LaserSoft Imaging

I am using SF AI and HDR (6.4.1r4b) on Windows with a Nikon LS4000 ED. Some weeks ago I bought an IT8 slide (Kodak) for calibration.

On many slides it works fine, colors look much more natural. But as soon as I work on a slide with dark shadows or dark areas I often get posterized colors in those areas. The only way to work around that I found by now is to NOT use color management for these slides and to work on the original scan. (I started to scan in SF AI without color management and to apply it in HDR). Which of cause leads to color problems.

What can I do about it?


And I would like to know how the IT8 slide is supposed to look like after calibration. Without calibration HDR shows too much blue in it (greyscale 11 shows 114,130,135). When I apply color management its redish (130,120,115). At least with the color profile that came with my monitor (Samsung 243T).

If I choose another color profile for 'Intern' like Adobe RGB (1998) the image on the screen is refreshed but doesn't change (it still looks redish) yet the densitometer shows 100,107,115.

Why is the image still redish? Or to put it differently what is the densitometer showing? Is it showing the color as it is supposed to look like (lets say a neutral grey 128,128,128) or does it show the color that is sent to the monitor in order to produce a color that looks neutral grey?

The later case would explain why I get different numbers but the same appearance of the image. And it would also mean that my calibration is skewed to red in the grey scales.

Taking a screenshot opening it in Photohsop gives me 138,128,123 at gray 11 - which actually is redish.

Any light on this will be very much appreciated!

Thanks a lot
Joerg

Dear Joerg

The IT8 calibration matches image data from scannerRGB to internalRGB in such a way that the IT8 slide gets the Lab data that are listed in the reference file corresponding to this IT8 target. If the slide itself has a slight color cast on the gray scale and the reference data describe that correctly, then it is ok when the RGB data there are not all equal.
Changing your internalRGB color space in SilverFast will change the RGB values that you read on the densitometer (and later on when you open your resulting image, e.g. in Photoshop) because the scanner data are now transformed to a different color space.
But as SilverFast does a color matching from internalRGB to monitor color space, too, your monitor will show you the same color appearance (apart from possible clipping) with any internalRGB you choose.

With respect to your problem in the dark parts, please provide me with your email address and I will send you a plugin.

Best regards
Martin

Dear Martin,

Thanks for your reply, it made things much clearer for me.

Maybe you could hint me to what colorspace to use for images that are delivered to people who use programs that do not support color management. When I look at the densitometer values for gray11 between AdobeRGB (100,107,115) and the profile for my monitor (130,120,115) I assume the results will be very different. My idea is to work on the images using my monitor profile and then to use photoshop to transfer the images to some profile that gives a fair probability to produce similar results on programs without color management. Any recommendation?

And thanks for your offer to send a plugin. My email address is:
Joerg.vanHoorn@t-online.de

Best regards
Joerg

Dear Joerg,

I would recommend to work with that RGB color space you want the images to be finally in, otherwise you risk that the conversion at the end will clamp you image. Maybe sRGB is a choice, then.

Best regards
Martin

I have the same problem with posterization afte calibrating for Kodak Ektachrome slides. Fuji calibration works fine.
If that plugin helps, could you send me that plugin as well?

Thanks

Dear Matteo,

please download the current plugin from the www.SilverFast.com website.

Best regards
Martin

Could you be more precise please. What plugin are you referring to? I use the latest AI version 6.4.2.

LSI_Muenier wrote:Dear Matteo,

please download the current plugin from the www.SilverFast.com website.

Best regards
Martin