Hello All,
In the past I have scanned several thousand color negatives to 48 bits TIFF images treating them as positives. I used a Minolta Dimage Scan Elite 5400 machine. The reason I didn't use the Minolta software option to scan them as negatives, thus obtaining positive images is that I didn't trust their conversion algorithm. I used Photoshop to do my own conversion, with varying success.
Is there a way to use CM to do the conversion? I have available in nearly every scan a small area of the orange background, and I suspect that using this information, apply the correct gamma and invert the image, this should be possible. But I lack experience with CM to do the "backgroud subtraction" and the conversion. Is there anyone who could help me?
I attach an example (24 bit jpg) reduced to 20% just to illustrate the kind of images I have available.
A way to directly convert color negative scan to positive image?
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- Joined: Tue Nov 07, 2006 11:41 am
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- Posts: 460
- Joined: Tue Nov 07, 2006 11:41 am
Alex, have you done a CM 101 class with Greg? I see there's one coming up soon. Greg will teach you how to do it. I did this in about 4 steps in CM,firstly by moving the diagonal line in the lightness canal of Lab through 90°, so that the lower end is right and upper end left. After that I did a color correction by the numbers firstly through RGB and lastly a color boost in Lab.
Everyone,
Here is a link to the Video describing how to make this conversion in Curvemeister.
http://youtu.be/lrIDpLVpqTk
Greg
Here is a link to the Video describing how to make this conversion in Curvemeister.
http://youtu.be/lrIDpLVpqTk
Greg
Ganna: Yes I did the class several years ago. Also I studied the book Photoshop LAB Color by Dan Margulis, but I don't remember seeing anything in it that would be helpful.
I did try to reverse the L-channel line, but the result is disapointing: the image is totally off color. In a different image a bright red cushion shows as a dark green one. I don't see how this could lead to a more natural image. Shouldn't the a and b channels also be inverted?
I did try to reverse the L-channel line, but the result is disapointing: the image is totally off color. In a different image a bright red cushion shows as a dark green one. I don't see how this could lead to a more natural image. Shouldn't the a and b channels also be inverted?
Greg:
This is really very enlightening, your video. I'll come back when I have tried it a few times on different images. Do you think there could be a library file (.acv) made that does the job for a set of color negatives made under the same conditions?
I am ashamed to say that I have used CM very little these past few years - I have to find out all about it again!
Thanks very much, Greg!
This is really very enlightening, your video. I'll come back when I have tried it a few times on different images. Do you think there could be a library file (.acv) made that does the job for a set of color negatives made under the same conditions?
I am ashamed to say that I have used CM very little these past few years - I have to find out all about it again!
Thanks very much, Greg!
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