 16-bits/channel Linear scanning as a specific option. Make sure any highlight or shadow adjustments leave the complete histogram of the scanned image intact and do not clip off any highlights or shadows. It is usually best to scan the negative as though it were a slide.
Flatbed Scanner
Some flatbed scanners have 16-bits/channel Linear scanning as an easily accessible option, but the method for making these settings is different for nearly every scanner and often is quite obscure. It is usually best to scan the negative using the settings for scanning positives (slides).
As all scanners are different, you will need to do some hunting to find the correct settings. As an example, with many recent HP scanners, you will find in the TWAIN interface a Lighten/Darken control. This control has a Midtones setting that defaults to 2.2. To get a Linear scan, set this so-called Midtone to 1.0. While you are at it, set Highlights to full scale (usually 255) and Shadow to minimum (usually 0). To obtain 16-bits/channel scans, you have to go outside the TWAIN interface, to the general interface program provided with the scanner and there you need to hunt until you find an option to "scan at maximum pixel depth," which means 16-bits/channel. Then restart Photoshop so the change will be recognized for the next scan. On the principle that most scanner software is better designed than HP's, this may give you some idea of where to look for the correct settings for your scanner.
When you have this right, in Photoshop the image will look like a negative image, usually dark and flat, and when you look at Image->Mode, it should have 16-Bits/Channel already checked.
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