Epson Scan: What is 'Color Control' doing exactly?

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I don't know if this will help. But when I first got my Epson V600 ten years ago and scanned color film, I found I could get the same color corrections by scanning with No Color Correction and then using Auto Levels in Photoshop Elements on the "flat" image file. Levels have to do with black and white points. However, I cannot seem to duplicate the ease that Elements does it when I try to do it with Lightroom. I don't have regular Photoshop so I can't comment on its editing. Of course, none of this may help with prints, but who knows?

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My underwater Ektachrome slides were drab due to the absorption of color due to being underwater. What surprised me was when I used Color Control with my V600. It brought back the colors greater than I recall them being in the original slide of 30 years ago.

There are some variables even with Auto Color Control that you can change in Epsonscan. Have you checked the manual? Which manual do you have? There are different ones that have more or less instructions than the other. What scanner are you using?

Also, click on Configuration at the bottom that takes you to another page where there are some other adjustments. Maybe you can limit some of these for the scan yet leave enough room for additional adjustments in post.

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My belief hasn't changed in ten years of scanning with the V600 and V850. Scans are static. All changes made by Epsonscan and the other scan programs are made after the scan not before or during. You can actually see this on a pre scan.

First do a prescan. Then go to configuration and turn auto color control on and off. You will see that the display of the prescan results go from flat with no edits to proper color exposure when you switch to auto color control. Since the scanner is not scanning again but using the same scanned results, it obviously supplying those changes to the already scanned image file. That's exactly what happens on the final scan. You can also apply manual changes to the prescan.

The only difference in the final scan is the scan slows down to collect higher resolution and bits, But the edits are done after the scan is completed. So there's really no reason to learn another editing program in the san software. Just use it to scan "flat" and apply all the edits afterwards in you favorite post processing software.

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Originally Posted by Ninny148

Thanks Alan, that definitely matches my experiences with the software.

Edit: In doing some googling, I've come across this page which you might be interested in. I'm not sure it affects me directly (as I'm scanning prints), but the author found that adjusting the histogram for negative scans varied the scan time substantially -- from 1.5 mins to around 5 mins. This suggests that the scanner may be adjusting the exposure time for negatives at a physical level, and not just as an after effect achieved in software. I would be interested to hear if you've had similar experiences. I've tested it with prints and found the scan time didn't change, but have yet to have a go with negatives.

Also, seeing as you and I seem to have a similar approach to these things, can I ask one final question?

When you take your initial scan, do you move the input/output levels in the histogram to 0 and 255? My thinking here is that this captures all colour information the scanner is capable of resolving without any tweaking post-scan. However, Epson Scan seems rather insistent on narrowing the range by default, I think to something like 10 and 245. I figure this is because pure whites and blacks can cause trouble with some printers, e.g. by not depositing any ink in areas with pure whites, which would produce a strange variance in gloss across the photo paper. Perhaps Epson is just trying to idiot-proof the process?

Thanks again for your help, Alan.

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I've never seen a difference in scan time with the Epson V600 or V850 by changing the histogram settings. Using ICE doubles the scan time. Changing the resolution changes it too, I believe. But I always use 2400.

I sometimes set the histogram to the edges of where the image shows. So for example, if the image shows 15 to 200, I'll set it at 10 to 215. People have claimed you get more data that way but I have;t been able to confirm that. It may be the same results as scanning flat 0-255 (in and out) and adjusting the levels (black and white points) in post. I've done it that way too and frankly, can't see the difference. Either way, I do final tweaking in post-processing.

I don;t use the auto setting because for some reason it seem to set it less than the picture's histogram range.

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Originally Posted by Ninny148

I just had another go with auto levels in Photoshop. Unfortunately, it over-exposed the image

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You can set the limit on clipping the edge of the histogram for auto adjustment in Photoshop. Try 250 or thereabouts instead of the default.