scanning TEM (bw) negatives: auto contrast

C
Posted By
cb750
Jan 5, 2006
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646
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1
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Hello,

I am scanning TEM (transmission electron microscopy) negatives using PS

CS and Epson Perfection Photo 4990. In these negatives, there is a small rectangular area on the bottom which has some information like micron bar, etc. This area is in complete contrast with the remaining part of the image. For a long time, I would scan negatives and everytime it would give me different results (image contrast). I just realized that it was doing so because it has some kind of auto contrast, which would change the image depending upon the area I select

with the marquee during scanning. If I select only a part of the film (without the transparent area in the bottom), it would give me results as expected. I also noticed that if there is a feature in the micrograph which has higher contrast, like a dark precipitate, it will further increase the contrast. I just want my scanner software/PS to scan as I shot the film, not to act smart on its own.

Is there a way to disable this auto contrast? I went into configurations and tried a few things but could not fix the problem. It

is important for me to scan the whole film as it is, including the bar in the bottom.

Alpesh

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RF
Robert Feinman
Jan 5, 2006
In article ,
says…
Hello,

I am scanning TEM (transmission electron microscopy) negatives using PS
CS and Epson Perfection Photo 4990. In these negatives, there is a small rectangular area on the bottom which has some information like micron bar, etc. This area is in complete contrast with the remaining part of the image. For a long time, I would scan negatives and everytime it would give me different results (image contrast). I just realized that it was doing so because it has some kind of auto contrast, which would change the image depending upon the area I select
with the marquee during scanning. If I select only a part of the film (without the transparent area in the bottom), it would give me results as expected. I also noticed that if there is a feature in the micrograph which has higher contrast, like a dark precipitate, it will further increase the contrast. I just want my scanner software/PS to scan as I shot the film, not to act smart on its own.

Is there a way to disable this auto contrast? I went into configurations and tried a few things but could not fix the problem. It
is important for me to scan the whole film as it is, including the bar in the bottom.

Alpesh
Are you using the Epson scanning software? If you are you need to go to the most advanced mode and then you will be able to turn off the auto processing.
Another option is to try the shareware scanning software called Vuescan. Go to hamrick.com to download a trial. It allows for many more scanning options than the Epson supplied software. You might also want to read the comp.periphs.scanners news group there has been lots of discussions about this model over the past several months.

Robert D Feinman
Landscapes, Cityscapes and Panoramic Photographs
http://robertdfeinman.com
mail:

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